Helsinki microsurgery basics and tricks

Lehecka|Laakso|HernesniemiHelsinkiMicroneurosurgery|BasicsandTricks
Depar
tm
ent of Neuros
urgery
Est. 1932
Univ
ersity of Helsinki
Fi
nland
Depar
tm
ent of Neuros
urgery
Est. 1932
Univ
ersity of Helsinki
Fi
nland
Helsinki Microneurosurgery
Basics and Tricks
Martin Lehecka, Aki Laakso
and Juha Hernesniemi
Foreword by Robert F. Spetzler
Depar
tm
ent of Neuros
urgery
Est. 1932
Univ
ersity of Helsinki
Fi
nland
Depar
tm
ent of Neuros
urgery
Est. 1932
Univ
ersity of Helsinki
Fi
nland
Department of Neurosurgery at Helsinki University, Finland, led by its chairman Juha
Hernesniemi, has become one of the most frequently visited neurosurgical units in the
world. Every year hundreds of neurosurgeons come to Helsinki to observe and learn
microneurosuergery from Professor Juha Hernesniemi and his team.
In this book we want to share the Helsinki experience on conceptual thinking behind
what we consider modern microneurosurgery. We want to present an up-to-date
manual of basic microneurosurgical principles and techniques in a cook book fashion.
It is our experience that usually the small details determine whether a particular
surgery is going to be successful or not. To operate in a simple, clean, and fast way
while preserving normal anatomy has become our principle in Helsinki.

Basics and Tricks
By Martin Lehecka, Aki Laakso and Juha Hernesniemi
Depar
tm
ent of Neuros
urgery
Est. 1932
Univ
ersity of Helsinki
Fi
nland
Depar
tm
ent Neuros
urgery
Est. 1932
HelsinkiU
niversity Central Hospita
l
Finland
Collaborators:
Özgür Çelik
Reza Dashti
Mansoor Foroughi
Keisuke Ishii
Ayse Karatas
Johan Marjamaa
Ondrej Navratil
Mika Niemelä
Tomi Niemi
Jouke S. van Popta
Tarja Randell
Rossana Romani
Ritva Salmenperä
Rod Samuelson
Felix Scholtes
Päivi Tanskanen
Photographs:
Jan Bodnár
Mansoor Foroughi
Antti Huotarinen
Aki Laakso
Video editing:
Jouke S. van Popta
Drawings:
Hu Shen
Helsinki, Finland 2011

Basics and Tricks
By Martin Lehecka, Aki Laakso
and Juha Hernesniemi
1. Edition 2011
© M. Lehecka, A. Laakso, J. Hernesniemi 2011
Layout: Aesculap AG | D-NE11002
Print: Druckerei Hohl GmbH & Co. KG / Germany
ISBN 978-952-92-9084-0 (hardback)
ISBN 978-952-92-9085-7 (PDF)
Author contact information:
Martin Lehecka, MD, PhD
email: martin.lehecka@hus.fi
tel: +358-50-427 2500
Aki Laakso, MD, PhD
email: aki.laakso@hus.fi
tel: +358-50-427 2895
Juha Hernesniemi, MD, PhD
Professor and Chairman
email: juha.hernesniemi@hus.fi
tel: +358-50-427 0220
Department of Neurosurgery
Helsinki University Central Hospital
Topeliuksenkatu 5
00260 Helsinki, Finland
Disclosure statement:
Helsinki Neurosurgery organizes annually
”The Helsinki Live Demonstration Course“ in
Operative Microneurosurgery in collaboration
with Aesculap Academy. The authors have no
personal financial interests to disclose.

Every man owes it as a debt to his profession to put on record whatever
he has done that might be of use for others.
Francis Bacon (1561-1626)
Simple, clean, while preserving normal anatomy. Clean is fast and
effective. Surgery is art - you should be one of the artists.
Juha Hernesniemi

Acknowledgements
The authors would like to thank Aesculap, a B. Braun company, for kindly supporting printing of
this book, with special thanks to Ingo vom Berg, Bianca Bauhammer and Outi Voipio-Airaksinen.
In addition, the authors want to express their gratitude to the administration of Helsinki Univer-
sity Central Hospital for their support over the past years.

FOREWORD
by Robert F. Spetzler
Fortunate are the neurosurgeons who have the
opportunity to visit the Department of Neu-
rosurgery at the Helsinki University Central
Hospital and receive this delightful volume as
a souvenir for it is likely to be one of the most
charming books they will ever read about neu-
rosurgery. As the title indicates, Drs. Lehecka,
Laakso, and Hernesniemi have written about
neurosurgery as performed in Helsinki. How-
ever, they have done so much more than that —
they have captured the deeply rooted spirit of
camaraderie and commitment that has helped
build Helsinki into an international center of
neurosurgical excellence under the leadership
of Juha Hernesniemi and his colleagues. Nor is
the term international an overstatement when
applied to a department in this far northern
clime. Indeed, their list of distinguished visi-
tors reads like an international Who's Who of
Neurosurgery.
One can almost hear the Finnish cadences as
the authors share amusing vignettes (although
some were likely to have been alarming at the
time of their occurrence) from the history of
Finnish neurosurgery. More importantly, read-
ers cannot miss the natural warmth, honesty,
and integrity of these authors in their discus-
sions of Helsinki philosophies, routines, and
practices. These qualities are underscored by
several essays contributed by a variety of train-
ees who each provide entertaining accounts of
their time spent in Helsinki. That their lives
were altered profoundly by the experience is
unmistakable. Juha's taciturn but gentle hu-
mor, his intense devotion to perfecting his sur-
gical expertise to better serve his patients, and
his dedication to mentoring inspire a lifelong
admiration and loyalty among his trainees and
colleagues. Of course, readers will find con-
siderable practical advice on the fundamental
practice of neurosurgery in chapters devoted to
principles of microneurosurgery, approaches,
specific strategies for treating various patholo-
gies, and neuroanesthesiology.
Especially important points are summarized
under the heading, T&T, that is, Tricks and Tips
from Juha-Helsinki pearls. Seasoned surgeons
will benefit from analyzing how their own sur-
gical style differs from that of Juha's.
Every detail of the Helsinki approach to neu-
rosurgery is covered, including how Juha ex-
pects his operating room to run to lists of his
personal habits and instruments intended to
ensure that his coworkers understand how his
operations will proceed. The advantages to pa-
tients of such a finely tuned team, sensitive to
the surgeon's needs and expectation, should
never be underestimated. This refined team-
work ensures that neurosurgical procedures are
completed in as efficient and safe manner as is
possible, thereby optimizing the chances of a
good outcome for the patient. Juha's ability to
promote such precision teamwork is but one of
his amazing talents.
Juha is truly a master neurosurgeon and to be
able to experience his passion for, insight into,
and dedication to neurosurgery is a rare privi-
lege. His philosophy of simple, clean, and fast
surgery that preserves normal anatomy is one
that we all should emulate. By sharing both his
expertise and his humanity in this volume, Juha
lights a Socratic path worth following, a path
based on respect and tolerance for different
approaches that encourages growth while still
respecting proven expertise. Those fortunate
enough to visit Helsinki experience these rare
qualities firsthand; those unable to make that
pilgrimage can still count themselves lucky to
read this volume.

Robert F. Spetzler, MD
Phoenix, Arizona; November 2010

Table of Contents
1. INTRODUCTION 13
2. DEPARTMENT OF NEUROSURGERY, HELSINKI
UNIVERSITY CENTRAL HOSPITAL 17
2.1. HISTORY OF NEUROSURGERY IN HELSINKI
AND FINLAND 17
2.1.1. Aarno Snellman, founder of Finnish
neurosurgery 17
2.1.2. Angiography in Finland 18
2.1.3. World War II and late 1940’s 19
2.1.4. Microneurosurgery and endovascular
surgery 20
2.1.5. Changes towards the present time 21
2.2. PRESENT DEPARTMENT SETUP 24
2.3. STAFF MEMBERS 24
2.3.1. Neurosurgeons 25
2.3.2. Neurosurgical residents 30
2.3.3. Neuroanesthesiologists 30
2.3.4. Neuroradiologists 31
2.3.5. Bed wards 32
2.3.6. Intensive care unit (ICU) 34
2.3.7. Operating rooms 36
2.3.8. Administrative personnel 37
2.4. OPERATING ROOM COMPLEX 40
2.4.1. Operating room complex design 40
2.4.2. Operating room ambience 41
3. ANESTHESIA 45
3.1. GENERAL PHYSIOLOGICAL PRINCIPLES
AND THEIR IMPACT ON ANESTHESIA 46
3.1.1. Intracranial pressure 46
3.1.2. Autoregulation of cerebral blood flow 47
3.1.3. CO2
reactivity 48
3.1.4. Cerebral metabolic coupling 49
3.2. MONITORING OF ANESTHESIA 50
3.3. PREOPERATIVE ASSESSMENT AND
INDUCTION OF ANESTHESIA 51
3.4. MAINTENANCE OF ANESTHESIA 53
3.5. TERMINATION OF ANESTHESIA 55
3.6. FLUID MANAGEMENT AND BLOOD
TRANSFUSIONS 56
3.7. ANESTHESIOLOGICAL CONSIDERATIONS
FOR PATIENT POSITIONING 57
3.7.1. Supine position 57
3.7.2. Prone, lateral park bench and
kneeling positions 58
3.7.3. Sitting position 62
3.8. POSTOPERATIVE CARE IN THE ICU 63
3.9. SPECIAL SITUATIONS 65
3.9.1. Temporary clipping in aneurysm
surgery 65
3.9.2. Adenosine and short cardiac arrest 66
3.9.3. Intraoperative neurophysiologic
monitoring 66
3.9.4. Antithrombotic drugs and
thromboembolism 67
4. PRINCIPLES OF HELSINKI
MICRONEUROSURGERY 69
4.1. GENERAL PHILOSOPHY 69
4.2. PRINCIPLES OF MICRONEUROSURGERY 70
4.3. OPERATING ROOM SETUP 71
4.3.1. Technical setup 71
4.3.2. Displays 72
4.4. POSITIONING AND HEAD FIXATION 73
4.4.1. Operating table 73
4.4.2. Patient positioning 73
4.4.3. Neurosurgeon’s position and
movement 74
4.4.4. Head fixation 76
4.5. NECESSARY OR USEFUL TOOLS 77
4.5.1. Operating microscope 77
4.5.2. Armrest 79
4.5.3. Bipolar and diathermia 79
4.5.4. High speed drill 80
4.5.5. Ultrasonic aspirator 82
4.5.6. Fibrin glue 83
4.5.7. Indocyanine green angiography 84
4.5.8. Microsurgical doppler and flowmeter 85
4.5.9. Neuronavigator 86
4.5.10. Intraoperative DSA 87
4.6. MICROINSTRUMENTS 88
4.7. SOME HABITS IN PREPARATION AND DRAPING 90
4.8. GENERAL PRINCIPLES OF CRANIOTOMY 92
4.9. BASIC MICROSURGICAL PRINCIPLES OF
HELSINKI STYLE MICRONEUROSURGERY 94
4.9.1. Simple, clean, fast and preserving
normal anatomy 94
4.9.2. Movements under the microscope 95
4.9.3. Moving the microscope 98
4.9.4. Left hand – suction 99
4.9.5. Right hand 100
4.9.6. Bipolar forceps 101
4.9.7. Microscissors 102
4.9.8. Cottonoids 102
4.9.9. Sharp and blunt dissection 103
4.9.10. Irrigation and water dissection 103
4.9.11. Minimal retraction 104

4.10. CLOSING 104
4.11. KEY FACTORS IN HELSINKI STYLE
MICRONEUROSURGERY 105
4.12. LIST OF PROF. HERNESNIEMI’S GENERAL
HABITS AND INSTRUMENTS 106
5. COMMON APPROACHES 111
5.1. LATERAL SUPRAORBITAL APPROACH 111
5.1.1. Indications 111
5.1.2. Positioning 112
5.1.3. Incision and craniotomy 113
5.2. PTERIONAL APPROACH 118
5.3. INTERHEMISPHERIC APPROACH 124
5.4. SUBTEMPORAL APPROACH 132
5.4.3. Skin incision and craniotomy 135
5.5. RETROSIGMOID APPROACH 144
5.6. LATERAL APPROACH TO FORAMEN MAGNUM 156
5.7. PRESIGMOID APPROACH 160
5.8. SITTING POSITION – SUPRACEREBELLAR
INFRATENTORIAL APPROACH 170
5.9. SITTING POSITION – APPROACH TO THE
FOURTH VENTRICLE AND FORAMEN
MAGNUM REGION 183
6. SPECIFIC TECHNIQUES AND STRATEGIES FOR
DIFFERENT PATHOLOGIES 195
6.1. ANEURYSMS 195
6.1.1. Approaches for different aneurysms 195
6.1.2. General strategy for ruptured
aneurysms 196
6.1.3. General strategy for unruptured
aneurysms 197
6.1.4. Release of CSF and removal of ICH 197
6.1.5. Dissection towards the aneurysm 199
6.1.6. Opening of the Sylvian fissure 200
6.1.7. Temporary clipping 201
6.1.8. Final clipping and clip selection 203
6.1.9. Intraoperative rupture 203
6.1.10. Adenosine 206
6.2. ARTERIOVENOUS MALFORMATIONS 207
6.2.1. General strategy in AVM surgery 207
6.2.2. Preoperative embolization 207
6.2.3. Approaches 208
6.2.4. Dural opening and initial dissection 208
6.2.5. Further dissection and use of
temporary clips 210
6.2.6. Coagulation and dissection of small
feeders 211
6.2.7. Final stage of AVM removal 212
6.2.8. Final hemostasis 212
6.2.9. Postoperative care and imaging 212
6.3. CAVERNOMAS 214
6.3.1. General strategy in cavernoma
surgery 214
6.3.2. Intraoperative localization 214
6.3.4. Dissection and removal 216
6.3.5. Postoperative imaging 217
6.4. MENINGIOMAS 218
6.4.1. General strategy with convexity
meningiomas 218
6.4.2. General strategy with parasagittal
meningiomas 219
6.4.3. General strategy with falx and
tentorium meningiomas 221
6.4.4. General strategy with skull base
meningiomas 222
6.4.5. Tumor consistency 224
6.4.7. Devascularization 225
6.4.8. Tumor removal 225
6.4.9. Dural repair 226
6.5. GLIOMAS 227
6.5.1. General strategy with low-grade
gliomas 227
6.5.2. General strategy with high-grade
gliomas 228

6.5.4. Intracranial orientation and
delineation of the tumor 229
6.6. COLLOID CYSTS OF THE THIRD VENTRICLE 231
6.6.1. General strategy with colloid cyst
surgery 231
6.6.2. Positioning and craniotomy 231
6.6.3. Interhemispheric approach and
callosal incision 232
6.6.4. Colloid cyst removal 233
6.7. PINEAL REGION LESIONS 234
6.7.1. General strategy with pineal region
surgery 234
6.7.2. Approach and craniotomy 235
6.7.3. Intradural approach 235
6.7.4. Lesion removal 235
6.8. TUMORS OF THE FOURTH VENTRICLE 236
6.8.1. General strategy with fourth
ventricle tumors 236
6.8.2. Positioning and craniotomy 237
6.8.3. Intradural dissection towards the
fourth ventricle 237
6.9. SPINAL INTRADURAL TUMORS 240
6.9.1. General strategy with intradural
spinal lesions 240
6.9.3. Approach 242
6.9.4. Intradural dissection 243
6.9.5. Closure 243
7. NEUROSURGICAL TRAINING, EDUCATION
AND RESEARCH IN HELSINKI 245
7.1. NEUROSURGICAL RESIDENCY IN HELSINKI 245
7.1.1. Residency program 245
7.1.2. How to become a neurosurgeon
in Helsinki – the resident years –
Aki Laakso 246
7.2. ACADEMIC AND RESEARCH TRAINING 250
7.2.1. PhD program 250
7.2.2. Making of a PhD thesis in Helsinki,
my experience – Johan Marjamaa 250
7.3. MICRONEUROSURGICAL FELLOWSHIP
WITH PROFESSOR HERNESNIEMI 253
7.4. MEDICAL STUDENTS 254
7.5. INTERNATIONAL VISITORS 254
7.6. INTERNATIONAL LIVE SURGERY COURSES 256
7.6.1. Helsinki Live Course 256
7.6.2. LINNC-ACINR course (Organized
by J. Moret and C. Islak) 258
7.7. PUBLICATION ACTIVITY 260
7.8. RESEARCH GROUPS AT HELSINKI
NEUROSURGERY 261
7.8.1. Biomedicum group for research
on cerebral aneurysm wall 261
7.8.2. Translational functional
neurosurgery group 262
7.8.3. Helsinki Cerebral Aneurysm
Research (HeCARe) group 262
8. VISITING HELSINKI NEUROSURGERY 265
8.1. TWO YEAR FELLOWSHIP –
JOUKE S. VAN POPTA (ZARAGOZA, SPAIN) 265
8.1.1. Why to do a fellowship? 265
8.1.2. In search of a fellowship 266
8.1.3. Checking it out 266
8.1.4. Arrival in Helsinki 266
8.1.5. The very first day 266
8.1.6. A day in the life (of a fellow) 267
8.1.7. Assisting in surgery 267
8.1.8. Nurses 268
8.1.9. Anesthesiologists 268
8.1.10. Music in the OR 269
8.1.11. Rounds 269
8.1.12. Visitors 271
8.1.13. Pins and their stories 271
8.1.14. LINNC and Live Course 271
8.1.15. Weather and the four seasons 272
8.1.16. Apartments 273
8.1.17. Helsinki 273
8.1.18. Finnish food 273
8.1.19. Languages 273
8.1.20. Famous words 274
8.1.21. Practice, practice, practice 274
8.1.22. Video editing 274
8.1.23. The surgery of Juha Hernesniemi 274
8.1.24. The choice of a fellowship 275
8.2. ADAPTING TO FINNISH CULTURE AND
SOCIETY – ROSSANA ROMANI (ROME, ITALY) 276
8.2.1. The difference between “to talk
the talk” and “to walk the walk” 276
8.2.2. Difficult to learn but good for life:
The Finnish language 274
8.2.3. When in Finland do as the Finns 280
8.2.4. Never good weather 281
8.2.5. Finnish attitude: “Sisu” 283
8.2.6. He and she = hän 283
8.2.7. Conclusions 283
8.3. IMPRESSIONS OF HELSINKI: ACCOUNT OF
A VISIT – FELIX SCHOLTES (LIÈGE, BELGIUM) 284
8.4. TWO YEARS OF FELLOWSHIP AT THE
DEPARTMENT OF NEUROSURGERY IN HEL-
SINKI – REZA DASHTI (ISTANBUL, TURKEY) 290
TABLE OF CONTENTS

8.5. MY MEMORIAL OF “GO GO SURGERY”
IN HELSINKI - KEISUKE ISHII (OITA, JAPAN) 294
8.5.1. The first impression of Finns 294
8.5.2. The Helsinki University Central
Hospital 294
8.5.3. Professor Hernesniemi and his
surgical techniques 294
8.5.4. My current days in Japan 295
8.5.5. To conclude 295
8.6. AFTER A ONE-YEAR FELLOWSHIP – ONDREJ
NAVRATIL (BRNO, CZECH REPUBLIC) 296
8.7. ONE-YEAR FELLOWSHIP AT THE DEPART-
MENT OF NEUROSURGERY IN HELSINKI –
ÖZGÜR ÇELIK (ANKARA, TURKEY) 300
8.8. SIX MONTH FELLOWSHIP – MANSOOR
FOROUGHI (CARDIFF, UNITED KINGDOM) 302
8.8.1 How it began 302
8.8.2. The place and the people 303
8.8.3. The Rainbow team and its Chairman 304
8.9. TWO MONTH FELLOWSHIP – ROD
SAMUELSON (RICHMOND, VIRGINIA) 308
8.10. MEMORIES OF HELSINKI – AYSE KARATAS
(ANKARA, TURKEY) 312
9. SOME CAREER ADVICE TO YOUNG
NEUROSURGEONS 315
9.1. READ AND LEARN ANATOMY 316
9.2. TRAIN YOUR SKILLS 316
9.3. SELECT YOUR OWN HEROES 316
9.4. KEEP FIT 317
9.5. BE A MEDICAL DOCTOR, TAKE
RESPONSIBILITY! 318
9.6. LEARN YOUR BEST WAY OF DOING YOUR
SURGERY 318
9.7. OPEN DOOR MICROSURGERY 319
9.8. RESEARCH AND KEEP RECORDS 319
9.9. FOLLOW UP YOUR PATIENTS 320
9.10. WRITE AND PUBLISH 320
9.11. KNOW YOUR PEOPLE 321
9.12. ATMOSPHERE 321
10. LIFE IN NEUROSURGERY: HOW I BECAME
ME – JUHA HERNESNIEMI 333
11. FUTURE OF NEUROSURGERY 333
APPENDIX 1. PUBLISHED ARTICLES ON MICRO-
NEUROSURGICAL AND NEUROANESTHESIOLO-
GICAL TECHNIQUES FROM HELSINKI 337
APPENDIX 2. LIST OF ACCOMPANYING VIDEOS 342

13
1. INTRODUCTION
Such a complex labyrinthine approach through
the cranium and brain, however, requires accu-
rate preoperative planning and the preparation
of a prospective surgical concept (including
anticipated variations), which is based on a
firm knowledge of anatomy, microtechniques,
and surgical experience. These elements con-
stitute the art of microneurosurgery.
M.G. Yaşargil 1996 (Microneurosurgery vol IVB)
Much of the merit of an approach is a matter
of surgical experience. We always attempted
to make these operations simpler, faster and to
preserve normal anatomy by avoiding resection
of cranial base, brain or sacrifice of veins.
C.G. Drake, S.J. Peerless, and J. Hernesniemi 1996
Sometimes I look into the small craniotomy ap-
proach without the help of a microscope, and
think of the neurosurgical pioneers, Olivecrona
from Stockholm and his pupils here in Helsinki,
Snellman and af Björkesten. I was never trained
by them, they came before my time, but I re-
ceived my neurosurgical training already at the
hands of their pupils. I also think of Professor
C.G. Drake, what might have been his feelings
when approaching the basilar tip for the first
time. Personally, I am terrified of this tiny deep
gap, the lack of light, the fear of all the things
that might lie in there, of all the things that
cannot be seen with the bare eye. But at the
same time, I also feel happiness because of all
the different tools and techniques we nowa-
days have. Tools that have changed our whole
perception of neurosurgery from something
scary into something extremely delicate. Micro-
neurosurgical techniques, mainly introduced by
Professor Yaşargil, have revolutionized our pos-
sibilities to operate in a small and often very
deep gap in total control of the situation and
without the fear of the unknown. I still feel
fear before every surgery, but it is no longer
the fear of the unknown; rather, it is a fear of
whether I will be successful in executing the
pre-planned strategy with all its tiny details
and possible surprises along the way. But all
this anxiety subsides immediately once the fas-
cinating and beautiful microanatomical world
opens up under the magnification of the oper-
ating microscope. This loss of fear means bet-
ter surgery, as hesitance and tremor associated
with fear are replaced with a strong feeling of
success, determination and steady hands. The
fear is also in an equal way lost to a minimum
when looking around and seeing the experi-
enced and supporting Helsinki team around,
and exchanging few words with them before
and during surgery. As Bertol Brecht said, Finn-
ish people are queit in two languages.
Big resistance against microsurgery was still
seen at the end of 70's when I was trained in
Helsinki. The reluctance towards new think-
ing, although often irrational, is very common
both in surgical as well as other human areas.
Arguments such as "the really good neuro-
surgeons can operate on aneurysms without
a microscope..." were common at that time.
Fortunately, this kind of thinking has already
disappeared among Finnish neurosurgeons, but
the same thoughts still prevail in many parts
of the world. In many countries unskilled neu-
rosurgeons with old-fashioned thinking still
continue cruel surgery, and bring misery to the
patients, families and the surrounding society.
The motto "do not harm" is forgotten. It is clear
that an epidural hematoma can be removed
without a microscope, but already removing a
big convexity meningioma using microneuro-
surgical techniques helps in getting far better
results.
Microneurosurgery does not solely refer to the
use of the operating microscope; rather, it is a
conceptual way of planning and executing all
stages of the operation utilizing the delicate
techniques of handling the different tissues. A
true microsurgical operation starts already out-
Introduction | 1

14
side of the operating room with careful preop-
erative planning and continues throughout all
the steps of the procedure. Mental preparation,
repetition of earlier experience, good knowl-
edge of microanatomy, high quality neuroan-
esthesia, seamless cooperation between the
neurosurgeon and the scrub nurse, appropriate
strategy and its execution are all essential ele-
ments of modern microneurosurgery.
In this book we want to share our experience
from Helsinki on some of the conceptual think-
ing behind what we consider modern microne-
urosurgery. We want to present an up-to-date
manual of basic microneurosurgical principles
and techniques in a cookbook fashion. It is my
experience, that usually the small details de-
termine whether the procedure is going to be
successful or not. To operate in a simple, clean,
and fast way while preserving normal anatomy;
that has become my principle during and after
more than 12,000 microsurgical operations.
Juha Hernesniemi
Helsinki, August 15th 2010
1 | Introduction

17
History of Neurosurgery in Helsinki and Finland | 2
2.1. HISTORY OF NEUROSURGERY IN HELSINKI
AND FINLAND
2.1.1. Aarno Snellman, founder of
Finnish neurosurgery
The first neurosurgical operations in Finland
were performed in the beginning of the 20th
century by surgeons such as Schultén, Krogius,
Faltin, Palmén, Kalima and Seiro, but it is Aarno
Snellman who is considered the founder of
neurosurgery in Finland. The Finnish Red Cross
Hospital, which was the only center for Finnish
neurosurgery until 1967, was founded in 1932
by Marshall Mannerheim and his sister Sophie
Mannerheim as a trauma hospital. It is in this
same hospital where the Helsinki Neurosur-
gery is still nowadays located. Already during
the first years the number of patients with dif-
ferent head injuries was so significant that an
evident need for a trained neurosurgeon and
special nursing staff arose. In 1935, professor
of surgery Simo A. Brofeldt sent his younger
colleague, 42-year old Aarno Snellman, to visit
professor Olivecrona in Stockholm. Snellman
spent there half a year, closely observing Ol-
ivecrona's work. Upon his return, he performed
the first neurosurgical operation on 18th Sep-
tember 1935. This is generally considered as
the true beginning of neurosurgery in Finland.
Figure 2-1. The Finnish Red Cross Hospital AAAAAAAAAA
(later Töölö Hospital) in 1932.
2. DEPARTMENT OF NEUROSURGERY,
HELSINKI UNIVERSITY CENTRAL HOSPITAL

18
2.1.2. Angiography in Finland
The initially relatively poor surgical results
were mainly due to insufficient preoperative
diagnostics. Realizing the importance of pr-
eoperative imaging, Snellman convinced his
colleague from radiology, Yrjö Lassila, to visit
professor Erik Lysholm in Stockholm. The first
cerebral angiographies were performed after
Lassila's return to Helsinki in 1936. At that time
the angiography was often performed only on
one side as it required surgical exposure of the
carotid artery at the neck and four to six staff
members to perform the procedure that took
a relatively long time: one to hold the needle,
one to inject the contrast agent, one to use the
X-ray tube, one to change the films, one to hold
the patient's head, and one who was responsi-
ble for the lighting. The procedure was quite
risky for the patients; there was one death in
the first 44 cases, i.e. 2% mortality. There were
also some less expected complications such as
one situation, when the surgeon injecting the
contrast agent got an electric shock from the
X-ray tube and fell unconscious to the floor!
While falling he accidentally pulled on the loop
of silk thread, passed under the patient's ca-
rotid artery, causing total transsection of this
artery. Fortunately, the assistant was able to
save the situation and as Snellman stated in his
report, "no one was left with any permanent
consequences from this dramatic situation".
Before 1948 the number of cerebral angiogra-
phies was only 15-20 per year, but with the
introduction of the percutaneous technique at
the end of 1948, the number of angiographies
started gradually to rise, with more than 170
cerebral angiographies performed in 1949.
2 | History of Neurosurgery in Helsinki and Finland
Figure 2-2. (b) Professor Sune Gunnar af Björkesten
(painting by Pentti Melanen in 1972).
Figure 2-2. (a) Professor Aarno Snellman
(painting by Tuomas von Boehm in 1953).

19
2.1.3. World War II and late 1940's
The World War II had a significant effect on the
development of neurosurgery in Finland. On
one hand the war effort diminished the possi-
bilities to treat civilian population, on the other
hand the high number of head injuries boosted
the development of the neurosurgical treat-
ment of head trauma. During this period sev-
eral neurosurgeons from other Scandinavian
countries worked as volunteers in Finland help-
ing with the high casualty load. Among others
there were Lars Leksell, Nils Lundberg and Olof
Sjöqvist from Sweden, and Eduard Busch from
Denmark. After the war, it became evident that
neurosurgery was needed as a separate special-
ty. Aarno Snellman was appointed as a profes-
sor of neurosurgery at the Helsinki University
in 1947 and the same year medical students
had their first, planned course in neurosurgery.
The next year, Teuvo Mäkelä, who worked in
neurosurgery since 1940 and took care of the
head injury patients, was appointed as the first
assistant professor in neurosurgery. An impor-
tant administrative change took place in 1946
when the Finnish government decided that the
state would pay for the expenses for the neu-
rosurgical treatment. With this decision neuro-
surgical treatment became, at least in theory,
available for the whole Finnish population. The
limiting factors were hospital resources (there
was initially only one ward available) and the
relatively long distances in Finland. This is
one of the reasons why especially in the early
years, e.g. aneurysm patients came for opera-
tive treatment several months after the initial
rupture, and only those in good condition were
selected. Neurosurgery remained centralized in
Helsinki until 1967, when the department of
neurosurgery in Turku was founded, later fol-
lowed by neurosurgical departments in Kuopio
(1977), Oulu (1977) and Tampere (1983).
Figure 2-3. Neurosurgical units in Finland and the years
they were established.

20
2.1.4. Microneurosurgery and
endovascular surgery
The first one to use the operating microscope
in Finland was Tapio Törmä in Turku in the be-
ginning of 1970's. The first operating micro-
scope came to the neurosurgical department
in Helsinki in 1974. The economic department
of that time managed to postpone purchase of
this microscope by one year as they considered
it a very expensive and unnecessary piece of
equipment. Initially, the microscope was used
by neurosurgeons operating on aneurysms,
small meningiomas, and acoustic schwanno-
mas. Laboratory training in microsurgical tech-
niques was not considered necessary and sur-
geons usually started to use them immediately
in the operating room (OR). A Turkish born neu-
rosurgeon Davut Tovi from Umeå held a labora-
tory course in Helsinki in January 1975, dur-
ing which he also demonstrated the use of the
microscope in the OR while the intraoperative
scene could be observed from a TV monitor. In-
terestingly, during the first years of microneu-
rosurgery on aneurysms, intraoperative rupture
made the neurosurgeon often to abandon the
microscope and move back to macrosurgery
so that he could "see better" the rupture site.
But the younger generation already started
with microsurgical laboratory training, among
them Juha Hernesniemi, who operated his first
aneurysm in 1976. He has operated all of his
nearly 4000 aneurysms under the microscope.
In 1982 Hernesniemi visited Yaşargil in Zürich,
and after this visit started, as the first in Fin-
land in 1983, to use a counterbalanced micro-
scope with a mouthswitch. Surgery on unrup-
tured aneurysms in patients with previous SAH
started in 1979, and the first paper on surgery
of aneurysms in patients with only incidental,
unruptured aneurysms was published in 1987.
Endovascular treatment of intracranial aneu-
rysms started in Finland in 1991.

21
2.1.5. Changes towards the present time
During the last decades of the 20th century,
advances in the society, technology, neuroim-
aging, and medicine in general also meant an
inevitable gradual progression in neurosurgery,
which had its impact on Helsinki Neurosur-
gery as well. The annual number of opera-
tions increased from 600 in the 70's to about
1000 in the 80's and 1500 in the early 90's.
In the intensive care unit (ICU), although the
clinical neurological condition and the level
of consciousness of the patients were closely
monitored, no invasive monitoring was used
in the early 1980's. Transferring a critically ill
patient to a routine CT scan might have had
catastrophic consequences. However, little by
little, significant advances in neuroanesthesi-
ology began to lead to safer and less tumultu-
ous neurosurgical operations. Development in
this field also had its impact on neurointensive
care, and invasive monitoring of vital functions
– both at the ICU and during transfer of criti-
cally ill or anesthetized patients - as well as
e.g. intracranial pressure monitoring became
routine. Treatment attitude in the ICU changed
from 'maintaining' the patients while wait-
ing for the illness and the physiological repair
mechanisms to take their natural course, to an
active one with strong emphasis on secondary
injury prevention. Much of this development in
Helsinki was due to the work of neuroanesthe-
siologists Tarja Randell, Juha Kyttä and Päivi
Tanskanen, as well as Juha Öhman, the head
of neurosurgical ICU (now the Professor and
Chairman of the Department of Neurosurgery
in Tampere University Hospital).
Still, many aspects of life and daily work at
the Department in 1990's looked very differ-
ent from the present state of affairs. The staff
included only six senior neurosurgeons, three
residents and 65 nurses. Three to four patients
a day were operated in three OR's. Operations
were long; in a routine craniotomy, in addition
to intracranial dissection and treatment of the
pathology itself, just the approach usually took
an hour, and the closure of the wound from one
to two hours. With no technical staff to help,
scrub nurses had to clean and maintain the
instruments themselves at the end of the day,
meaning that no elective operation could start
in the afternoon. All surgeons operated sitting;
unbalanced microscopes had no mouthpieces.
Convexity meningiomas and glioblastomas
were even operated on without a microscope.
The attitude towards elderly and severely ill
patients was very conservative compared with
present day standards – for example, high-
grade SAH patients were not admitted for
neurosurgical treatment unless they started to
show signs of recovery. International contacts
and visitors from abroad were rare. The staff
did participate in international meetings, but
longer visits abroad and clinical fellowships
took only seldom place. Scientific work was en-
couraged and many classical pearls of scientific
literature were produced, such as Prof. Henry
Troupp's studies of natural history of AVMs,
Juha Jääskeläinen's (now Professor of Neuro-
surgery in Kuopio University Hospital) studies
of outcome and recurrence rate of meningi-
omas, and Seppo Juvela's studies on the risk
factors of SAH and hemorrhage risk of unrup-
tured aneurysms. However, it was very difficult
especially for younger colleagues to get proper
financial support for their research at the time.
Doing research was a lonely job – research
groups, as we know them now, did not really
exist at the Department, and the accumulation
of papers and scientific merit was slow.
Probably no one anticipated the pace and ex-
tent of changes that were about to take place
when the new chairman was elected in 1997.
Juha Hernesniemi, a pupil of the Department
from the 70's, having spent almost two decades
elsewhere - mainly in Kuopio University Hospi-

22
tal - returned with intense will and dedication
to shape the Department according to his vi-
sion and dream. In only three years, the annual
number of operations increased from 1600 to
3200, the budget doubled from 10 to 20 mil-
lion euros. It is a common fact in any trade,
that the election of a new leader or a manager
is followed by a "honeymoon" period, during
which the new chief fiercely tries to implement
changes according to his or her will, and to
some extent the administration of the organi-
zation is supposed to support the aims of this
newly elected person – he or she was given the
leadership position by the same administration,
after all. In this particular case, however, people
in the administration got cold feet because of
the volume and the speed of the development.
Since the Department had the same population
to treat as before, where did this increase in
patient numbers come from? Were the treat-
ment indications appropriate? Could the treat-
ment results be appropriate? Soon, an internal
audit was initialized, questioning the actions
of the new chairman. The scrutiny continued
for over a year. The treatment indications and
results were compared to those of other neu-
rosurgical units in Finland and elsewhere in
Europe, and it became evident that the treat-
ment and care given in the Department were
of high quality. The new chairman and his ac-
tive treatment policy also received invaluable
support in form of Professor Markku Kaste, the
highly distinguished chairman of Department
of Neurology. After the rough ride through the
early years, the hospital administration and the
whole society started to appreciate the refor-
mation and the high quality of work that still
continues.
But what was the anatomy of this unprec-
edented change? Surely, one person alone, no
matter how good and fast, cannot operate ad-
ditional 1600 patients a year. The size of the
staff has almost tripled since 1997 – today,
the staff includes 16 senior neurosurgeons,
six (nine trainees) residents, 154 nurses and
three OR technicians, in addition to adminis-
trative personnel. The number of ICU beds has
increased from six to 16. The number or OR's
has increased only by one, but the operations
start nowadays earlier, the patient changes are
swift, and there is sufficient staff for longer
workdays. The most significant change, how-
ever, was probably the general increase in the
pace of the operations, mostly because of the
example set by the new chairman, "the fastest
neurosurgeon in the world". The previous rather
conservative treatment policy was replaced by
a very active attitude, and attempts to salvage
also critically ill patients are being made, and
often successfully. Chronological high age per
se is no longer a "red flag" preventing admission
to the Department, if the patient otherwise has
potential for recovery and might benefit from
neurosurgical intervention.
Despite the increased size of staff, the new ef-
ficient approach to doing things meant more
intense and longer workdays. However, perhaps
somewhat surprisingly, the general attitude
among the staff towards these kind of changes
was not only of resistance. The realization of
the outstanding quality and efficiency of the
work the whole team in the Department is do-
ing, has also been the source of deep profes-
sional satisfaction and pride, both among the
neurosurgeons and the nursing staff. An impor-
tant role in the acceptance of all these changes
played also the fact that Prof. Hernesniemi has
always been intensely involved in the daily
clinical work instead of hiding in the corridors
of administrative offices. The price for all this
has not been cheap, of course. The workload,
effort and the hours spent to make all this hap-
pen have been, and continue to be, massive,
and require immense dedication and ambition.
What else has changed? For sure, much more
attention is being paid to the microneurosurgi-
cal technique in all operations. Operations are
faster and cleaner, the blood loss in a typical
operation is minimal, and very little time is
spent on wondering what to do next. Almost
all operations are performed standing, and all
the microscopes are equipped with mouthpiec-

23
es and video cameras to deliver the operative
field view to everybody in the OR. Operative
techniques are taught systematically, starting
from the very basic principles, scrutinized and
analyzed, and published for the global neuro-
surgical community to read and see. Postop-
erative imaging is performed routinely in all
the patients, serving as quality control for our
surgical work. The Department has become
very international. There is a continuous flow
of long- and short-term visitors and fellows,
and the Department is involved in two inter-
national live neurosurgery courses every year.
The staff travels themselves, both to meetings
and to other neurosurgical units, to teach and
to learn from others. The opponents of doctoral
dissertations are among the most famous neu-
rosurgeons in the world. The flow of visitors
may sometimes feel a bit intense, but at the
end of the day makes us proud of the work we
do. The scientific activity has increased signifi-
cantly, and is nowadays well-funded and even
the youngest colleagues can be financially sup-
ported. The visibility of the Department and its
chairman in the Finnish society and the inter-
national neurosurgical community has defi-
nitely brought support along with it.
Overall, the changes during the past two dec-
ades have been so immense that they seem
almost difficult to believe. If there is a lesson
to be learned, it could be this: with sufficient
dedication and endurance in the face of resist-
ance, almost everything is possible. If you truly
believe the change you are trying to make is
for the better, you should stick to it no matter
what, and it will happen.
Table 2-1.
Professors of Neurosurgery in University of Helsinki:
Aarno Snellman 1947-60
Sune Gunnar Lorenz af Björkesten 1963-73
Henry Troupp 1976-94
Juha Hernesniemi 1998-

24
2.2. PRESENT DEPARTMENT SETUP
By 2009, the Department of Neurosurgery
which has an area of only 1562 m2
, utilizing up
to 16 ICU beds, 50 beds on two regular wards
and four operating rooms, was carrying out a
total of 3200 cases per year. Only 60% of pa-
tients are coming for planned surgery and 40%
are coming through the emergency unit. This
means that the care given in all our units is
very acute in nature and the patients often have
their vital and neurological functions threat-
ened. The needed care has to be given fast and
accurately in all units. The department's team
has become successful in setting standards in
quality, efficiency and microneurosurgery, not
just in Nordic countries but worldwide. Often,
patients are sent here from around Europe, and
even from outside Europe, for microneurosurgi-
cal treatment of their aneurysm, AVM or tumor.
The department, managed by Professor and
Chairman Juha Hernesniemi and Nurse Man-
ager Ritva Salmenperä (Figure 2-4), belongs
administratively to Head and Neck Surgery,
which is a part of the operative administrative
section of Helsinki University Central Hospital.
As a university hospital department, it is the
only neurosurgical unit providing neurosurgical
treatment and care for over 2 million people in
the Helsinki metropolitan area and surrounding
Southern and Southeastern Finland. Because of
population responsibility, there is practically no
selection bias for treated neurosurgical cases
and patients remain in follow-up for decades.
These two facts have helped to create some of
the most cited epidemiological follow-up stud-
ies e.g. in aneurysms, AVMs and tumors over the
past decades. In addition to operations and in-
patient care, the department has an outpatient
clinic with two or three neurosurgeons seeing
daily patients coming for follow-up check-ups
or consultations, with approximately 7000 vis-
its per year.
2.3. STAFF MEMBERS
In neurosurgery success is based on team effort.
The team at Helsinki Neurosurgery currently
consists of 16 specialist neurosurgeons, seven
neurosurgical residents, six neuroanesthesi-
ologists, five neuroradiologists, and one neu-
rologist. There are 150 nurses working on the
different wards, four physiotherapists, three
OR technicians, three secretaries and several
research assistants. In addition, we have a very
close collaboration with teams from neuropa-
thology, neuro-oncology, clinical neurophysiol-
ogy, endocrinology and both adult and pediat-
ric neurology.
Figure 2-4. Nurse Manager Ritva Salmenperä
2 | Present department setup

25
Neurosurgeons | Staff members | 2
2.3.1. Neurosurgeons
At the beginning of the year 2010 there were
16 board certified neurosurgeons and one neu-
rologist working at Helsinki Neurosurgery:
Juha Hernesniemi, MD, PhD
Professor of Neurosurgery and Chairman
MD: 1973, University of Zürich, Switzerland;
PhD: 1979, University of Helsinki, Finland,
"An Analysis of Outcome for Head-injured Pa-
tients with Poor Prognosis"; Board certified
neurosurgeon: 1979, University of Helsinki,
Finland; Clinical interests: Cerebrovascular
surgery, skull base and brain tumors; Areas of
publications: Neurovascular disorders, brain
tumors, neurosurgical techniques.
Jussi Antinheimo, MD, PhD
Staff neurosurgeon
MD: 1994, University of Helsinki, Finland; PhD:
2000, University of Helsinki, Finland, "Meningi-
omas and Schwannomas in Neurofibromatosis
2"; Board certified neurosurgeon: 2001, Uni-
versity of Helsinki, Finland; Clinical interests:
Complex spine surgery; Areas of publications:
Neurofibromatosis type 2.
Göran Blomstedt, MD, PhD
Associate Professor, Vice Chairman,
Head of section (Outpatient clinic)
1986, University of Helsinki, Finland, "Postop-
erative infections in neurosurgery"; Board cer-
tified neurosurgeon: 1981, University of Hel-
sinki, Finland; Clinical interests: Brain tumors,
vestibular schwannomas, epilepsy surgery,
peripheral nerve surgery; Areas of publication:
Neurosurgical infections, brain tumors, epi-
lepsy surgery.

26
Atte Karppinen, MD
Staff neurosurgeon
MD: 1995, University of Helsinki, Finland;
Board certified neurosurgeon: 2003, University
of Helsinki, Finland; Clinical interests: Pediatric
neurosurgery, epilepsy surgery, pituitary sur-
gery, neuroendoscopy.
Leena Kivipelto, MD, PhD
Staff neurosurgeon
1991, University of Helsinki, Finland, "Neu-
ropeptide FF, a morphine-modulating peptide
in the central nervous system of rats"; Board
certified neurosurgeon: 1996, University of
Helsinki, Finland; Clinical interests: Cerebrov-
ascular surgery, bypass surgery, pituitary sur-
gery, spine surgery; Areas of publications:
Neuropeptides of central neurvous system,
neuro-oncology.
Riku Kivisaari, MD, PhD
Assistant Professor
2008, University of Helsinki, Finland, "Radio-
logical imaging after microsurgery for intrac-
ranial aneurysms"; Board certified radiologist:
2003, University of Helsinki, Finland; Board
Helsinki, Finland; Clinical interests: Endovascu-
lar surgery, cerebrovascular diseases ; Areas of
publications: Subarachnoid hemorrhage, cer-
ebral aneurysms.
2 | Staff members | Neurosurgeons

27
Miikka Korja, MD, PhD
Staff neurosurgeon
MD: 1998, University of Turku, Finland; PhD:
2009, University of Turku, Finland, "Molecular
characteristics of neuroblastoma with special
reference to novel prognostic factors and diag-
nostic applications"; Board certified neuro-
surgeon: 2010, University of Helsinki, Finland;
Clinical interests: Cerebrovascular surgery,
functional neurosurgery, skull base surgery,
neuroendoscopy; Areas of publications: Tumor
biology, subarachnoid hemorrhage, neuroimag-
ing, bypass surgery.
Aki Laakso, MD, PhD
Staff neurosurgeon, Associate Professor
in Neurobiology
1999, University of Turku, Finland, "Dopamine
Transporter in Schizophrenia. A Positron Emis-
sion Tomographic Study"; Board certified
Finland; Clinical interests: Cerebrovascular dis-
eases, neuro-oncology, neurotrauma, neuroin-
tensive care; Areas of publications: Brain AVMs
and aneurysms, basic neuroscience.
Martin Lehecka, MD, PhD
Staff neurosurgeon
2009, University of Helsinki, Finland, "Distal
Anterior Cerebral Artery Aneurysms"; Board
Helsinki, Finland; Clinical interests: Cerebrov-
ascular surgery, bypass surgery, skull base and
brain tumors, neuroendoscopy; Areas of publi-
cations: Cerebrovascular diseases, microneuro-
surgical techniques.

28
Mika Niemelä, MD, PhD
Associate Professor, Head of section
(Neurosurgical OR)
MD: 1989, Univeristy of Helsinki, Finland; PhD:
2000, Univeristy of Helsinki, Finland, "Heman-
gioblastomas of the CNS and retina: impact
of von Hippel-Lindau disease"; Board certified
Finland; Clinical interests: Cerebrovascular
diseases, skull base and brain tumors; Areas of
publications: Cerebrovascular disorders, brain
tumors, basic research on aneurysm wall and
genetics of intracranial aneurysms.
Minna Oinas, MD, PhD
Staff neurosurgeon
2009,UniversityofHelsinki,Finland,"α-Synuclein
pathology in very elderly Finns"; Board certified
neurosurgeon: 2008, University of Helsinki, Fin-
land; Clinical interests: Pediatric neurosurgery,
skull base and brain tumors; Area of publica-
tions: Neurodegenerative diseases, tumors.
Juha Pohjola, MD
Staff neurosurgeon
MD: 1975, University of Zürich, Switzerland;
of Helsinki, Finland; Clinical interests: Complex
spine surgery, functional neurosurgery.
Esa-Pekka Pälvimäki, MD, PhD
Staff neurosurgeon
1999, University of Turku, Finland, "Interac-
tions of Antidepressant Drugs with Serotonin
5-HT2C Receptors."; Board certified neuro-
Clinical interests: Spine surgery, functional
neurosurgery; Areas of publications: Neurop-
harmacology, functional neurosurgery.
2 | Staff members | Neurosurgeons

29
Jari Siironen, MD, PhD
Associate Professor, Head of section (ICU)
1995, University of Turku, Finland, "Axonal reg-
ulation of connective tissue during peripheral
nerve injury"; Board certified neurosurgeon:
2002, University of Helsinki, Finland; Clinical
interests: Neurotrauma, neurointensive care,
spine surgery; Areas of publications: Subarach-
noid hemorrhage, neurotrauma, neurointensive
care.
Matti Seppälä, MD, PhD
Staff neurosurgeon
1998, University of Helsinki, Finland, "Long-
term outcome of surgery for spinal nerve sheath
neoplasms"; Board certified neurosurgeon:
1990, University of Helsinki, Finland; Clinical
interests: Neuro-oncology, radiosurgery, spine
surgery; Areas of publications: Neuro-oncolo-
gy, neurotrauma, spine surgery.
Matti Wäänänen, MD
Staff neurosurgeon
MD: 1980, University of Kuopio, Finland; Board
certified general surgeon: 1986, University of
Kuopio, Finland; Board certified orthopedic
of Helsinki, Finland; Clinical interests: Complex
spine surgery, peripheral nerve surgery.
Maija Haanpää, MD, PhD
Associate Professor in Neurology
MD: 1985, University of Kuopio, Finland; PhD:
2000, University of Tampere, Finland, "Herpes
zoster – clinical, neurophysiological, neurora-
diological and neurovirological study"; Board
certified neurologist: 1994, University of Tam-
pere, Finland; Clinical interests: Chronic pain
management, neurorehabilitation, headache;
Areas of publications: Pain management, neu-
ropathic pain, neurorehabilitation.

30
Figure 2-22. Neuroanesthesiologists at Töölö Hospital. Back: Marja Silvasti-Lundell, Juha Kyttä, Markku Määttänen, Päivi
Tanskanen, Tarja Randell, Juhani Haasio, Teemu Luostarinen. Front: Hanna Tuominen, Ann-Christine Lindroos, Tomi Niemi
2 | Staff members | Neurosurgical residents | Neuroanesthesiologist
2.3.2. Neurosurgical residents
There are currently nine neurosurgical residents
in different phases of their 6-year neurosurgi-
cal training program:
Juhana Frösén, MD, PhD
Emilia Gaal, MD
Antti Huotarinen, MD
Juri Kivelev, MD
Päivi Koroknay-Pál, MD, PhD
Hanna Lehto, MD
Johan Marjamaa, MD, PhD
Anna Piippo, MD
Julio Resendiz-Nieves, MD, PhD
2.3.3. Neuroanesthesiologists
The team of anesthesiologists at Helsinki Neu-
rosurgery, six of them specialists in neuroan-
esthesia, is led by Associate Professor Tomi
Niemi. In addition there are usually a couple
of residents or younger colleagues in training.
During daytime four of the anesthesiologists
are assigned to the OR's and two work at the
neurosurgical ICU. Collaboration between an-
esthesiologists and neurosurgeons is very close
both in and out of the OR. There are joined
rounds at the ICU twice a day.
Tomi Niemi, MD, PhD
Hanna Tuominen, MD, PhD
Juha Kyttä, MD, PhD (1946-2010)
Juhani Haasio, MD, PhD
Marja Silvasti-Lundell, MD, PhD
Markku Määttänen, MD
Päivi Tanskanen, MD
Tarja Randell, MD, PhD

31
Figure 2-23. Neuroradiologists at Töölö Hospital. From left: Kristiina Poussa, Jussi Laalo, Marko Kangasniemi,
Jussi Numminen, Goran Mahmood.
Neuroradiologists | Staff members | 2
2.3.4. Neuroradiologists
A dedicated team of five neuroradiologists and
one or two residents or younger colleagues is
lead by Associate Professor Marko Kangasnie-
mi. The neuroradiological team is taking care
of all the neuroimaging. That includes CT, MRI,
and DSA imaging. Endovascular procedures are
carried out in a dedicated angio suite by neuro-
radiologists in close collaboration with neuro-
surgeons. Every morning at 08:30 AM there is
a joined neuroradiological meeting that is at-
tended by all the neurosurgeons and the neu-
roradiologists.
Marko Kangasniemi, MD, PhD
Jussi Laalo, MD
Jussi Numminen, MD, PhD
Johanna Pekkola, MD, PhD
Kristiina Poussa, MD

32
2 | Staff members | Bed wards
Figure 2-24. Staff of bed ward No. 6, with head nurse Marjaana Peittola (sitting, second from right)
2.3.5. Bed wards
The department of neurosurgery has a total of
50 beds in two wards. Of the 50 beds, seven are
intermediate care beds and 43 unmonitored
general beds. In addition, there are two isola-
tion rooms. The isolation rooms are equipped
with full monitoring possibilities and can be
used for intensive care purposes as well, if
needed.
Patients coming for minor operations, for ex-
ample spinal surgery, usually spend relatively
short time on the ward, 1-2 days after opera-
tion before being discharged. Patients coming
for major surgery, for example brain tumor or
unruptured aneurysm, stay for 5 to 8 days, and
emergency patients recovering from severe
disease or brain injury can stay in the depart-
ment for up to 2 months. Average stay for all
patients is 4.6 days.
The staff at bed wards consists of one head
nurse at each ward, nursing staff of 45 nurses
and 3 secretaries. There are two physiothera-
pists present at both wards and ICU. The staff
is professional and motivated in their work.
One of the main duties for ward nurses is to
perform neurological assessment and register
findings so that the continuity of care is en-
sured. They also take care of medication, nu-
trition and electrolyte balance, interview pa-
tients for health history, perform wound care
and stitch removal, give information and home
instructions and educate the patients.
The intermediate care room is meant for pa-
tients who still require ventilator support but
do no longer fulfill the criteria for intensive
care treatment. Typical patients are recovering
from severe head trauma or acute hemorrhagic

33
Bed wards | Staff members | 2
Figure 2-25. Staff of bed ward No. 7, with head nurse Päivi Takala (left)
stroke. Patients can have problems with breath-
ing, still need respiratory care, have problems
with nutrition, anxiety and pain; all this care is
given by our staff nurses. There are one or two
nurses present at all times. When needed, the
nurses alert also neurosurgeons and anesthesi-
ologists based on their observations. The nurses
in the two wards rotate in intermediate care
room so that everyone is able to take care of
all critically ill patients.

34
2 | Staff members | Intensive care unit (ICU)
Figure 2-26. Staff of ICU, with head nurse Petra Ylikukkonen (front row, third from left).
2.3.6. Intensive care unit (ICU)
The neurosurgical ICU has 14 beds and two re-
covery beds for patients with minor operations
who only need a couple of hours of monitor-
ing and observation. Additionally, there are
two isolation rooms for severe infections, or
patients coming for treatment from outside of
Scandinavia (to prevent spread of multiresist-
ent micro-organisms). The staff consists of the
head nurse, 59 nurses and a ward secretary. In
the ICU one nurse is usually taking care of two
patients with some exceptions. Small children
and parents have special needs and have their
own nurse. Critically ill and unstable patients,
e.g. high intracranial pressure or organ donor
patients also have their own nurse.
All patients undergoing surgery are treated in
the ICU that also functions as a recovery room.
In 2009, 3050 patients were treated in the ICU.
Half of the patients stay at the ICU for less than
6 hours recovering from surgery. Intensive care
nurses take care of patient monitoring and do
the hourly neurological assessment. Monitor-
ing includes for example vital signs, pCO2
, GCS,
SvjO2
, EEG, intracranial pressure and cerebral
perfusion pressure, depending on the patient's
needs. Nurses also take care of pain and anxiety
relief. Neurosurgeons make the majority of the
decisions concerning patient care, discuss with
the patient and family members, make notes to
the charts and perform required bedside sur-
gical interventions, such as percutaneous tra-
cheostomies, ventriculostomies and implanting
ICP monitoring devices. Neuroanesthesiologists
are in charge of medication, respiratory man-
agement, nutrition and monitoring of labora-
tory parameters. Joint rounds between neuro-
surgeons, neuroanesthesiologists and nurses
take place twice a day, in the morning and in
the afternoon. The multidisciplinary team also
includes physiotherapists and, when needed,
consultants of different disciplines, like infec-
tious diseases and orthopedic, maxillofacial
and plastic surgery.

35
Intensive care unit (ICU) | Staff members | 2
The ICU is a very technical environment with
electronic patient files and computerized data
collection. ICU nurses have to provide safe and
continuous care to the patient who is facing
an acute, life-threatening illness or injury. De-
pending on the nurse's previous background
and experience, the critical care orientation
program takes 3-5 weeks of individual train-
ing with preceptors, and after that the amount
of more independent work increases gradually.
Critically ill patients, organ donors and small
children are allocated to nurses only after he or
she has sufficient experience in common proce-
dures and protocols. The last step after two or
three years of experience is to work as a team
leader during the shift, i.e. the nurse in charge.
Nurses in the ICU perform strenuous shift work
and many prefer working long shifts of 12.5
hours, which gives them the opportunity to
have more days off than working the normal 8
hour shift. ICU nurses have autonomy in plan-
ning the shifts, making it easier to accommo-
date work and personal life. This principle of
planning the working hours is the same in all
units, but it works especially well in the ICU
where the staff is quite large.

36
Figure 2-27. Operating room staff, with head of section Dr. Mika Niemelä (standing in the back), head nurse Saara Vierula
(front row, first from right) and head nurse Marjatta Vasama (front row, fourth from right).
2 | Staff members | Operating rooms
2.3.7. Operating rooms
The four OR's are located in a recently reno-
vated and redecorated area. It gives a nice
surrounding for a work that in many aspects
is very technical and demanding. The focus
of nursing care in the OR is to treat patients
safely and individually, even though emergency
situations may require such rapid thinking and
decision-making that things may almost ap-
pear to happen by themselves.
There are two head nurses (surgical and an-
esthesiological), 28 nurses and three OR tech-
nicians working in four OR's. Nurses are divided
into two groups: scrub nurses and neuroan-
esthesiological nurses. Nurses are working in
two shifts, and two scrub nurses and one an-
esthesiological nurse are on call starting from
8 PM to 8 AM. Because almost half of our pa-
tients are emergency patients, the active work-
ing hours for those on call usually continues
until midnight or later, and the next day is free.
During weekends the nurses are also on call,
and two teams share one weekend.
The staff is relatively small, the work in neu-
rosurgical OR is highly specialized, and the
familiarization and orientation takes several
months under the supervision of the precep-
tor. The tasks of scrub nurses include patient
positioning (done together with technicians,
the neurosurgeon and the anesthesiologist),
the skin preparation, draping, instrumentation,
and dressing. Anesthesiological nurses do the
preparations for anesthesia and intraoperative
monitoring and take care of reporting and doc-
umentation. Anesthesiological nurses also take
patients to neuroradiological examinations and
interventions and take care of and monitor pa-
tients during these procedures.
Work rotation is encouraged between all units.
After a couple of years of concentrating ei-
ther on anesthesia or instrumentation we try
to encourage the nurses, who are interested
in expanding their knowledge and skills, to be
able to work both as an scrub nurse and an
anesthesiological nurse. There is also work ro-

37
Fig 2-28. Administrative assistants Heli Holmström, Eveliina Salminen and Virpi Hakala.
Administrative personnel | Staff members | 2
tation between ICU and OR, ICU and bed wards,
and we have nurses who have been working in
all three units.
Nursing students are trained continuously in all
units. Special attention is paid to inspire an in-
terest in neurosurgery in them, since they might
be our future employees. We hope that both
students and our nurses approach neurosurgical
nursing from a perspective of career rather than
merely a job. This can result in a high level of
satisfaction and more options for professional
advancement. There is a well-established co-
operation with Finnish Association of Neuro-
science Nurses (FANN), European Association of
Neuroscience Nurses (EANN) and World Federa-
tion of Neuroscience Nurses (WFNN). This gives
an opportunity to do national and international
co-operation and gives possibilities to attend
meetings, meet colleagues in the same field and
visit other interesting neurosurgerical depart-
ments in world in the same way as many visi-
tors are attending our department nowadays.
2.3.8. Administrative personnel
A small but absolutely invaluable part of the
Department's personnel is found on the ad-
ministrative floor, where three administrative
assistants, Virpi Hakala, Eveliina Salminen and
Heli Holmström, take care of myriads of things
to ensure e.g. that patient referral letters are
handled reliably and in timely fashion, the
whole staff gets their paychecks, needs of for-
eign visitors are accommodated, Prof. Hernes-
niemi's flight tickets and hotel reservations are
up-to-date despite last minute changes of an
extremely busy schedule… In other words, this
is work that you may not appreciate enough
because these things are managed so smoothly
and professionally "behind the scenes" that you
do not even realize the immense workload re-
quired to keep the wheels of the Department
lubricated – unless there would be a glitch and
nothing would work anymore!

38
Fig 2-29. Overview of the OR1
2 | Operating room complex

40
2.4. OPERATING ROOM COMPLEX
2.4.1. Operating room complex design
The OR complex in Helsinki is dedicated solely to
neurosurgery. It has four separate OR's arranged
in semicircular fashion. The whole complex was
refurbished in 2005 according to the needs of
modern microneurosurgery, with emphasis on
efficient workflow, open and inviting atmos-
phere, and teaching with high quality audio-
visual equipment. Besides the actual OR's, the
complex includes also storage rooms, offices for
anesthesiologists and nursing staff, a meeting
room with library and an auditorium in the lob-
by of the complex. The setup in each of the OR's
is similar and equipment can be easily moved
from one room to the other. From each OR live
video image can be displayed on big screen in
the lobby. All OR's are used every day from 8 AM
to 3 PM, one OR is open until 6 PM and one OR
is used around the clock for emergency cases.
The operating room in Helsinki is also the anes-
thetic room. Some other countries and institu-
tions have them separate. The advantage of us-
ing the same room is the avoidance of patient
transfer and the inherent risks associated with
this. The disadvantage is that the room has to
have the appropriate space, storage, equip-
ment, and ambience for both functions. In our
experience, the time that is saved by having a
separate anesthetic room is very limited com-
pared to the length of the actual procedure,
transferring the patient and the time spent re-
connecting all the necessary cables and lines.
After trying both options, we have settled for
handling the whole anesthesia and patient po-
sitioning inside the operating room.

41
Operating room complex | 2
2.4.2. Operating room ambience
The atmosphere in any OR, let alone one where
modern microneurosurgery is performed, may
well be crucial for the difference between suc-
cess and failure in the operation. Mutual re-
spect between all members in the team is a
key factor in creating a successful ambience.
We also feel that it is a great asset that the
nurses are dedicated to and very experienced
in neurosurgical operations – often the cor-
rect instrument is handed over to the surgeon
immediately without a need to say a word.
Since working atmosphere and ambience may
be difficult to evaluate from within the team
(especially if it is good!), a testimony from a
visitor with a wider perspective may elucidate
the situation better. In the following, Dr. Man-
soor Foroughi has described his observations
and feelings:
"It is said that the ideal socialist health care
system provides the best health care at the
lowest cost! In the Helsinki experience and the
school of Juha Hernesniemi there are other ma-
jor staff factors, which are included in the ideal
health care system besides financial cost! These
are a sense of professionalism, being valued,
worker dignity, morale, sense of belonging to a
greater good, solidarity and general happiness
and welfare. These factors are not easily com-
promised on or sacrificed for a lower cost! The
professionals that work here are easily worth
more than their weight in gold. They seem to
be happy here despite the heavy workload and
number of visitors. This is in comparison to oth-
er places visited. Without a doubt they deserve
more money and greater financial incentives
than that we have been informed they get. We
hope all societies reward those that work hard,
train long and acquire special skills!"
"Several members of the staff repeat the story
of how they moved from place to place and
then ended up staying here as they really liked
it. The reasons seem to be the following:
- They feel valued and appreciated. The
surgeon habitually and genuinely thanks
the theatre staff, especially after a difficult
or long case. They are always listened to and
their wishes and concerns noted. Whether it
would be about lack of a piece of equipment
or the choice of music in theatre. The scrub
nurses look forward to the gentle nudge or
other gestures of appreciation from Juha
after a difficult or complex case. They clearly
feel they are making a difference. So they
pass the instruments with accuracy and
efficiency, listen attentively, set up equip-
ment promptly on demand, observe closely
(using the excellent audiovisual equipment
provided in theatre), operate the bipolar
pedal with unerring calm & accuracy, follow
the suture during closure and apply dress-
ings. In general they want be involved a lot
probably because they feel they are valued
and making a difference.
- Professionalism and code of conduct. None
of the fellows have ever witnessed on any
occasion any suggestion or sign of rude or
lewd behavior, loss of temper, shouting,
intimidation, crying, obvious mental distress
or bad conduct. This is most unusual for
some visitors who are culturally or tradi-
tionally used to and accept the disturbing
chat in theatre and even shouting. Some
visitors accept the expressions of the surgi-
cal "artistic temperament" as normal every-
day life.On the other hand we have never
seen a frustrated or distressed surgeon
because equipment is not available, or an
instrument is not passed, or the bipolar is

42
not on or off at the appropriate time, or the
nursing staff question the validity of a
request for a laborious tool or an expensive
item. What is needed is asked for by the
surgeon, and it is immediately and efficient-
ly provided!"
"It is hard to quantify happiness at work in a
business plan, or highlight the importance of
welfare for staff using some kind of scoring
system or study. But if you visit Helsinki and
spend sometime talking to the staff, you will
come to know that they are generally content,
and their performance is excellent because they
are happy at work and happy with their leader!
This is an example to the world."
"This is a place of order, peace, focus and pro-
fessionalism. The anesthetist, surgeon, nursing
staff and assistants all need to communicate.
There should however be great consideration,
respect and courtesy towards a neurosurgeon
who is carrying out microneurosurgery in some-
one's brain. His or her senses are heightened
and consequently the surgeon is very sensitive
to the surroundings. Sudden interruptions, loud
noises, audible telephone conversations and
the rising volume of background chat can be
dangerous. All such noises are discouraged and
handled politely but appropriately. However a
feeling of fear, anxiety and tension is also not
appreciated or conducive for morale and wel-
fare of staff, especially if the aim is to do good
long term. All are generally calm, respectful and
avoid commotion. There is no disturbing chat in
the theatre complex in Helsinki no matter who
is operating. You really feel the difference and
contrast between the Nordic calm and profes-
sionalism and for example the Latino expres-
sion of emotion and commotion. If you want to
be able to focus and encourage good surgery
as a team, then learn from the Helsinki theatre
ambience. All must be calm and respectful, but
allowed basic freedoms. Basic freedoms mean
to come and go very quietly, be seated or stand
comfortably and be allowed a good view of the
surgery. At all times there is great consideration
and respect for the team and the patient whom
all are there to serve!"
"Some theatres ban the use of music but in
Juha's theatre there is one radio station chosen
for its neutral soft background music. This
relaxes the staff and lessens any possible ten-
sion felt in theatre. If the surgeon, anesthetist
or scrub nurse wish to turn this off or down,
they can. The staff clearly appreciate this music,
and many have stated that it relaxes them. The
choice of the station is limited to one Finn-
ish language station. The radio is switched off
when there is extreme concentration, as well as
immediate action and reaction needed from the
team. This may be during temporary clipping
or when there is haemorrhage from a ruptured
aneurysm. Some visitors and especially fellows
have had the same tunes, songs and even
adverts imprinted in their memory while they
were closely observing masterful surgery. Until
they have learned how to listen and how not to
listen! The surgeon they come to see is calmed
by the music, but mostly seems to switch off to
the music. He isolates himself from the world,
and lives in the moment of surgery. There is a
lesson on how to train yourself and compromise
with your senses and those around you."

45
Anesthesia | 3
3. ANESTHESIA
by Tomi Niemi, Päivi Tanskanen and Tarja Randell
In Helsinki University Central Hospital, the De-
partment of Neuroanesthesia in Töölö Hospi-
tal has six neuroanesthesiologists. Daily four
anesthesiologists of whom at least two are
specialized in neuroanesthesia, work in the
neurosurgical OR's and in the radiology suite,
and two (at least one of them specialized in
neuroanesthesia) at the neurosurgical ICU, and
in the emergency room (ER) when needed. The
perioperative anesthesia care includes preoper-
ative assessment, management of the patients
in the OR, and postoperative care in the ICU
and also at the wards as required. In addition,
one of three anesthesiologists who are on call
in the hospital overnight is assigned to neu-
roanesthesia and neurointensive care.
In the Finnish system, the neuroanesthesia
nurses are trained to take care of the patients
in the OR, and also in the radiology suite, ac-
cording to the clinical protocol and individual
anesthesiologist's instructions. The anesthe-
siological nurses assist anesthesiologists in the
induction of anesthesia, and during emergence;
also, the anesthesiologist is always present dur-
ing positioning. The maintenance of anesthesia
is usually managed by the nurse, but the an-
esthesiologist is always available, and present
if clinically required.
The principles of neuroanesthesia are based
on general knowledge of cerebral blood flow
(CBF), cerebral perfusion pressure (CPP), cere-
bral carbon dioxide (CO2
) reactivity, and meta-
bolic coupling, none of which can be continu-
ously monitored during routine anesthesia. We
base our clinical practice on the assumption
that in most patients scheduled for craniotomy
irrespective of the indication, the intracranial
pressure (ICP) is on the steep part of the ICP-
compliance-curve, with minimal reserve to
compensate for any increases in the pressure
(Figure 3-1). However, once the dura is opened,
ICP is considered to be zero and mean arterial
pressure (MAP) equals CPP. The anesthesiolo-
gists must estimate these physiological princi-
ples according to the pathology of the central
nervous system (CNS) before and during each
anesthesia and he or she must understand the
effects of all the perioperatively used drugs on
them.
The objective of neuroanesthesia is to main-
tain optimal perfusion and oxygen delivery to
the CNS during the treatment. Intraoperatively,
we aim to provide good surgical conditions,
i.e. slack brain, by means of various methods
at our disposal (Table 3-1). Neurophysiologic
monitoring during certain operations presents
a challenge, knowing that most anesthesia
agents interfere with monitoring of electrone-
uromyography (ENMG), evoked potentials and
electroencephalography (EEG). Finally, we want
to believe that our anesthesiological practice
provides neuroprotection although there is no
strong scientific evidence to support this idea
in humans.
ICP
Intracranial volume
V1 V2
P2
P1
Figure 3-1. Intracranial pressure (ICP)-compliance curve
indicating the relation of intracranial volume and ICP. On
the steep part of the ICP-compliance-curve, the patient has
minimal reserve to compensate for any increases in the ICP
Neuroanesthesiologist Hanna Tuominen, MD, PhD

46
3 | Anesthesia | General physiological principles
3.1. GENERAL PHYSIOLOGICAL PRINCIPLES
AND THEIR IMPACT ON ANESTHESIA
3.1.1. Intracranial pressure
The rigid cranium presents a challenge to our
clinical practice in neuroanesthesia, especially
when the compensatory mechanisms seem
to be limited in acute changes of the intrac-
ranial volume. Translocation of cerebrospinal
fluid (CSF) to the spinal subarachnoid space,
or reduction of the intracranial arterial blood
volume by optimizing arterial CO2
tension, or
ensuring cerebral venous return by optimal
head position and elevation above chest level,
or osmotherapy may create more space prior to
surgical removal of an intracranial space oc-
cupying lesion.
All inhalation anesthetics are potent cerebral
vasodilators, and without concomitant mild
hyperventilation they may cause significant
increases in the ICP, when the compensatory
mechanisms are exhausted. Therefore, induc-
tion of anesthesia with inhalation anesthetics
is contraindicated in our department, especially
because normoventilation or mild hyperventila-
tion cannot be ensured during this critical phase
of anesthesia. Also, induction would require a
concentration of anesthetic that exceeds the 1
MAC (minimum alveolar concentration) upper
limit (see below). In patients with space oc-
cupying intracranial lesions with verified high
ICP, or brain swelling during surgery, propofol is
used for the maintenance of anesthesia, after
the induction with thiopental. Inhalation anes-
thetics are contraindicated in such a situation.
Propofol is known to decrease ICP, so whenever
propofol infusion is used, hyperventilation is
contraindicated. Nitrous oxide (N2
O) is known
to diffuse into air-containing spaces, resulting
in their expansion, or in case of non-compliant
space, in increased pressure. Therefore, N2
O is
contraindicated in patients who have under-
gone previous craniotomy within two weeks, or
who show intracranial air on the preoperative
CT-scan. In these patients the use of N2
O could
result in increase of the ICP due to enlarge-
ment of intracranial air bubbles.
Positioning
Head 15–20 cm above heart level in all positions
Excessive head flexion or rotation is avoided  ensures
good venous return
Osmotherapy
One of the three options below, given early enough before
dura is opened
Mannitol 1g/kg i.v.
Furosemide 10–20 mg i.v. + mannitol 0.25–0.5 g/kg i.v.
NaCl 7.6% 100 ml i.v.
Choice of anesthetics
High ICP anticipated  Propofol infusion without N2
O
Normal ICP  Propofol infusion or volatile anesthetics
(sevoflurane/isoflurane ± N2
O)
Ventilation and blood pressure
No hypertension
Mild hyperventilation
Note! With volatile anesthetics, hyperventilate up to
PaCO2
= 4.0–4.5kPa
CSF drainage
Lumbar drain in lateral park bench position
Release of CSF from cisterns or third ventricle through
lamina terminalis intraoperatively
EVD if difficult access to cisterns
Table 3-1. Helsinki concept of slack brain during craniotomy

47
General physiological principles | Anesthesia | 3
3.1.2. Autoregulation of cerebral blood flow
Adequacy of the CPP must be assessed individu-
ally. CBF autoregulation is absent, or disturbed,
at least locally in most neurosurgical patients,
so that CBF becomes linearly associated with
systemic arterial blood pressure (Figure 3-2).
In addition, the CBF-CPP-autoregulation curve
may also be shifted either to the right (espe-
cially in subarachnoid hemorrhage patients), or
to the left (in children or in arteriovenous mal-
formation patients), implying respective higher
or lower CPP requirements to ensure adequate
CBF (Figure 3-3). Furthermore, increased sym-
pathetic activity, chronic hypertension, liver
dysfunction, infection or diabetes may disturb
CBF autoregulation.
CBF(ml/100g/min)
100
50
0
CPP (mmHg)
Normal
Absent
0 50 100 150
Figure 3-2. Normal or absent autoregulation of cerebral
blood flow (CBF). CPP, cerebral perfusion pressure
The limits of autoregulation are estimated by
assessing the effect of increase, or decrease, in
MAP on CBF by means of ICP (or CBF) measure-
ment. The static autoregulation is expressed as
the percentage change of ICP (or CBF) related
to the change of MAP over the predetermined
interval. The dynamic autoregulation indicates
the rate (in seconds) of response of the change
in ICP (or CBF) to the rapid change in MAP. As
the presence of intact autoregulation or the
limits of autoregulation cannot be estimated
in routine anesthesia practice, we must rely on
the assumption of its state. In patients with
SAH, or acute brain injury, autoregulation may
be disturbed or absent altogether, whereas, in
some other neurosurgical patients it may be
normal. As a result, normotension or estimated
CPP of 60 mmHg or higher is the goal of our
treatment. In SAH patients the lower limit of
autoregulation may be much higher.
The volatile anesthetics are known to impair
autoregulation in a dose-dependent fashion,
whereas intravenous agents generally do not
have this effect. Isoflurane and sevoflurane can
be administered up to 1.0 and 1.5 MAC respec-
tively, whereas desflurane impairs autoregula-
tion already in 0.5 MAC. Therefore, isoflurane
and sevoflurane are suitable for neuroanesthe-
sia, and can be delivered either in oxygen-N2
O
mixture or in oxygen-air mixture. When N2
O is
used, the targeted anesthetic depth is achieved
with smaller gas concentrations than without
N2
O. Bearing in mind that high concentrations
of all inhaled anesthetics may evoke general-
ized epileptic activity, adding N2
O to the gas ad-
mixture seems advantageous. The pros and cons
of N2
O are also discussed in section 3.4. For
sevoflurane, it is not recommended to exceed
3% inhaled concentration in neuroanesthesia.
CBF(ml/100g/min)
100
50
0
CPP (mmHg)
?
Increased sympathetic activity
Chronic hypertension
SAH
AVM
Normal
0 50 100 150
Figure 3-3. The assumed shift of the cerebral blood flow
(CBF)- cerebral perfusion pressure (CPP)-autoregulation
curve in subarachnoid hemorrhage (SAH) or in arteriove-
nous malformation (AVM) patients. The safe limits of the
CPP must be assessed individually

48
3 | Anesthesia | General physiological principles
3.1.3. CO2
reactivity
The second clinically important factor regulat-
ing CBF is arterial CO2
tension (PaCO2
) (cerebral
CO2
reactivity). We generally normoventilate
the patients during anesthesia. In patients
with high intracranial pressure (ICP) or severe
brain swelling, we may use slight hyperven-
tilation, but in order to avoid brain ischemia
PaCO2
should not be allowed to decrease below
4.0 kPa. When even lower PaCO2
is needed in
the ICU, global cerebral oxygenation should be
monitored by brain tissue oxygen tension to
detect possible excessive vasoconstriction in-
duced ischemia. In clinical practice it is of ut-
most importance to highlight the impairment
of cerebral CO2
reactivity during hypotension
(Figure 3-4). The reactions of hypercapnia-
induced cerebral vasodilatation (CBF, ICP) or
hypocapnia-induced cerebral vasoconstriction
(CBF, ICP) are impaired if the patient has hy-
potension. Thus, CBF and ICP may remain un-
changed although PaCO2
tension is modified in
hypotensive patients. In contrast to the effect
of PaCO2
on CBF, the PaO2
does not affect on
CBF if PaO2
is above 8 kPa, which is the criti-
cal level for hypoxemia. A powerful increase in
CBF is seen when PaO2
is extremely low, e.g. <
6.0 kPa.
While CO2
reactivity is disturbed by vari-
ous pathological states, it is rather resistant
to anesthetic agents. In patients with an in-
creased ICP or those with limited reserve for
compensation, even modest increases of PaCO2
may cause marked further increase in the ICP.
Therefore, periods without ventilation must be
kept as short as possible, for instance during
intubation or awakening. As a categorical rule
for craniotomy patients, hypoventilation must
be avoided during awakening, because possible
postoperative intracranial bleeding together
with increased PaCO2
may result in a detrimen-
tal increase in ICP.
120
80
40
0
-40
RelativechangeinCBF(%)
1.5 6.5 10
PaCO 2 (kPa)
MAP
80 mmHg
50 mmHg
30 mmHg
4.0
Figure 3-4. The effect of arterial carbon dioxide tension
(PaCO2
) on cerebral blood flow (CBF) at various mean arteri-
al pressure (MAP) levels

49
General physiological principles | Anesthesia | 3
3.1.4. Cerebral metabolic coupling
The third clinically important neuroanesthe-
siological aspect is cerebral metabolic coupling
(Table 3-2). CBF is regulated by the metabolic
requirements of brain tissue (brain activation
CBF, rest or sleep CBF). Of brain cell metabo-
lism, 40-50% is derived from basal cell metab-
olism and 50-60% from electrical activity. The
electrical activity can be abolished by anes-
thetic agents (thiopental, propofol, sevoflurane,
isoflurane), but only hypothermia can decrease
both the electrical activity and the basal cell
metabolism. Propofol seems to preserve cou-
pling, but volatile agents do not. N2
O seems to
attenuate the disturbance. Impaired coupling
results in CBF exceeding the metabolic demand
(luxury perfusion).
CMRO2 CBF ICP vasodilatation
Isoflurane   (*)  (*) +
Sevoflurane   (*)  (*) +
N2
O    +
Thiopental    -
Propofol    -
Midazolam    -
Etomidate    -
Droperidol    -
Ketamine    +
*with mild hyperventilation
Table 3-2. The effects of anesthetic agents on cerebral metabolic rate for oxygen (CMRO2)
cerebral blood flow (CBF), intracranial pressure (ICP) and cerebral arterial vasodilatation.

50
3 | Monitoring of anesthesia
Table 3-3. Routine monitoring for craniotomy
• ECG
• Invasive blood pressure (zeroed at the level
of Foramen Monroe)
• SpO2
• EtCO2
• Side stream spirometry, airway gas monitoring
• Hourly urine output
• Core temperature
• Neuromuscular blockade
• CVP and cardiac output (with PICCO™ or Vigileo™)
– not monitored routinely*
* only in major bypass surgery, in microvascular free
flaps in skull base surgery or if medically indicated.
3.2. MONITORING OF ANESTHESIA
Routine monitoring in neuroanesthesia in-
cludes heart rate, ECG (lead II with or with-
out lead V5), peripheral oxygen saturation, and
non-invasive arterial blood pressure before
invasive monitoring is commenced (Table 3-3).
A radial or femoral arterial cannula is inserted
for direct blood pressure measurements in all
craniotomy patients or whenever the patient's
medical condition requires accurate monitor-
ing of hemodynamics or determination of re-
peated blood gas analyses.
The invasive arterial transducer set is zeroed
at the level of the foramen of Monro. Central
venous line for central venous pressure (CVP)
measurements or right atrial catheter for pos-
sible air aspiration is not routinely inserted
before surgery, not even for patients in sitting
position. CVP, cardiac index and systemic vas-
cular resistance may be monitored by means
of arterial and central venous catheters (arte-
rial pressure-based cardiac output, Vigileo™
or Picco™) in patients on vasoactive agents or
needing extensive fluid administration at the
OR or ICU. Hourly urine output is measured in
all craniotomy patients.
Side-stream spirometry and airway gas pa-
rameters (inspired O2
, end-tidal CO2
and O2
,
end-tidal sevoflurane/isoflurane, and MAC) are
monitored after intubation. Ventilatory and
airway gas measurements are performed from
the breathing circuit at the connection piece
with a filter and flexible tube at 20 cm distance
to the tip of the intubation tube. The light dis-
posable breathing circuit minimizes the risk of
movement of the endotracheal tube during the
actual positioning of the patient for the sur-
gery. The cuff pressure of intubation tube is
measured continuously.
Core temperature is measured with a nasopha-
ryngeal temperature probe in all patients, and
peripheral temperature with a finger probe in
patients undergoing cerebrovascular bypass or
microvascular reconstructions. During anesthe-
sia blood gas analysis uncorrected for tempera-
ture is performed routinely to ensure optimal
PaCO2
and PaO2
. In some cases, ICP is measured
via ventriculostomy or intraparenchymal trans-
ducer before the dura is opened. In the sitting
or semi-sitting position the precordial doppler
ultrasonography probe is placed over the fifth
intercostal space, just to the right of the ster-
num, to detect possible venous air emboli in
the right atrium.
The neuromuscular blockade is monitored by a
neurostimulator (train of four or double burst
stimulation). The twitch response is evaluated
from the arm that is not affected by a possible
hemiparesis.

51
Preoperative assessment and induction of anesthesia | 3
3.3. PREOPERATIVE ASSESSMENT AND
INDUCTION OF ANESTHESIA
On most occasions, preoperative evaluation is
performed the day before the scheduled sur-
gery, but in complicated cases, the patient can
be invited to the hospital for a separate preop-
erative visit. In addition to clinical examination,
ECG and laboratory tests are obtained (Table
3-4). As a general rule, patient's health status
is optimized if the delay is not considered to
worsen the patient's neurosurgical outcome.
Elective patients with normal consciousness
are premedicated with oral diazepam, except
for certain special procedures (e.g. surgery for
epilepsy under neurophysiologic monitoring).
Small children are premedicated with mida-
zolam. Preoperatively, spontaneously breathing
patients are usually not given any opioids in
fear of respiratory depression and accumula-
tion of CO2
leading to an increase in ICP. Anti-
convulsants are not discontinued preoperative-
ly. However, in patients scheduled for epilepsy
surgery, the preoperative dosage or type of an-
ticonvulsants may be modified to enable intra-
operative localization of epileptic foci by corti-
cal EEG. Other prescribed drugs are considered
individually. The cessation of antithrombotic
drugs are discussed in section 3.7.4.
Before the induction of anesthesia we recom-
mend glycopyrrolate 0.2 mg intravenously. The
anesthesia for craniotomy is induced with in-
travenous fentanyl (5-7 µg/kg) and thiopental
(3-7 mg/kg). Thiopental is preferred to propo-
fol because of its verified antiepileptic prop-
erty. The dose of fentanyl (5-7 µg/kg) is suf-
ficient to prevent the hemodynamic response
to laryngoscopy and intubation without delay-
ing emerging from anesthesia. Orotracheal in-
tubation is used, unless the surgical approach
requires nasotracheal intubation. Supraglottic
airways, such as laryngeal mask, are not used.
The intubation tube is fixed firmly with tape
without compressing jugular veins.
Possible hypotension (estimated CPP < 60
mmHg) is corrected immediately by increments
of intravenous phenylephrine (0.025-0.1 mg)
or ephedrine (2.5-5 mg). After intubation, me-
chanical volume controlled ventilation without
any positive end-expiratory pressure (PEEP) is
adjusted according to the end-tidal CO2
to-
gether with hemodynamical profile. Later on,
gas exchange is confirmed by arterial blood gas
analysis. Volatile anesthetics are not adminis-
tered until mild hyperventilation is confirmed.
Coagulation profile
Normal  proceed normally
Abnormal  corrective steps
Consciousness
Normal  proceed normally
Decreased  no sedative premedication, plan
for delayed extubation at NICU
Neurological deficits
Lower cranial nerve dysfunction  warn patient
of prolonged ventilator therapy and
possible tracheostomy
Pre-op CT/MRI scans
Normal ICP  proceed normally
Signs of raised ICP  plan anesthesia accordingly
(mannitol, choice of anesthetics)
Planning of approach and positioning
I.v.-lines, arterial cannula in appropriate extremity
Easy access to airways
Possibility of major bleeding  have blood cross
checked
Special techniques will be employed (e.g. adenosine)
 prepare accordingly
Table 3-4. Preoperative assessment by the anesthesiologist

52
3 | Preoperative assessment and induction of anesthesia
Figure 3-5. (a-c) Nasal endotracheal intubation under local anesthesia and light sedation in a patient
with instability of cervical spine, performed by Dr. Juhani Haasio (published with patient‘s permission)
A B
C
Neuromuscular blockade is achieved with ro-
curonium. Succinylcholine is administered, un-
less contraindicated, to facilitate intubation
in patients requiring instant preparation for
neurophysiological monitoring (motor evoked
potential, MEP), or in selected cases of antici-
pated difficult airway. In patients with antici-
pated difficult intubation or instability in the
cervical spine, nasal endotracheal intubation
under local anesthesia and light sedation (fen-
tanyl 0.05-0.1 mg i.v., diazepam 2.5-5 mg i.v.)
is performed with fiberscope (Figure 3-5). Topi-
cal anesthesia of the nasal passage is achieved
with cotton sticks soaked in 4% lidocaine or
cocaine, and topical anesthesia of the pharynx,
larynx and trachea by injecting 4% lidocaine
either transtracheally or sprayed through the
working channel of the fiberscope.

53
Maintenance of anesthesia | 3
3.4. MAINTENANCE OF ANESTHESIA
The anesthesia method is selected according to
the CNS pathology and the effects of various
anesthetic agents on CBF and ICP (Table 3-2).
Patients can be roughly divided into two cat-
egories: (1) those without any signs of raised
ICP, scheduled for elective craniotomy, and (2)
those with known high ICP, any acute trauma,
or intracranial bleeding (Table 3-5). In selected
cases, special approaches are needed.
If there are no signs of brain swelling or elevat-
ed ICP, anesthesia is maintained with sevoflu-
rane or isoflurane in oxygen mixed with either
N2
O or air up to 1.0 MAC. In our practice, N2
O
is usually a component of inhalation anesthe-
sia. It allows lower inspired concentrations of
sevoflurane or isoflurane to achieve the ad-
equate depth of anesthesia (1.0 MAC). One
should remember, that the cerebral vasodila-
tory effect of N2
O is blunted by the simultane-
ous administration of intravenous barbiturates,
benzodiazepins or propofol. The poor solubility
of N2
O permits rapid recovery from anesthe-
sia. We continue to give N2
O until the end of
surgery. N2
O equilibrates with intracranial air
before the dura is closed. Thus, once the dura
is closed and N2
O discontinued, the amount of
intracranial air will decrease as N2
O diffuses
back into the bloodstream. The use of N2
O dur-
ing neurosurgery does not cause detrimental
long-term neurologic or neuropsychological
outcome. N2
O is contraindicated in patients
with increased risk of venous air embolism
(VAE), recraniotomy within a few weeks, severe
cardiovascular disease or excessive air in body
cavities (e.g. pneumothorax, intestinal occlu-
sion or perforation).
In patients with signs of high ICP, acute brain
injury, or tight brain during surgery, anesthesia
is maintained with propofol infusion (6-12 mg/
kg/hour) without any inhaled anesthetics. The
discontinuation of all inhaled anesthetics of-
ten promptly decreases brain swelling without
any further interventions. However, if the brain
continues to swell and threatens to herniate
through the dural opening, additional doses
of mannitol, hypertonic saline and thiopental
may be given. Momentary deep hyperventila-
tion (PaCO2
3.5 kPa) and head elevation can
also attenuate brain congestion.
For intraoperative analgesia, either fentanyl bo-
luses (0.1 mg) or remifentanil infusion (0.125-
0.25 µg/kg/min) is administered. Fentanyl is
generally preferred in patients who are likely
to need controlled ventilation postoperatively,
and remifentanil in those who will be extubated
immediately after surgery. The dose of opioids
is adjusted according to the pain stimuli during
craniotomy. Remifentanil effectively blocks the
hemodynamic response induced by pain and
can be given in 0.05 to 0.15 mg boluses prior
to anticipated painful stimuli to prevent hyper-
tension. Remifentanil bolus is recommended
before the application of the head holder pins.
We do not routinely inject local anesthetics at
the site of these pins except in awake patients.
The site of skin incision is infiltrated with a
mixture of ropivacaine and lidocaine combined
with adrenalin. The most painful phases of cra-
nial surgery are the approach through the soft
tissues as well as wound closure. The repetitive
small doses of fentanyl should be administered
cautiously since the same total amount of fen-
tanyl can cause markedly higher plasma con-
centrations given as small boluses compared
to a greater single dose. In cases of sudden
profound changes in blood pressure or heart
rate, the neurosurgeon must be immediately
notified, since surgical manipulation of certain
brain areas may induce hemodynamical distur-
bances. Neuromuscular blockade is maintained
with boluses of rocuronium as needed.

54
3 | Maintenance of anesthesia
Table 3-5. Anesthesia in Helsinki Neurosurgical OR
Preoperative medication
• Diazepam 5–15 mg orally if normal consciousness
• In children (>1 year) diazepam or midazolam 0.3–0.5 mg/kg orally (max. 15 mg)
• Regular oral antiepileptic drugs
• Betamethasone (Betapred 4mg/ml) with proton pump inhibitor in CNS tumor patients
• Hydrocortison with proton pump inhibitor in pituitary tumors
• Regular antihypertensive (excluding ACE-inhibitors, diuretics), asthma and COPD drugs and statins
• Insulin i.v., as needed, in diabetic patients, B-gluc aim 5–8 mmol/l
Induction
• One peripheral i.v. cannula before induction, another 17-gauge i.v. cannula in antecubital vein
after induction
• Glycopyrrolate 0.2 mg or 5 μg/kg (in children) i.v.
• Fentanyl 5–7 μg/kg. i.v.
• Thiopental 3–7 mg/kg i.v.
• Rocuronium 0.6–1.0 mg/kg i.v. or succinylcholine 1.0–1.5 mg/kg i.v.
• Vancomycin 1 g (or 20 mg/kg) i.v. in 250 ml of normal saline in CNS surgery, otherwise
cefuroxime 1.5 g i.v.
• 15% mannitol 500 ml (or 1g/kg) as indicated
Pulmonary/airway management
• Oral endotracheal intubation
• Nasal fiberoptic endotracheal intubation under local anesthesia if anticipated difficult airway or
instability in cervical spine
• Firm fixation of intubation tube by tape without jugular vein compression
• Access to endotracheal tube in every patient position
• FiO2
0.4–1.0 (in sitting position and during temporary clipping 1.0). SaO2
>95%, PaO2
>13 kPa
• Normoventilation PaCO2
4.5–5.0 kPa with volume controlled ventilator, TV 7-10 ml/kg, respiration
rate 10–15/min, no routine PEEP
• Mild hyperventilation (PaCO2
4.0–4.5 kPa) in primary surgery of TBI as needed and to counteract the
vasodilatory effects of inhaled anesthetics
Maintenance of anesthesia
Normal ICP, uncomplicated surgery
• Sevoflurane (or isoflurane) in O2
/N2
O up to 1 MAC
• Fentanyl boluses (0.1 mg) or remifentanil infusion (0.125–0.25 μg/kg/min)
• Rocuronium as needed
High ICP, tight brain, emergency surgery
• Propofol-infusion (6–12 mg/kg/hour)
• Remifentanil infusion (0.125–0.25 μg/kg/min) or fentanyl boluses (0.1 mg)
• Rocuronium as needed
• No inhaled anesthetics
Termination of anesthesia
• Postoperative controlled ventilation and sedation is discussed in each case separately
• Normoventilation until removal of endotracheal tube, avoid hypertension
• Patient has to be awake, obey commands, breathe adequately and have core temperature above
35.0–35.5 °C before extubation.
ACE, angiotensin-converting enzyme; CNS, central nervous system; COPD, chronic obstructive pulmonary disease; FiO2
,
inspired oxygen concentration; TV, tidal volume; MAC, minimum alveolar concentration; TBI, traumatic brain injury;
PEEP, positive end-expiratory pressure; i.v., intravenous.

55
Termination of anesthesia | 3
3.5. TERMINATION OF ANESTHESIA
The need for postoperative controlled ventila-
tion and sedation is evaluated on an individual
basis. After infratentorial or central supratento-
rial (sellar-parasellar) surgery the patients are
usually mechanically ventilated and kept se-
dated with propofol 2-4 hours postoperatively.
After a control computer tomography (CT) scan
they are allowed to awake slowly at the ICU.
The function of cranial nerves is also assessed
clinically before removal of the endotracheal
tube if dysphagia is suspected. When a laryn-
go-pharyngeal dysfunction is verified (cranial
nerves IX-X), the patient is promptly tracheos-
tomized, as extubation would bear a risk for
aspiration of gastric contents.
Before anticipated extubation, the end-tidal
concentration of CO2
should not be allowed
to rise. In case of a postoperative intracranial
hematoma, even mild hypercapnia can cause a
marked increase in the ICP. The endotracheal
tube is not removed until the patient is awake,
obeys commands, breathes adequately and core
temperature is above 35.0-35.5 °C. Before ter-
mination of anesthesia, recovery of neuromus-
cular function is also verified by neurostimula-
tor (train of four or double burst stimulation).
If the awakening time is prolonged beyond the
expected elimination time of the effects of the
anesthetic agents, a CT scan should be consid-
ered to rule out postoperative hematoma or
other causes of unconsciousness. In neurosur-
gical patients, awakening can be slow after the
excision of large tumors.
After discontinuation of the anesthetic agents,
including the infusion of remifentanil, the in-
crease (or decrease) in arterial blood pressure
must be controlled. Boluses of labetalol (10-20
mg i.v.) instantly decrease the blood pressure.
Alternatively, intravenous clonidine (150 µg as
infusion) may be administered 30 min before
extubation in hypertensive patients. Any sud-
den increases in arterial blood pressure carry
a risk for intracranial bleeding or brain edema.
This is especially true for AVM patients, who
may be kept in mild hypotension for several
days after surgery. In contrast, in SAH patients,
normo- or mild hypertension is often desired
once the aneurysm has been secured. The in-
crease in blood pressure is achieved with phe-
nylephrine infusion and/or intravenous fluid
deficit correction by Ringer's acetate or rapidly
degradable hydroxyethylstarch (tetrastarch).
If remifentanil alone has been used to provide
the intraoperative analgesia and a relatively
long period of time has elapsed (> 2-4 hours)
after the induction dose of fentanyl (5-7 µg/
kg) without additional doses, an opioid (fenta-
nyl 0.05-0.1 mg or oxycodone 2-4 mg intrave-
nously) with or without intravenous paraceta-
mol is given approximately 15 to 30 minutes
before planned extubation. Without this addi-
tional pain medication, the risk of uncontrolled
postoperative pain, hypertension and postpera-
tive bleeding increases.

56
3 | Fluid management and blood transfusions
3.6. FLUID MANAGEMENT AND
BLOOD TRANSFUSIONS
The objective of fluid therapy in neurosurgery is
to keep the patient normovolemic. In general,
neurosurgical patients should not be run dry
as previously suggested. In Helsinki, Ringer's
acetate (with or without additional sodium
chloride) is the intravenous fluid covering the
basal fluid requirements. The additional volume
deficits are replaced by combination of Ringer's
acetate (with or without additional sodium),
hypo- or hypertonic saline, 6% tetrastarch in
normal saline (hydroxyethylstarch, molecular
weight 130 kDa, molar substitution ration 0.4),
4% albumin or blood products (fresh frozen
plasma, red blood cell or platelet concentrates).
Intravenous fluids containing glucose are ad-
ministered only in hypoglycemic patients or
with insulin in patients having type I diabetes.
Water movement across the blood brain bar-
rier depends on the osmotic gradient between
plasma and the brain. The plasma Na+
concen-
tration correlates well with the osmotic pres-
sure of the plasma and is a relatively accurate
measure of the total body osmolality. It must
be emphasized that a decrease in plasma os-
molality by 1 mOsm/kg H2
O may increase in-
tracranial water content by 5 ml resulting in
an ICP increase of 10 mmHg, assuming that
normal brain compliance is approximately 0.5
ml/mmHg.
Ringer's acetate (Na 130, Cl 112 mmol/l) is
slightly hypotonic in relation to plasma and the
infusion of large amounts (>2000-3000 ml) may
increase brain water content. Therefore we add
20-40 mmol of NaCl in 1000 ml of Ringer's ac-
etate to make it isotonic or slightly hypertonic.
Correspondingly, the current colloid solutions,
i.e. tetrastarch or 4% albumin, have both normal
saline (NaCl 154 mmol/l) as a carrier solution,
which is preferable in neurosurgical patients.
The reason why we do not observe metabolic
hyperchloremic acidosis related to NaCl admin-
istration in the OR or ICU may be the acetate in
Ringer's solution. Acetate is metabolized to bi-
carbonate in almost all tissues, which may keep
the acid-base equilibrium normal.
The basal infusion rate of Ringer's acetate in
adults is approximately 80-100 ml/hour. In
children we administer fluid according to the
Holliday-Segar formula. During neurosurgery
the volume deficit by preoperative dehydra-
tion, increased body temperature, mannitol
promoted urine output, or blood loss is re-
placed individually. In children during crani-
otomy, we start Ringer's acetate 10 ml/kg for
the first hour and then continue with 5 ml/
kg/hour. Postoperatively, 75% of normal fluid
requirement is administered. Colloid solutions
are given to replace plasma losses or whenever
there is indication to improve circulation in
hypovolemia. ICP reduction therapy includes
15% mannitol (500 ml or 0.25-1.0 g/kg) with
or without furosemide or alternatively 100 ml
of 7.6 % saline (if P-Na < 150 mmol/l). At the
end of surgery special attention is paid to post-
operative fluid balance. In the OR, the anesthe-
siologist also plan the primary treatment of
patients having increased risk of cerebral salt
wasting syndrome (increased risk for hypovo-
lemia), syndrome of inappropriate secretion of
antidiuretic hormone (SIADH) (fluid restriction)
or diabetes insipidus (increased risk of hypovo-
lemia and hyperosmolality).
Hematocrit below the level of 0.30-0.35 is the
trigger for red blood cell transfusion to guar-
antee oxygen delivery. CBF and ICP are also
increased during hemodilution. Coagulation
capacity is impaired if hematocrit drops below
0.30. On the other hand, if it rises above 0.55 it
reduces CBF due to increase in blood viscosity.
In our practice, the target INR (International
Normalized Ratio) is <1.5 or P-TT% > 60%
(plasma partial thromboplastin time value, nor-
mal 70-130%) and platelet count >100x109/l
in patients undergoing CNS surgery.

57
Supine position | Anesthesiological considerations for patient positioning | 3
3.7. ANESTHESIOLOGICAL CONSIDERATIONS
FOR PATIENT POSITIONING
The neurosurgical principles of patient position-
ing in Helsinki are presented in section 4.4.2.
and each positioning for different approaches
are described in further detail in Chapter 5. The
neurosurgeon and the anesthesiologist have to
work closely together to optimize the surgi-
cal access without compromising the patient's
medical condition due to improper positioning.
The anesthesiologist is responsible for ensuring
patient's oxygenation, ventilation and CPP dur-
ing and after positioning, despite the possible
short interruptions of monitoring. The anesthe-
siologist must personally supervise the correct
placement of the endotracheal tube and the
breathing circuit connected to the ventilator
during patient positioning. The possibility of
accidental compression of the airway during
positioning or the actual surgery must be kept
in mind. Therefore in our practice, the ventila-
tor and anesthesia team are placed on the left
side of the patient, or with the lateral position,
on the side the patient is facing. This optimizes
free access to the patient's airway as needed.
The intravenous and arterial catheters should
be securely attached. The intravenous lines for
anesthetic and vasoactive agents must be vis-
ible and easily available during anesthesia in
all positions. Special care must also be taken
to prevent excessive rotation or tilting of the
neck and to avoid any peripheral nerve injury
in these situations.
3.7.1. Supine position
The head is elevated approximately 20 cm
above the level of the heart in all positions
(Figure 3-6). The anesthesia is induced in su-
pine position, which is per se not related to
serious cardiovascular adverse effects. The
risk of movement of endotracheal tube is also
minimal. In the supine position the functional
residual capacity of lungs may be preserved by
slight elevation of the upper body. The arms are
placed beside the body.
Fig 3-6. Supine position

58
Figure 3-7. Prone position from the side (a) and from the cranial end (b) of the table.
(c) Gel cushions are used to support the patient
A
B C
3.7.2. Prone, lateral park bench and
kneeling positions
Adequate depth of anesthesia and neuromus-
cular blockade is provided before positioning
starts. Otherwise, the patients with endotra-
cheal tube may start coughing.
In contrast to supine position, cardiac out-
put has been reported to decrease 17-24% in
prone position, similarly as in sitting position
(Figure 3-7). However, the decrease in cardiac
output in prone position is not always associ-
ated with hypotension. Significant deteriora-
tion of cardiac output or hypotension has also
been observed in the lateral position. Therefore,
it is mandatory to adjust arterial transducer set
at the level of foramen Monro to observe any
hypotension simultaneously as the patient’s
position is changed. If any hemodynamical dif-
ficulties arise, intravenous vasoactive agents
are readily available to optimise CPP.
The lateral park bench (Figure 3-8) or prone
position may decrease pulmonary function.
However, in the lateral position the functional
residual capacity may also increase in the non-
dependent lung and compensate the effects of
atelectasis formation in the dependent lung. In
3 | Anesthesiological considerations for patient positioning | Prone and lateral park bench position

59
Park bench position | Anesthesiological considerations for patient positioning | 3
Figure 3-8. Lateral park bench position from the side facing the anesthesiologist (a) providing unobstructed
access to the patient‘s airways, and from the cranial end (b) of the table
A
B

60
3 | Anesthesiological considerations for patient positioning | Kneeling position
Figure 3-9. (a) Kneeling position (b) Head holder with mirror
B
A
C
Figure 3-10. (c) Legrest supports the patient if the bed
needs to be tilted forward

61
Sitting position | Anesthesiological considerations for patient positioning | 3
Figure 3-10. (a) Sitting position for infratentorial supracerebellar and fourth ventricle approaches.
(b) G-suit trousers.
A
B

3 | Anesthesiological considerations for patient positioning | Sitting position
addition, prone position has also been shown
to increase functional residual capacity of the
lungs.
Thoracic or lumbar spinal surgery is usually
performed in prone (Figure 3-7) or kneeling
position (Figure 3-9a). The head is placed on
a head holder with a mirror enabling visualisa-
tion of eyes and endotracheal tube during an-
esthesia (Figure 3-9b). The rolls are employed
to allow the chest and abdomen to move freely.
Furthermore, careful placement of patient in
prone position aims to avoid forehead or orbital
compression (may result in retinal ischemia and
blindness), and compression of axillae, breasts,
iliac crests, groin vessels, penis and knees.
3.7.3. Sitting position
In Helsinki Neurosurgical Department, sitting
position has been used in selected cases of
posterior fossa surgery since the 1930's, and
all vestibular schwannomas were operated on
in an upright position since the early 1960's
to the end of 1980's. Nowadays, lateral park
bench position is used for these lesions. The
current sitting position for infratentorial su-
pracerebellar and midline fourth ventricle ap-
proaches is shown in Figure 3-10.
The general contraindications for the sitting
position are severe congestive cardiac failure,
uncontrolled hypertension, cerebral ischemia
when upright and awake, extremes of age <
6 months or > 80 years, ventriculoatrial shunt,
known open foramen ovale or right atrial pres-
sure in excess of left atrial pressure.
Before the positioning starts, all the adult pa-
tients are fitted with G-suit trousers inflated
with compressed air to the pressure of about
40 mmHg to decrease venous pooling in the
lower extremities. In children, the same is
achieved with elastic bandages wrapped
around the calfs and thighs. A bolus of intra-
venous Ringer's acetate or tetrastarch (colloid
solution) is administered at the discretion of
the anesthesiologist in charge. Mayfield head
frame is attached to patient's head while still
in the supine position.
In adults, the target MAP - measured at the
level of foramen Monro - is 60 mmHg or high-
er, and/or systolic arterial pressure 100 mmHg
or higher. The precordial Doppler ultrasonog-
raphy probe is placed over the fifth intercos-
tal space, just to the right of the sternum, to
detect possible venous air embolism. The pa-
tients are normoventilated (target PaCO2
= 4.4
– 5.0 kPa) with 100% inspired oxygen without
positive end-expiratory pressure, by volume
controlled ventilation. N2
O is not given. Arte-
rial blood gases are analyzed after the induc-
tion of anesthesia and thereafter as clinically
needed. Upon suspicion of venous air embo-
lism (a specific sound in the precordial Doppler,
sudden drop in the ETCO2
of >0.3 kPa (≈ 0.3
%)) without prior change in the ventilation or
concomitant decrease in the arterial pressure,
the neurosurgeon is immediately informed. In
some cases, the jugular veins are gently com-
pressed manually, to help the neurosurgeon to
identify the site of air entry. The neurosurgeon
closes the leak by first covering the site with
compresses soaked in normal saline and then
either applies wax into the bone sinuses or co-
agulates open veins with bipolar. We do not at-
tempt to aspirate air from the right atrium. The
operating table is tilted only on the occasion of
hemodynamic collapse.
62

63
Postoperative care in the ICU | 3
3.8. POSTOPERATIVE CARE IN THE ICU
One of the most important issues in the post-
operative care of the neurosurgical patients is
that information about the course of surgery
and anesthesia is available to the ICU person
nel when the patient arrives there. The neuro-
surgeon fills in a form before leaving the OR,
stating the preoperative neurological condition
and the expected postoperative findings (e.g.
dilated pupil because of oculomotor nerve ma-
nipulation, or possible hemiparesis). This may
help to avoid unnecessary radiological investi-
gations. Any special requirements (exception-
ally low or high blood pressure, early CT con-
trols etc.) should also be made clear.
After uneventful craniotomy (unruptured an-
eurysm, small supratentorial tumors) the min-
imum length of stay in ICU is six hours, but
preferably, and always in more complex cases,
overnight surveillance is the norm. Glasgow
Coma Score, pupillary size and reaction to
light, and muscle strength are checked and re-
corded hourly.
Postoperative control of hemodynamics is of ut-
most importance in the ICU. Perioperative sys-
temic hypertension and coagulation disorders
are associated with postoperative hemorrhage.
Routinely, the systolic arterial pressure is kept
under 160 mmHg postoperatively. Large men-
ingiomas and AVMs are exceptionally prone to
postoperative bleeding, and these patients are
often kept sedated and relatively hypotensive
for 3-4 hours or until the next morning. They
are woken up only after postoperative CT, CTA
and/or DSA imaging is found acceptable. Even
then utmost care is taken to avoid sudden in-
creases in blood pressure during emergence
from sedation and extubation (Tables 3-6 and
3-7). Some of the common practices used in
different types of surgical procedures are sum-
marized in Table 3-8.
Nausea and pain are common after neurosur-
gical preocedures, but the medications used
should not be overly sedative or interfere with
blood coagulation. For pain relief oxycodone
(an opioid closely resembling morphine in dos-
age and effects) is given in small (2-3 mg i.v.)
increments to avoid respiratory depression and
excess sedation. At the ordinary ward intra-
muscular or oral oxycodone is given as needed.
Paracetamol (acetaminophen) is also adminis-
tered (initially intravenously, later orally). Non-
steroidal anti-inflammatory drugs (NSAID's)
are not given on the first postoperative day
because of their inhibitory effect on platelet
aggregation. Rarely, in patients without car-
diovascular disease or no history of vascular
surgery, parecoxib (COX-2 inhibitor) 40 mg
i.v. may be given as a single dose. Nausea and
vomiting are treated with 5-HT3
-receptor an-
tagonists (granisetron 1 mg i.v.) or small doses
of droperidol (0.5 mg i.v.).
Table 3-6. Hemodynamic control during
extubation in NICU
• Clonidine 150 µg/NaCl 0.9% 100 ml 30 min
infusion (or dexmedetomidine-infusion)
• Stop sedation (usually propofol-infusion)
• Labetalol 10–20 mg and/or hydralazine
6.25 mg i.v. increments as needed
• Extubation when patient obeys simple
commands
Table 3-7. Indications for postoperative
sedation and controlled ventilation
• Pre-op unconscious or decreased level of
consciousness
• Long duration of temporary clipping
• Expected lower cranial nerve dysfunction
or palsy
• Easily bleeding operative field
• Large AVM: blood pressure control
• Brain swelling

64
Table 3-8. Common practices at Helsinki NICU
Supratentorial surgery (tumors, unruptured aneurysms)
• Early awakening and extubation in OR
• Systolic arterial pressure <160 mmHg
• In selected cases (large tumors, complex aneurysms): post-op sedation and tight hemodynamic control
(usually systolic arterial pressure 120–130 mmHg for 3–4 hours), control CT and delayed extubation
Infratentorial surgery
Small tumors in “benign” locations or microvascular decompression of trigeminal nerve
• Early awakening and extubation in OR
• Systolic arterial pressure <160 mmHg
Large tumors or tumors in delicate location (pons, medulla, close to IX-XI nerves)
• Post-op sedation and tight hemodynamic control (usually systolic arterial pressure 120–130 mmHg
for 2–4 hours), control CT and delayed extubation
• Pharyngeal function always checked with extubation  tracheostomy in case of IX-XI cranial nerve
dysfunction
AVMs
Small AVMs
• Early awakening and extubation in OR, normotension (systolic arterial pressure <160 mmHg)
Medium sized AVMs or problems with hemostasis during surgery
• Sedation until control CT + CTA/DSA
• Tight hemodynamic control (usually systolic arterial pressure <120–130 mmHg)
Large AVMs
• Sedation until control CT + CTA/DSA
• Extremely tight hemodynamic control (systolic arterial pressure 90–110 mmHg)
• Slow emergence and extubation (see Table 3-6)
• Systolic arterial pressure target allowed to rise by 10 mmHg daily (up to <150 mmHg),
antihypertensive medication for 1–2 weeks post-op
• Fluid restriction to minimize cerebral edema
Ruptured aneurysms
• Early awakening and extubation in OR only in H&H 1–2 patients with uneventful surgery
H&H 1–2; Fisher 1–2
• Systolic arterial pressure >120 mmHg
• Normovolemia, Ringer 2500–3000 ml/day
• Nimodipine 60 mg x 6 p.o.
• Systolic arterial pressure >140 mmHg
• Normovolemia, CVP 5–10 mmHg, Ringer 3000–4000 ml/day
• Systolic arterial pressure >150–160 mmHg
• Slight hypervolemia, CVP 6–12 mmHg, Ringer 3000-4000 ml/day + colloid 500–1000 ml/day
Bypass surgery
• Early awakening and extubation in OR if the length of operation <3–4 h
• Normotension, systolic arterial pressure 120–160 mmHg
• Avoid vasoconstriction, liberal fluid therapy
• Antiplatelet therapy with acetylsalicylic acid (300 mg i.v. or 100 mg p.o.) in most cases
CVP, central venous pressure; H&H, Hunt and Hess grading scale; i.v., intravenous; p.o., peroral.
3 | Postoperative care in the ICU

65
Special situations | 3
According to our follow-up during the years
2009-2010, pain scores (scale 0-10) after su-
pratentorial craniotomy are low (median 2-3).
However, the need for postoperative analgesia
may differ depending on the type of surgery
and pathology. Also depression and disease-
related confusion may obscure the actual need
for analgesia. Postoperative pain is treated by
intravenous patient-controlled analgesia (PCA)
with oxycodone in patients undergoing major
spinal surgery. Postcraniotomy pain is seldom
treated by PCA in our clinic.
3.9. SPECIAL SITUATIONS
3.9.1. Temporary clipping in aneurysm surgery
Depending on the duration of the temporary
occlusion of a cerebral artery, protective meas-
ures are needed. When the expected duration
is less than 60 to 120 seconds, there is no need
for interventions, but if the duration is likely to
be longer, the following interventions are made
before the placement of a temporary clip:
(a) The inspiratory concentration of oxygen is
increased to 100%.
(b) Barbiturate (thiopental) is administered as
an intravenous bolus (3-5 mg/kg) to reduce
brain metabolism and oxygen consump-
tion. A second, smaller dose of thiopental,
may be administered prior to reocclusion
of the same artery, if reperfusion is pro-
vided before that.
(c) Phenylephrine in 0.025 to 0.1 mg incre-
ments is given in case of hypotension.
(d) Additional doses of phenylephrine may be
given to increase the arterial blood pres-
sure at least 20% above baseline to ensure
retrograde circulation to the areas distal to
the temporary clip, if a temporary occlusion
exceeding 5-10 min is planned. Sometimes
this may induce cumbersome bleeding at
the operative area, prolonging and making
the temporary clip adjustment and removal
even more difficult.
Postoperative controlled ventilation and seda-
tion are often considered necessary when the
duration of temporary clipping exceeds 5 to 10
minutes.

66
3 | Special situations
3.9.2. Adenosine and short cardiac arrest
In the literature, there are many descriptions
of the use of adenosine to induce circulatory
arrest during cardiac and brain surgery. Ad-
enosine is an antiarrhythmic drug that effects
the sinoatrial conduction, and is normally used
for treatment of tachyarrhythmias. We have
used a short cardiac arrest or significant drop
in blood pressure induced by adenosine either
to control bleeding from a ruptured aneurysm
or in complex unruptured aneurysms to allow
proper clip placement. To induce cardiac arrest,
0.4 mg/kg of adenosine, followed by 10 ml of
normal saline, is injected as a rapid bolus in an
antecubital vein. This induces an approximately
10-second arrest. During this short period, the
operative field is cleared by suction, and a tem-
porary clip(s) or a so-called pilot clip is applied
in place. Normal cardiac rhythm returns usu-
ally without any need for medical intervention.
If adenosine use is anticipated preoperatively,
cardiac pads are placed on the chest of the pa-
tient in case of need for cardioversion or cardi-
ac pacing. Cardioversion or temporary cardiac
pacing has not been needed so far to treat a
tachyarrhythmia or bradyarrhythmia. In more
than 40 cases in which we have used adenos-
ine intraoperatively, there have been no signif-
icant adverse reactions (arrhythmia, arrest or
long-lasting hypotension) associated with its
use. The cardiovascular effects of adenosine are
usually completely worn off in less than one
minute. If clinically indicated, the bolus dose of
adenosine may be administered repeatedly.
3.9.3. Intraoperative neurophysiologic
monitoring
The choice of anesthetic agents depends on the
mode of neurophysiologic monitoring. Anesthet-
ic agents may prolong the latencies of evoked
potentials and also decrease the amplitudes
in a drug-specific manner, inhaled anesthet-
ics causing more interference than intravenous
anesthetics. Importantly, whatever anesthetic
combination is chosen, the depth of anesthesia
should be kept stable. Hypothermia suppresses
evoked potentials, thus core temperature is con-
tinuously monitored, and normothermia is main-
tained with external warming. Of the evoked
potentials, brainstem auditory evoked potentials
(BAEP) are rather resistant to anesthesia, but
when cortical evoked potentials are measured,
intravenous anesthesia with propofol and fen-
tanyl (or remifentanil) is preferred (Table 3-9).
Dexmedetomidine, an alfa-2-adrenoceptor ago-
nist, is a feasible choice in patients when neither
propofol nor inhaled anesthetics are allowed. In
cases with motor evoked potential (MEP) moni-
toring or direct cortical stimulation, muscle re-
laxants are not given.
Anesthetic agents have characteristic effects on
the EEG. To ensure intraoperative corticography
of satisfactory quality during epilepsy surgery,
anesthesia is maintained either with isoflurane
or propofol, which are discontinued well before
monitoring periods. Propofol may be inferior to
isoflurane, because of the reported induction
of generalized electrical activity. During the
monitoring periods, anesthesia is maintained
with dexmedetomidine and remifentanil or
fentanyl. In individual cases, droperidol may be
given to deepen the anesthesia.

67
Special situations | 3
Table 3-9. Anesthesia during neurophysiologic monitoring
Measurement Anesthetic agents
BAEP propofol + opioid (fentanyl or remifentanil)
SEP propofol + opioid (fentanyl or remifentanil) + dexmedetomidine + muscle relaxant
MEP same as SEP but no muscle relaxant
Corticography opiod (fentanyl or remifentanil) + dexmedetomidine
BAEP, brainstem auditory evoked potentials; SEP, sensory evoked potentials; MEP, motor evoked potentials.
3.9.4. Antithrombotic drugs and
thromboembolism
The patients scheduled for neurosurgery in Hel-
sinki have a 5-day cessation of all antithrom-
boticdrugstoallowspontaneousrecoveryofthe
coagulation capacity with certain exceptions
(see below). Modified low molecular weight
heparin (LMWH) (enoxaparin) bridging therapy
is started as compensatory thromboprophy-
laxis preoperatively, and continued postopera-
tively, in patients with high risk for thrombosis,
such as mechanical mitral or tricuspidal valve,
atrial fibrillation with thromboembolism, his-
tory of deep venous thrombosis, thrombofilia
or coronary artery stent. In emergency cases,
the effects of anticoagulants or platelet inhibi-
tors are counteracted by specific antidotes or
transfusion of fresh frozen plasma or platelet
concentrates.
The normal (<1.5) INR is achieved usually in
four days after cessation of warfarin. Pro-
thrombin complex concentrate is administered
when the effect of warfarin has to be reversed
without delay. The dosage regimen is based on
INR values before and after the administration
of prothrombin complex concentrate. Vitamin
K (2-5 mg orally or i.v.) is administered simul-
taneously. Importantly, it may be indicated to
administer the dose of prothrombin complex
concentrate repeatedly to guarantee postop-
erative hemostasis since the half-life of coagu-
lation factor VII is 4-6 hours.
The effect of low dose acetylsalicylic acid and
clopidogrel on platelets lasts up to 7 days.
However, adequate platelet function for neu-
rosurgery may be achieved in 2-4 days after
the interruption of low dose acetylsalicylic
acid or clopidogrel. The elimination of low dose
acetylsalicylic acid or clopidogrel from plasma
takes 1-2 days, and new platelets are produced
approximately 50 x109/l/day, which might be
sufficient for normal hemostasis during neu-
rosurgery. In patients with recent coronary ar-
tery stenting, myocardial infarction, unstable
angina pectoris or in cerebral bypass surgery,
craniotomy is performed without interruption
of acetylsalicylic acid. However, if clopidogrel
is combined with acetylsalicylic acid, clopidog-
rel is interrupted 5 days before craniotomy.
All craniotomy patients have compression
stockings for prophylaxis of venous throm-
boembolism. In selected high-risk patients
and in patients on LMWH bridging therapy, a
mechanical arteriovenous pulsation device for
feet is applied and a low dose of enoxaparin
(20 mg once or twice daily s.c.) is administered
not earlier than 24 hours after craniotomy or
CNS surgery if there are no signs of bleeding
on control CT scan.

68
4 | Neurosurgeon´s position and movement

69
General Philosophy | 4
4.1. GENERAL PHILOSOPHY
The style of a surgeon is the image of his or
her mind. When you travel and see different
surgeons at work, you notice that there are
many different styles of microneurosurgery.
These styles and habits have been formed by
influences by mentors & trainers, their area
of interest (e.g. bypass, skull base) as well as
their individual character. Some sit, while oth-
ers stand. Some are faster and some are slower,
some take a break while others do not, some
like music in the OR and some prefer silence.
Some use bipolar dissection and others prefer
using microdissectors. And all have their rea-
sons for what they do: training, experience,
and resources of both the department and the
society. As long as the results are good and ex-
cellent, that is what matters. Sometimes there
is no wrong or right way. Just your way and
my way!
What matters is how the operation is develop-
ing, progressing, and the final outcome. Here
are a few brief points about the techniques of
Helsinki way of microneurosurgery. This style
of surgery, the pace, the results and the team is
the reason why so many come to see, and they
see so much in a short space of time. Because
of the fluency of technique the operations are
interesting and at a pace that can be easily fol-
lowed. The fellows that have the opportunity to
edit the operative videos know that to edit the
operations is difficult. Because there is very lit-
tle to edit out as there is little time of non-
action!
One of the key factors in Helsinki neurosurgery
is planning and mental image of the task ahead.
Each movement is pre-calculated, there is very
little time spent wondering what to do next. A
great part of the operation has been planned
already prior to the incision, and there is no
lethargy in the approach. The actual physical
surgery is often the second or third attempt,
since through mental preparation the neuro-
surgeon had performed the operation in his or
her mind already once or twice before stepping
into the OR. The other important factor is that
every movement and task is aimed to fulfill the
actual goal of the surgery. This means avoid-
ance of large and time consuming approaches
and techniques when the same result can be
obtained with less hazard using a smaller ap-
proach. Every step during surgery is simplified
as much as possible. It is go-go surgery! There
is much work to be done and there is no time
for long and laborious approaches when there
is an easier and faster way to achieve the same
result. Each procedure is divided into several
steps or phases, each of which should be com-
pleted before moving forward. In this way one
is prepared even for unexpected situations and
maintains control over the task ahead. The
general philosophy of Helsinki microneurosur-
gery can be simplified into: "simple, clean, fast,
and preserving normal anatomy."
4. PRINCIPLES OF HELSINKI MICRONEUROSURGERY

70
4 | Principles of microneurosurgery
4.2. PRINCIPLES OF MICRONEUROSURGERY
Since the advent of true microneurosurgi-
cal techniques introduced by Prof. Yaşargil,
there have been many techniques, instruments
and technological advances introduced into
this field. The introduction and application of
microsurgery in neurosurgery was a result of
long and hard development of the basic tech-
niques by Prof. Yaşargil in the laboratory of
Prof. Donaghy in Vermont, USA between 1965-
1966. These techniques were later developed
further, refined and consolidated over the next
25-year period in Zürich.
Microneurosurgery is not macroneurosurgery
using a microscope. Rather, it is a combination
of a special armamentarium consisting of the
microscope, the microsurgical tools, and the
choice and command of microsurgical tech-
niques. The choice and command of technique
can only be mastered with continuous practice.
This exercise should include both laboratory
training as well as the work in the operating
room. It will enhance the use of senses such as
depth perception, sensory feedback and even
sense of joint position, all of which are neces-
sary for microneurosurgery.
The use of high magnification, powerful light
source and stereoscopic vision allows the neu-
rosurgeon to use suitable delicate tools to op-
erate on central nervous system lesions in an
almost bloodless field as atraumatically as pos-
sible. The microscope allows visualization and
3D appreciation of the relevant and detailed
neuroanatomical structures. But to achieve
the optimal visualization of each structure, de-
tailed knowledge of the microanatomy, careful
preparation and execution of a given approach
is necessary. There are many small details,
some of them trivial, which affect the outcome
of a particular surgery. Here we try to summa-
rize what we have learned over the past years
about microneurosurgery and the instrumenta-
tion we find useful.

71
4.3. OPERATING ROOM SETUP
4.3.1. Technical setup
There should be always a consistency where
possible regarding the setup in the OR (Figure
4-1). All OR personnel should have optimal
access to the patient and all the equipment
they require. There are two main issues which
have to be taken into consideration: (1) the
surgeon's optimal position with respect to the
operation field, so as to allow relaxed posture
and optimal visualization of all the necessary
structures; and (2) the anesthesiologist's good
access to the patient's airways and all the nec-
essary i.v. routes. In addition several other key
factors need to be considered:
• Anticipation for the amount of room needed
for the surgeon to move.
• Position and flexibility of the microscope.
• Unhampered access between the scrub nurse
and surgeon to allow seamless exchange of
instruments. In case of a right-handed sur-
geon the majority of instruments are passed
to the right hand.
• Provision of room and access to the micro-
scope for any required assistants.
• Sufficient room and access for anesthesia,
and easy communication when necessary
regarding e.g. change of table height and etc.
Generally an attitude of utmost respect and
consideration for all the OR staff and team is
the Helsinki way, the team spirit of Helsinki.
Operating room setup | 4
Figure 4-1. The general setup of OR 1, Prof. Hernesniemi’s OR, in Töölö Hospital

72
4.3.2. Displays
Microneurosurgery is a team effort. This means
that all the personnel inside the OR need to be
aware of what is happening in the operation
field. With modern microscopes equipped with
high quality video cameras this can be easily
achieved. Monitors showing real time micro-
surgery to the anesthesiologist, the operating
room nurses, and the technicians are essential
and enhance teamwork and co-ordination. The
progress of the operations, moments of crucial
dissection or intervention, and timing for use
of bipolar coagulation are essential reasons for
such audiovisual equipment. The most impor-
tant display is the one used by the scrub nurse.
For her to be able to anticipate the surgeon's
next step, she has to have an unobstructed and
direct view on the monitor, which is placed pref-
erably directly in front of her. A second monitor
for anesthesia is very useful as well. Additional
displays can be then placed for assistants and
visitors. Live or real-time teaching of a large
number of residents and visitors is made pos-
sible by video monitors. Recording facilities for
still photos and videos can be used for teaching
and lecturing purposes, as well as documenta-
tion. The emerging high definition (HD) and 3D
microscope cameras can provide even better
possibilities for "learning by watching".
Figure 4-2. Several displays in the OR pro-vide the whole
team to observe the surgical field as seen through the
microscope. (a) The scrub nurse‘s display. (b) The visitors‘
display
4 | Operating room setup

73
Positioning and head fixation | 4
4.4. POSITIONING AND HEAD FIXATION
4.4.1. Operating table
The operating table is selected according to
personal preferences and financial resources. It
should provide stable positioning, and it should
also be equipped with a quick and reliable
mechanism for the staff to make swift posi-
tional changes during surgery, according to the
operating surgeon's wishes. Modern, mobile ta-
bles allow adjustment of each segment of the
table separately using remote control that is
handled during surgery by the anesthesiologi-
cal nurse. Flat tables with very limited possibil-
ity to tilt or bend some parts of the table are
not well suited for modern microneurosurgery.
4.4.2. Patient positioning
During positioning, comfortable and practical
working positions should be agreed on by the
neurosurgeon and the scrub nurse, with maxi-
mal mobility for the operating neurosurgeon.
The following principles are of prime impor-
tance for comfortable conduct of surgery:
• For all craniotomies the head of the patient
should be elevated approximately 20 cm above
the level of the heart. This facilitates a clean
and bloodless field with good venous outflow.
• The head is positioned so as to have some
help from the gravity to facilitate the appro-
priate part of the brain to fall away, and in-
crease view and access.
• Venous outflow should not be compromised
by heavy tilting or turning of the head or by
any constrictions at the neck.
• A comfortable working angle – usually down-
ward and somewhat forward – should be
ensured by careful positioning of the patient's
head and body.
• The head and body of the patient should be
so secured as to allow safe tilting and rota-
tion of the table to change the angle of view
and surgical access.
• The protection of the eyes, nose, ears, skin,
extremities, vulnerable nerves and compres-
sion points are paramount. The eyes are rou-
tinely covered with chloramphenicol eye
ointment to protect the eyes and keep them
shut. Some patients may be allergic to this
antibiotic.
• The pressure areas are protected with pads
and cushions.
The positions of the patient include supine,
prone, semi-sitting, sitting, and lateral ("park
bench"). From the above principles, the ones on
(a) the use of gravity and (b) the comfortable
working angle, dictate the best position of the
head. The body is then positioned accordingly.
However, every case is unique, and we always
tailor the position according to the lesion and
the patient's body and condition. Specific posi-
tionings for the most important approaches are
discussed in detail in Chapter 5.

74
4 | Neurosurgeon´s position and movement
4.4.3 Neurosurgeon's position and movement
The working posture is standing or sitting. We
prefer the standing position because it allows
much better mobility around the craniotomy
site, use of all available exposure, and im-
mediate change of position, losing no time in
moving the chair or the operation table. Many
small things, when taken together, often save
invaluable OR time by tens of minutes, even
hours. The patient is perfectly still, but the neu-
rosurgeon adjusts his or her position almost
constantly, using the mouthpiece to focus and
move the operation microscope laterally and
vertically. Visual access to the entire operative
field may also require lifting or lowering the ta-
ble – this should be a swift routine during sur-
gery. The neurosurgeon may also adjust height
by 3 to 4 cm by high-heeled clogs (by wearing
them or not) – platforms are seldom necessary.
Sitting might be more comfortable but reduces
mobility. Sitting is preferable in certain in-
stances, for example, during bypass operations
when the operative area is very small and the
angle of vision does not have to be changed.
Standing position does not affect the stability
of the hands compared to the sitting position if
a proper armrest is used (Figure 4-3).
The advantages of standing to operate are:
• Allows greater range of movements for the
surgeon to maneuver and facilitate surgical
access, especially when using the mouthpiece
on the microscope. This can be even slightly
augmented by wearing or removing surgical
clogs to alter the surgeon's height (Figure 4-4).
• Changing and switching positions is faster.
• It is easier and more accommodating for the
assistant.
• Due to increased use of proprioception, the
surgeon is consequently more aware of his
position in relation to his surroundings.
The greatest disadvantage of standing to oper-
ate is that it can be more tiring if one is not in
a good physical condition (Figure 4-5).
Figure 4-4. High-heeled clogs may be worn and removed
as desired to fine-tune the surgeon‘s height
Figure 4-5. Standing position allows freedom of
movement – even acrobatics!

75
Neurosurgeon´s position and movement | 4
Figure 4-3. (a) Armrest with adjustable height and
ball-and-socket joint at the base. (b) Armrest with
sterile covering. (c, d) Properly adjusted armrest
allows the arms to rest at neutral and relaxed
position, while providing stability comparable to
sitting position
A B
C
D

76
4 | Head fixation
4.4.4. Head fixation
In Helsinki style microneurosurgery, head fixa-
tion is used in all cranial procedures as well as
in all posterior and lateral approaches to the
cervical spine. The Sugita head fixation device,
used in Helsinki since 1980's after Prof. Sugita's
visit in 1979, has a good skin and muscle re-
traction system. It includes also an attachment
system for brain retractors, which makes it the
preferred head fixation device in Helsinki. The
Mayfield-Kees 3-pin head frame with one more
joint is more flexible. We use the Mayfield-Kees
head fixation device in the sitting position and
rarely in park-bench position (only for Janetta
operation) when linear skin incisions are used.
The Sugita device is preferred when heavy re-
traction of the skin flap or retractors to sup-
port the brain are needed. We do not like any
instruments or retractors constantly fixed im-
mediately above the craniotomy, as they may
be accidentally displaced and cause serious in-
juries. Pin fixation sites of the frames, as well
as the arch and the counter arch of the Sugita
frame, should allow total access to the opera-
tive field and not prevent free movements of
the neurosurgeon's hands or instruments or the
operating microscope. Arterial and venous flow
in the neck should not be compromised by head
positioning, and we fix the endotracheal tube
by adhesives instead of a string/ribbon around
the neck. The head should not be turned too
much, the cervical spine flexed or extended to
an extreme in any direction, and the trachea
overstretched or twisted. In temporal, parietal,
and lateral occipital approaches, the park-bench
position helps to avoid compression of the jug-
ular veins. After head fixation, further adjust-
ments of the patient's position should be per-
formed en bloc by moving the operation table.

77
Necessary or useful tools | 4
4.5. NECESSARY OR USEFUL TOOLS
Every neurosurgical style has its own specific
demands. Here we list the most important tools,
some of which are necessary, some very useful
adjuncts of Helsinki style microneurosurgery.
4.5.1. Operating microscope
A highly mobile operating microscope is the
most essential tool of modern microneuro-
surgery. High magnification, powerful illumi-
nation, and stereoscopic vision constitute the
primary assets of the operating microscope.
Variable magnifications are achieved using an
adjustable zoom system. A surgical field can
be viewed at great depth, in sharp focus and
stereoscopically. This is essential and facilitates
operation at great depth and without a fixed
retraction system. Mirrors or endoscopes can
be used to see structures hidden from view of
the microscope. The counterweight-balanced
microscope was designed by Yaşargil, and cop-
ied by many manufacturers. This creates an es-
sentially weightless suspension of the micro-
scope optics.
A mouth switch (Figure 4-6) permits transla-
tional movement in the 3 planes: left & right,
backwards & forwards, and up & down. This
feature is very useful for focusing and for mi-
nor adjustments of position. With the mouth
switch, the surgery becomes more efficient and
some 30% faster. It avoids the repetitive use
of the hands to make fine adjustments to the
position of the microscope, and facilitates flu-
ency of microneurosurgery. Although the use of
mouth switch is initially demanding to learn,
once you use it you do not ever want to be
without it anymore. Insulated electrical heat-
ing cables around the oculars prevent fogging
of the oculars — a truly helpful device brought
to Helsinki by Prof. Yaşargil. For the mouth-
switch, two surgical masks are placed on each
other before gently biting on the mouth switch.
Two masks are used to prevent saliva from soak-
ing through the mask. Initially, the production
of saliva is quite high and uncomfortable in the
same way as if learning how to play a clari-
net or a saxophone. With the passage of time
and familiarity with the system the production
of saliva decreases dramatically making for a
much more enjoyable surgical experience. But
we still usually use double masks.
The microscope is frequently used for all the
stages of the operation from the dural open-
ing, until the last stitch of the skin. During the
common lateral supraorbital (LSO) craniotomy,
interhemispheric approach or retrosigmoid ap-
proach, it is mostly used after the placement
of the last dural hitch suture and for all the
intradural work. In some of the more extensive
Figure 4-6. Mouthpiece permits the movement of a balan-
ced microscope in 3 planes while allowing both hands to
use microinstruments continuously in the operative field.

78
4 | Necessary or useful tools
approaches such as the presigmoid or the lat-
eral approach to the foramen magnum, already
some steps of the craniotomy are performed
under the microscope. Modern training should
enable the neurosurgeon to work easily and ef-
fortlessly through the operating microscope.
For those in training, closing the wound under
the microscope is one of the most important
ways of learning. The development of hand-eye
co-ordination, execution of fine movements
under high magnification, blind adjustments
for focus or zoom with one hand, gentle mouth
adjustments for position and focus, and ad-
aptation to stereoscopic vision (having depth
perception) under powerful lighting demands
regular exercise.
T&T (Tricks and Tips from Prof. Hernesniemi)
Train with a microscope in laboratory and by
closing the wounds. Learn to use the micro-
scope as if it was a part of your body.
Several supporting features can be added to the
present microscopes such as the image guid-
ance or the fluorescence-based angiography and
resection control. These useful but costly addi-
tions also require special technical skills in the
OR to adjust and maintain the machinery. The
neurosurgeon should be familiar with the com-
mon types of mechanical and electrical failures
of his or her preferred microscope. The present
microscope used by Prof. Hernesniemi is Zeiss
OPMI Pentero (Carl Zeiss AG, Oberkochen, Ger-
many) equipped with mouth switch, ICG (indo-
cyanine green angiography, see 4.5.7.) module
and external Karl Storz H3-M HD camera (Karl
Storz GmbH & Co. KG, Tuttlingen, Germany)
T&T:
Know your microscope and some of its trivial
failures. Service of the microscope is impor-
tant. The light source should be exchanged
regularly. Once the light source died during
an intraoperative aneurysm rupture!
A system for recording surgeries is essential in
the process of learning. Many manufacturers
have incorporated such possibility directly into
their microscopes. The other option is to attach
an external recording device such as a compu-
ter with image capture possibility or a digital
recorder to the microscope. By watching one's
own surgeries later on it is possible to identify
unnecessary steps that slow the progress and
erroneous habits leading to problems.
T&T:
Always check the microscope for your per-
sonal settings before surgery. It takes at
least 50 operations before you fully adapt
to a new microscope.

79
4.5.2. Armrest
Prof. Yaşargil once said to a keen student ques-
tioning some principles: "If you ask me to sign
your book, I rest my hand and the book so I
can sign it nicely. I don't write in the air! To
do microneurosurgery, it is better to rest your
hands on something." The options generally are
to either stand and rest the hands on an arm
support or to sit in a chair with armrests.
The armrest can be improvised, like the edge of
the bed in the sitting position, or the edges of
a Sugita frame. Usually it is in the shape of a
standing platform, which is spring loaded and
has a ball and socket joint at its base. This al-
lows the surgeon to manipulate its height and
angle of tilt as illustrated (Figure 4-3 - page 75).
T&T:
There are few surgeons who do well without
an armrest. Prof. Peerless was one of them.
With experience the need for armrest lessens,
it may give only psychological support. This
has been verified by me during some visiting
surgeries in OR's lacking an armrest.
4.5.3. Bipolar and diathermia
Bipolar and monopolar cautery are nowadays
essential devices in any kind of surgery. It is
necessary to be well familiar with the settings
of the particular bipolar device used. In Hel-
sinki we use Malis bipolar system (Codman,
Raynham, MA, USA) The settings are generally
50 for extracranial work, 30 for intracranial
work, and in coagulation of small vessel or an-
eurysm reshaping as low as 20–25. In highly
vascularized tumors the setting is usually 50 or
more, up to 70, higher than for other intracra-
nial work. Diathermia can be efficiently used to
strip attachments of muscles from bone while
doing hemostasis at the same time. It is espe-
cially helpful in posterior fossa approaches and
posterior or lateral approaches to the cervical
spine.

80
4.5.4. High speed drill
The high speed drill allowing use of various drill
heads at up to 100,000 RPM has been almost
standard in all advanced neurosurgical units. It
allows for a faster, cleaner craniotomy, requir-
ing as few as one access burr hole. We prefer
electric drills because they are light, easy to
use, fast, safe, and independent of the pres-
surized air supply. At least in our experience,
the pressurized air supply can easily vary in the
hospital network. Earlier the pneumatic drills
were stronger with more torque, but nowadays
with the modern electric drills there is no real
difference. High-speed drilling is performed
under the operating microscope. The burr is
moved with precision by the dominant hand
while controlled by proprioception, vision, and
the foot pedal. This interplay should be trained
on cadaveric work in laboratory. Using both
hands to hold the drill and stabilize it is not
recommended as it is clumsy and easily leads
to greater instability than expected. Instead,
the left hand with suction is actually used to
guide the drill into a proper position and the
drill is stabilized by resting the right palm at
the edge of the operative field. All coverings
in the area are removed to prevent them from
being caught by the drill and damaging sur-
rounding structures by windmill action.
In Helsinki we usually use the Stryker electric
drills (Stryker Corp., Kalamazoo, MI, USA) They
are heavier than some other high-speed drills,
but they are very powerful which suits well
with the way how we use the drill. For every
case there is the standard set used (Figure 4-7).
First drill head (trephine) allows the placement
of the burr hole, the second containing the
footplate is used for the craniotomy. The third
drill head is the same craniotomy blade as the
second but the drill guard does not contain the
footplate so that the drill bit can be used to
thin down a bone ridge before it is lifted and
cracked. The same drill bit is used to make small
holes for tack-up sutures. The fourth drill bit is
a cutting ball drill head which allows drilling
and smoothing the edges of a craniotomy for
access towards the base of the skull (as com-
monly in the lateral supraoprbital craniotomy).
The last drill head is a diamond drill head,
which aids in "hot drilling". This is where the
bone is drilled without irrigation, resulting in
heating and cessation of all bleeding from the
bony surface.

81
A B
DC
Figure 4-7. The standard drill tips used in Helsinki for craniotomy. (a) Craniotome blade with a footplate. (b) Same cranio-
tome blade without a footplate, used for tack-up suture holes and thinning of bone near the skull base. (c) Cutting ball tip,
5.5 mm. (d) Diamond ball tip, 5.5 mm.

82
4.5.5. Ultrasonic aspirator
The ultrasonic aspirator is made in different
forms by different manufacturers. The one used
in Helsinki is Stryker Sonopet (Stryker Corp.,
Kalamazoo, MI, USA). With a variety of oscil-
lating heads it can be used on soft (tumor)
or hard (bony) tissue, to focally and precisely
destroy tissue and remove it. Soft tumors can
be gently shaved down and excised from e.g.
the fourth ventricle. Even more usefully, bone
can be cut from the base of skull with precision
and without the kicking and shaking associated
with the high speed drill. There is no danger
of catching nearby cottonoids as there is with
a rotating drill head. This is very practical in
tight areas surrounded with crucial structures,
such as when removing the anterior or pos-
terior clinoid process. The machine has vari-
able settings for power, irrigation and suction,
and makes bone removal at the base of skull
much simpler and safer. But in the same way
as with high-speed drill, laboratory training to
get accustomed with the appropriate settings
is mandatory.

83
4.5.6. Fibrin glue
Fibrin glue is a tissue sealant which has been
used widely for many years in different surgi-
cal disciplines including neurosurgery, cardiac,
ENT, general surgery and even orthopedics. Prof.
Hernesniemi started to use fibrin glue exces-
sively during the 1980's. Fibrin glue simulates
what happens in the physiological process of
wound healing and closure. It has hemostatic
properties and also can be used to close tis-
sue defects such as the dura (augmented with
Surgicel or muscle or other materials) as long
as the area is dry and there is no significant
pressure gradient or flow across the defect. It
is a viscous liquid that settles and covers tis-
sues well. It is a highly concentrated fibrinogen
aprotinin solution (30 times the concentration
of fibrinogen vs. human plasma; 75–115 mg/
ml vs. 2–4 mg/ml in human plasma) that also
contains factor XIII and a solution of thrombin
and calcium chloride. The factor XIII causes the
cross linking of fibrin. The type of fibrin glue used
in Helsinki is Tisseel (Baxter, Deerfield, IL, USA).
In Helsinki, fibrin glue is widely used and comes
in a ready-made form. This is stored in a freezer
at a temperature of -10 °C. It costs approxi-
mately 100 euros for each 2 ml package. The
alternative available to most other countries
is the unprepared 5 ml package that takes 20
minutes to prepare. This laborious preparation
often discourages its use, and the ready-made
preparation although expensive, has clear ad-
vantages.
Fibrin glue is used in Helsinki in the following
places and situations:
• In the extradural space at the beginning of
a craniotomy to prevent later epidural hem-
orrhage in the middle of an operation
• In the bony hemorrhage
• In sealing mastoid air cells
• In sealing small dural defects in the spine
and cranium
• For its adhesive effect at times where a muscle
or fat graft is used to seal a defect or rein
force a tissue wall or vessel
• In the cavernous sinus
• In skull base bleedings
• For closure of carotico-cavernous fistulae
• For tumor and AVM vessel embolization
intraoperatively by direct injection
• To stop venous hemorrhage from small dural
sinuses
Fibrin glue stops effectively bleeding from the
region of the cavernous sinus or the tentorium
with small injections into the intradural venous
plexus. This does not appear to cause any sig-
nificant or extensive thrombosis beyond the re-
gion of interest. The economic use of fibrin glue
has clear advantages and benefits especially
when trying to stop hemorrhage from the cav-
ernous sinus during transcavernous approaches
or extradural approaches to the base of skull.
Although the fibrin glue is expensive, it saves
operation time and need for blood products. By
avoiding many hemorrhagic complications, it's
use pays more than well back.

84
4.5.7. Indocyanine green angiography
Microscope integrated near-infrared indocya-
nine green video angiography (ICG) has been
used effectively in Helsinki since 2005. This
technology allows the assessment of the cer-
ebral vasculature in the arterial and venous
phase under the magnification of the micro-
scope (Figure 4-8). On request, the anesthesi-
ologist gives an intravenous injection of indo-
cyanine green. A dose of 0.2 to 0.5 mg/kg is
recommended. Subsequently the field of inter-
est is illuminated with near-infrared light. Real
time and dynamic angiographic images are
then displayed and recorded. The images show
the arterial, capillary and venous phase of flow
in the area of interest. A playback facility is
available if needed.
The technology is considered by some to be es-
sential for high quality vascular surgery. In an-
eurysm surgery it allows the confirmation and
recording of total exclusion of the aneurysm
from the circulation. Also the parent artery,
major branches and perforating vessels can be
visualized. If any adjustment to the clip posi-
tion is required for better exclusion of the an-
eurysm, and, more importantly, to restore flow
in an occluded vessel or perforator, it can be
done immediately. Its use is simple, practical
and can be repeated.
Like all technology it is not 100% sensitive or
specific. Caution is required when assessing
flow remnant in a clipped thick-walled an-
eurysm. In such cases flow may not be seen
through the thick wall, and the surgeon can be
faced with an unpleasant situation if he or she
punctures such an aneurysm which is still fill-
ing. The use of ICG can be adopted for analysis
of flow in AVMs, and localization and analysis
of anatomy in other vascular pathologies e.g.
hemangioblastomas and cavernomas.
Figure 4-8. (a) Left MCA bifurcation aneurysm in visible light seen through the microscope.
A

85
(b) The same field seen with ICG. (c) The same view after perfect clipping of the aneurysm.
B C
4.5.8. Microsurgical doppler and flowmeter
Doppler allows a qualitative measurement of
blood flow in a cerebral vessel or even aneu-
rysm. This is done via a hand held probe the tip
of which can be placed on a small vessel or an-
eurysm to be studied. Flow can be detected and
conveyed as a pulsating bruit type of sound.
However, the interpretation of the findings
may be difficult. Loss of pulsating sound can
mean vessel occlusion, but it can also be just
due to a poor probe contact or wrong angle
with respect to the vessel. On the other hand,
sound does not necessarily mean normal flow,
it can be also caused by stagnating pulsation
in arterial occlusion. There are more advanced
types of flowmeters that measure the flow
qualitatively. In Helsinki, we use them usually
during bypass surgery. These flowmeters pro-
vide objective measurements of blood flow in
terms of volume/time. However, their efficacy
and use is very much operator dependent and
requires more expertise in interpretation of the
results. But still, micro-Doppler and flowprobes
are yet another useful adjunct in the vascular
neurosurgeon's armamentarium.

86
4.5.9. Neuronavigator
Neuronavigation is routine in many practices,
and intraoperative imaging may become so in
the future. However, it is important to study the
preoperative images very carefully to identify
landmarks such as the earlobes, coronal and
lambdoid sutures, inion, sylvian fissure, central
sulcus by inverted omega hand area, confluens
sinuum, straight and transverse sinuses, etc.
Neuronavigators may be out of order or too
expensive for the institution. Quite frankly, to
know neuroanatomy well is by far more impor-
tant than to own and use a navigator. Careful
measurements along the landmarks, the pa-
thology, and the intended trajectory can usu-
ally be transferred to the scalp with acceptable
accuracy. Many approaches, such as surgery for
cerebral aneurysms and most extraparenchy-
mal brain tumors, are so dense with anatomical
landmarks that no neuronavigation is needed,
just operative experience. That said, there are
certain pathologies, where the use of neuro-
navigation is of great help. These would be
small, subcortical lesions, which are not close
to any distinct anatomical landmarks, such as
cavernomas and deep AVMs. Furthermore, in
distal MCA and pericallosal aneurysms use of
the navigator can be most helpful in finding
the aneurysm. Also in parasagittal, falx and
convexity meningiomas the neuronavigator
may be of help in planning the craniotomy of
appropriate size and location. But the neuro-
navigator should never be trusted blindly due
to the effect of brain shift once the dura is
opened and CSF released. For the neuronavi-
gator to be used effectively one needs to be
familiar with the setup, use it routinely and be
well aware of the limitations of the system. Us-
ing the stereotactic frame can be an option if
the neuronavigator is not available, but this is
usually more cumbersome.
Figure 4-9. OR setup for intraoperative DSA; Dr. Riku Kivisaari performing the angiography.

87
4.5.10. Intraoperative DSA
Although ICG has significantly lowered the fre-
quency with which intraoperative DSA is being
used, there are still special situations where it
is very helpful. These include complex, heavily
calcified, large or giant aneurysms, bypass sur-
gery, AVM surgery or surgery for dural arteriov-
enous fistulas (DAVFs). To perform DSA intraop-
eratively in the OR one needs a C-arm with an
option for performing subtraction angiography
(Figure 4-9). This is nowadays standard in all
modern C-arms. However, where the difficulty
arises is the actual technical performance that
requires excellent collaboration between the
neurointerventionalist, OR technician manipu-
lating the C-arm and anesthesiological nurse
moving the operating table. Since most operat-
ing tables are radio-opaque, the patient's head
is fixed in a radio-opaque frame and there is
a lot of other hardware around, standard pro-
jections can be seldom achieved. Instead, one
usually has to rely on only one or possibly two
suboptimal projections. Reading such images
requires a lot of experience from the neurora-
diologist, especially due to the pressure of time
and the surroundings in such a situation. But
at the same time the information obtained can
be very helpful in continuing, or finishing the
surgery. Catheterization can be performed be-
fore the start of the surgery in the angio suite,
which is technically easier but more time con-
suming. In this case, the catheter attached to
irrigation pump is left in place for the dura-
tion of the procedure. We use this technique in
clearcut situations when the need of intraop-
erative DSA is known already at the beginning
of the surgery. We do not leave catheters in
vertebral arteries, only in carotid arteries, since
the risk of vessel wall damage and thromboem-
bolic complications is much higher for verte-
bral arteries. The other option is to catheterize
the patient during the surgery on the operating
table, which is technically much more demand-
ing especially if the patient is not in supine po-
sition, e.g. in lateral park bench position. We
have also tested radio-translucent head fixa-
tion frames made e.g. from carbon fibre. The
problem with them, beside the high cost, was
that they could not withstand normal everyday
use and broke very easily.
T&T:
You can navigate by experience, but even the
best fail from time to time! Use navigation in
all critical lesions, especially in subcortical
ones.
T&T:
Intraoperative DSA should be used in all com-
plex aneurysms and large AVMs. Intermittent
balloon occlusion of ICA, with or without suc-
tion, has saved lives in large ICA aneurysms.

88
4 | Microinstruments
4.6. MICROINSTRUMENTS
The microneurosurgical instruments either use
a single shaft, such as suction or microdissec-
tors, or two shafts, such as the bipolar forceps,
microscissors or aneurysm clip applicators. The
instruments are held like a pen; i.e. with the
distal aspects of the fingers and thumbs. It is
the fine movement from the distal joints that
do most of the work. This way the movements,
whether subtle or significant, are controlled
and well regulated. The instruments are held
using suitable points of grip along their shaft
and the arms are rested using the adjustable
T-shaped forearm support. The ulnar sides of
the fingers are placed on the Sugita frame or
the craniotomy edge for maximum stability.
The array of microinstruments should allow
this hand position by various lengths such as
short, medium, long, and very long — more so
with two-shaft instruments. To minimize phys-
iologic tremor one should always try to use
the shortest version of the instrument appli-
cable to the particular situation. There should
be clear visualization of the tips of the instru-
ments. Often the first difficulty encountered
for residents and those beginning training is
how not to allow their hands to obstruct the
visual working channel when looking through
the microscope.
T&T:
Use appropriate instrument length, usually
the shortest possible to maximize control
and to minimize tremor.
T&T:
Keep your hand/fingers in specific posture
when asking for a particular instrument, it
will help your scrub nurse to anticipate your
next move and to place the instrument
always in a standard way into your hand.
There are many microneurosurgical sets, such
as the Yaşargil, Rhoton or Perneczky set, and a
large array of bipolar forceps as used by Prof.
Yaşargil. They are all excellent, and serve a good
purpose. The surgeon should use whatever he or
she likes, and there are no commercial prefer-
ences suggested. In Helsinki style microsurgery,
there are 11 basic instruments that are used
in the vast majority of situations (Figure 4-10).
These consist of four bipolar forceps (longer and
short, sharp and blunt tipped), microdissector,
straight microscissors, aneurysm clip applica-
tor, straight blunt steel needle for irrigation,
and three suction tubes (long, medium size,
and short) which allow regulation of the suc-
tion power through three holes (earlier on, one
hole was factory made and the two additional
holes self made) by sliding the thumb. By limit-
ing the number of instruments in the standard
setup to only those that are necessary, one can
save a lot of time. With large microinstrument
sets, a lot of time is lost in the process of: (a)
selecting the instrument in mind, (b) asking for
the instrument, (c) searching for the particu-
lar special instrument among so many similar
looking ones, (d) placing the instrument into
the hand of the surgeon, and (e) finally moving
the instrument into the operative field. As this
process can be repeated hundreds of times dur-
ing a single surgery, it is reasonable to simplify
it as much as possible. But if required, also less
frequently used instruments or their special
versions should be easily available.

89
Microinstruments | 4
Figure 4-10. The basic set of 11 instruments. Four bipolar forceps (longer and short, sharp and blunt tipped), microdissector,
straight microscissors, aneurysm clip applicator, straight blunt steel needle for irrigation, and three suction tubes (long,
medium size, and short).

90
4 | Some habits in preparation and draping
4.7. SOME HABITS IN PREPARATION
AND DRAPING
Maybe a better word to use than habit is con-
sistency. A criticism of consistency is that it is
unimaginative or just boring. Our philosophy in
Helsinki is that until you find some better way
to do a certain thing, don't change your ways.
Find a good method and stick to it. The people
we work with in the OR appreciate our consist-
ency. A significant lack of consistency can even
generate anxiety and fear in those around us.
Consistency goes hand in hand with a system-
atic approach. It should not be confused with
what is customary or traditional. It should be
based on logic, reason and experience. This way
assistants around you know what to get for you,
how to help you and what to expect. Not just in
anticipating what instruments you use next or
your surgical technique. But even their familiar-
ity with how you think, talk and behave allows
them to understand you and assist you better.
T&T:
In your operations, change only one thing at a
time! You can be creative, but proceed slowly.
This is probably best exemplified by how Prof.
Hernesniemi positions the patient, drapes and
then carries out the appropriate craniotomy in
the same predictable way. These steps include
the following:
1. Upon arrival in the OR he checks the micro-
scope optics, balance and mouthpiece.
2. He reviews the radiological images before
and then once again after checking the
microscope, not least to double-check the
side of the lesion. This is very important for
the position of the surgeon, scrub nurse,
microscope and the assistant.
3. The cases where a supine position is neces-
sary the head is elevated above the heart
by using a strong round pillow under the
shoulders to elevate the upper chest. The
exact positioning for each approach is
reviewed in Chapter 5.
4. The head is first fixed in the Sugita head
frame by four pins. Then all the joints are
released and the final positioning of the
head is performed in accordance with the
operative approach, angle of approach and
site of pathology. Only then all the joints
are finally fixed.
5. The appropriate incision site is shaved
with an electric razor.
6. A hand held razor is used for a finer shave
and then gel soap ("Mäntysuopa", a tradi-
tional soap used in Finland) is applied to
clean the area and comb the hair back
away from the wound with the hands.
7. Then Prof. Hernesniemi leaves the OR to
wash his hands from the soap, returning to
clean the wound area using swabs soaked
in 80% alcohol. The wound region is
repeatedly cleaned, ensuring all dirt parti-
cles, oily secretions and skin debris are
wiped away.

91
Some habits in preparation and draping | 4
8. The incision is drawn using a disposable
sterile pen.
9. The wound is infiltrated using usually
approximately 20 ml of a solution consist-
ing of a 1:1 combination of 0.75% ropi-
vacaine and 1% lidocaine with 1:100 000
adrenaline.
10. Then large abdominal swabs are laid out
isolating the incision area. The swabs are
held in place and the incision area is cov-
ered using a large Opsite dressing, which is
also placed over the sides of the Sugita
frame and pins to fix it in place. The ground
below the draped region is wiped clean
by Prof. Hernesniemi himself. This practice
is based on a fall on a slippery floor during
a stereotactic procedure in the 70's. The
scrub nurse commences the rest of the
draping procedure.
T&T:
While preparing the positioning and the opera-
tive area, the different steps of the upcoming
operations are going through the neurosur-
geon's mind. Going through a known routine
helps to focus and calm down. Few kind words
with the scrub nurse and others ensure readi-
ness for the surgery, and relax the atmosphere.

92
4 | General principles of craniotomy
Figure 4-11. (a) The curved „Jone“ dissector, used to separate the dura from the inside surface of the skull.
(b) The Yaşargil-type flexible dissector useful for larger bone flaps.
A B
4.8. GENERAL PRINCIPLES OF CRANIOTOMY
The scalp is minimally shaved, washed, and
then infiltrated along the drawn incision line
by an anesthetic and vasoconstrictive solution.
In the approaches to the anterior and middle
skull base, direct incision through the skin and
temporal muscle and turning a single-layer flap
have been proven safe for more than 25 years.
There is no temporal muscle atrophy or injury
to the upper branch of the facial nerve. Strong
retracting force of the Sugita frame fish hooks
gives a wide exposure of the Sylvian fissure and
the skull base without large skull-base resec-
tions and at the same time controls the scalp
and muscle bleedings, which are swiftly dealt
with using bipolar coagulation. Most cranioto-
mies require only one burr hole and cutting of
the bone flap with a craniotome. The adherence
of the dura to the bone increases with age,
and additional burr hole(s) may be needed. A
special curved dissector ("Jone", Figure 4-11a),
designed by a hospital technician from Kuopio
and carrying his name, is useful for adequate
dissection. In case of a larger bone flap, flex-
ible Yaşargil-type dissector is useful also (Fig-
ure 4-11b). The major dural sinuses are more
easily detached from the bone by placing the
burr holes exactly over them rather than later-
ally. Over the regions with thicker bone or over
sinuses bone is thinned down using craniotome
without the L-shaped footplate. Afterwards, it
is possible to crack the bone along this thinned
ridge. Craniotome is also used for drilling sev-
eral holes along the craniotomy edge to be
used for tack-up sutures during closure. More
bone is then removed with a high-speed drill,
working towards the desired direction. Small
bleeding from the bone is stopped using a
diamond drill without irrigation, the so-called
"hot drilling".
A common comment by visitors is the lack of
profuse scalp bleeding during the surgery. This
is certainly because of good anesthesia keeping
the blood pressure normotensive, but mainly
due to local infiltration using plenty (up to 20
ml) of 0.75% ropivacaine and 1% lidocaine with
1:100 000 adrenaline several minutes prior to
the incision. Additional means to tackle bleed-
ing from the scalp is the use of disposable Raney
scalp clips (Mizuho Medical Inc., Tokyo, Japan)
at the incision line and heavy retraction/ten-
sion in the scalp flap either with spring hooks
or sufficient tension in linear wound spreaders.
Any further hemorrhage points are taken care
of vigorously during the approach. Not only
does it save much time and prevents distrac-
tion during the crucial parts of the operation
but also during the closure. Craniotomy should

93
General principles of craniotomy | 4
not be performed before bleeding from the
more superficial layers has been taken care of.
Dura is opened only after careful hemostasis.
This is one of the steps that have to be finished
before moving forward. Venous oozing from
epidural space can be stopped by combination
of Surgicel, fibrin glue, and lifting sutures. Per-
manent tack-up sutures are placed normally
at the end of the procedure once the dura has
been closed as they prevent additional stretch-
ing of the dura to cover small gaps that may
be needed during closure. In case of serious
epidural bleeding, the permanent tack-up su-
ture may be placed already before opening the
dura. Injecting saline into the epidural space
makes Surgicel to swell stopping epidural ooz-
ing more effectively than simple Surgicel tam-
ponade. The area surrounding the craniotomy
is covered with swabs dipped in hydrogen
peroxide and a green cloth is attached to the
craniotomy edges with staples. The green cloth
is used to increase colour balance in the opera-
tive field for obtaining a better image from the
microscope's video camera, and, quite frankly,
the operative field just looks cleaner and better.
In general, the operative field is saturated with
red colour and especially in older microscope
cameras that may cause a significant problem
in image quality. The other reason is to de-
crease the amount of reflected light from the
white swabs, which under microscope's high
intensity lamp can be almost blinding. The dura
is opened usually in a curvilinear fashion in one
or several pieces with wide base(s) and lifted
up with many tight sutures to form a tent-like
ridge along the opening preventing any further
oozing from the epidural space. These sutures
under tension keep the green cloth in place and
they are fixed onto the surrounding drapings
with hemostats (Crile, Dandy or other).
T&T:
Never continue surgery before stopping
all the bleedings!
T&T:
Keep the operative field as clean as possible. It
will make visualization of anatomical structures
easier and leads to better and faster surgery.

94
4 | Basic microsurgical principles of Helsinki style microsurgery
4.9. BASIC MICROSURGICAL PRINCIPLES OF
HELSINKI STYLE MICRONEUROSURGERY
4.9.1. Simple, clean, fast and preserving
normal anatomy
The whole concept of microsurgical principles
of Helsinki style microneurosurgery can be
summarized into the words "simple, clean, fast,
and preserving normal anatomy".
Simple refers to doing only what is really neces-
sary and trying to achieve this goal by as little
effort as possible. Interchanging instruments is
kept at a minimum, the repertoire of instru-
mentation is kept very standard and limited. In
this way both the neurosurgeon and the scrub
nurse become familiar with the instruments
faster and certain steps of the surgery can be
standardized. In addition, the same instrument
can be used for several different tasks as ex-
plained further on.
Clean, bloodless environment is the key factor
for a successful microsurgical operation. With
high magnification, even a tiny bleeding can fill
the whole operating field making orientation
impossible. Hemostasis throughout the proce-
dure is of utmost importance but in addition
one should also choose such surgical strategy
which prevents bleeding from occurring in the
first place. This can be achieved by selecting
the right approach and sticking to the natural
cleavage planes and boundaries. Every bleeding
should be stopped as soon as it is detected be-
fore moving further. In addition, irrigation can
be used very liberally to flush out any blood
clots or other obstructions from the operative
field.
T&T:
Water clears the operative field and the mind,
and makes a break in the operation. When you
need to think how to proceed, irrigate.
Preserving normal anatomy comes with re-
specting natural tissue boundaries and cleav-
age planes. Orientation under high magnifica-
tion becomes much easier when the dissection
is directed along anatomical structures keeping
them intact. Anatomical structures should be
invaded only when it is absolutely necessary
for the procedure. One should always choose
the approach that is the least invasive and
preserves the normal anatomy to minimize the
possibility of new postoperative deficits.
Fast does not mean that things should be done
in a rush, rather it is the effect of the previ-
ous three factors. The majority of time during
surgery is lost by poor planning, wrong or inap-
propriate approach and by tackling undesired
situations such as bleedings. Correct surgical
strategy and pre-emptive evasion of problems
brought by experience increase the speed of
surgical performance over time. It is easier to
maintain proper concentration during a shorter
procedure, one does not make mistakes as eas-
ily, and in addition, it becomes also more cost
effective as one can perform more surgeries in
a given time. But especially at the beginning
of the career one should concentrate more on
quality of performance than speed. The speed
will come with experience.
T&T:
In many of the so-called "heroic and long-
lasting" surgeries, most of the time is actually
spent on correcting one's own mistakes. Espe-
cially to stop bleedings caused by the surgeon
himself.

95
Basic microsurgical principles of Helsinki style microsurgery | 4
4.9.2. Movements under the microscope
It is considered by some as sacrosanct to use
microinstruments only under direct micro-
scopic vision. They remove all the instruments
completely out of the wound and away from
the vicinity of any crucial and important struc-
tures, while their eyes are not on the operative
field. The worry is that if you have not got an
eye on it, then you cannot be sure what your
hand or instrument is doing. However, this
slows the surgery down as every instrument
has to be repeatedly brought into the opera-
tive field. To make the surgery more fluent and
effective, one needs to master the technique of
the so-called "blind hand". It means movement
without direct visual control. The first blind
maneuver easily mastered by a microsurgeon
is the change of instrument by the right hand.
That means the right hand instrument is taken
out, and while looking down the microscope
the awaiting hand is given the next instrument
by the assisting nurse (Figure 4-12). This is rel-
atively easy as vision is maintained on the more
crucial hand and instrument in the surgical
field. A more demanding but even more useful
adaptation of the blind hand technique can be
seen in situations when an instrument is kept
in the surgical field without direct vision, while
the neurosurgeon casts his or her eyes away
from the microscope and looks elsewhere. This
may be to take e.g. a cottonoid, or adjust the
microscope (Figure 4-13). This is usually done
only for brief moments but the remaining hand
and the instruments should be kept in the ex-
act same position as before.
In Prof. Hernesniemi's style the pace and flu-
ency of surgery is evident with the use of the
blind left or right hand in the operative field.
It is a manifestation of confidence and fluency
possessed to do this regularly and flawlessly.
Figure 4-12. The right hand waiting for an instrument, while keeping the eyes on the microscope.

96
The task is performed subconsciously, similar to
the way a guitarist plays very fast and intricate
notes without looking at his fingers. The abil-
ity comes after much practice and experience.
After a while when you are so familiar with
your senses and ability you can speed up for
good reason. And if you are keeping an instru-
ment still and steady then you may not need to
visually check the position of your instrument
at each and every moment. You are sure from
other non-visual senses where it is. A steady
pivotal left hand (and occasionally right hand)
can significantly shorten temporary clipping
times, lessen the need for re-exposure or re-
peated dissection and retraction. What it does
allow is to move and adjust position of the
microscope or armrest, take cottonoids or Sur-
gicel, and even choose the best aneurysm clip
by visual inspection. This while keeping the left
hand absolutely still near crucial structures,
while the body may even pivot around the left
hand instrument.
Also the interchangeable right and left hand
function as small retractors is beneficial. This
is very useful, for example, in fast and smooth
subfrontal dissection for the opening of the
lamina terminalis. When you are faced with
an angry swollen brain with hydrocephalus
or hemorrhage, it is better to be fast. To make
progress, avoid periods of non-action - yet hur-
rying is not a good thing either. If there is one
safe and easy move that can compensate for
two, then this move should be carried out. The
speed actually comes from leaving out the un-
necessary moves and avoiding possible prob-
lems, not from doing things in a hurry.
This style demands strength, stability, appre-
ciation of the surgical field, depth perception,
feel for tissues, and a joint position sense. The
neurosurgeon can hold the sucker to suck, re-
tract, or maintain tissue planes. Under direct
vision it can be a consistent reference point in
the surgical field after blind change of instru-
ments with the right hand. After much practice
and familiarity the microneurosurgeon com-
bines the use of the visual senses, feel for tis-
sues and proprioception to give a high sense
of awareness regarding surgical dimensions,
depth of wound and relationship of instru-
ments to close and crucial structures. A fast
and excellent microneurosurgeon schooled in
Helsinki style can place a combination of suck-
er, microscissors or bipolar into a small wound
and move with precision and fluency around
small crucial nerves and vessels while perform-
ing dissection, cutting, coagulating, excising,
occluding or even suturing in the depth; this
without disturbing any important structures
and without the repeated withdrawal and re-
entry of the same instruments and unnecessary
gaps of doing nothing. Being aware of such
techniques helps training. It is best appreci-
ated by watching many experienced surgeons
"live" in the OR, paying attention to their body
posture and movements, hand movements, and
also the actual microsurgical technique under
the magnification of a microscope.

97
Figure 4-13. Looking away from the microscope, while the left hand (holding a suction) remains in the operative field.

98
Figure 4-14. Adjusting the microscope with only the right hand.
This can be done even with the right hand still holding an instrument.
4.9.3. Moving the microscope
One of the distinct styles of Helsinki style
microneurosurgery is the constant movement
of the microscope. With the mouthswitch it is
possible to move the microscope in the hori-
zontal plane and up and down (Figure 4-6 -
page 77). Especially the vertical movement is
crucial since it is used for focusing. With fixed
focal distance, small vertical movements with
the mouth switch are used to focus inside the
deep operating field. Also small translational
movement in plane is carried out using only
the mouth switch. All this movement is nec-
essary especially when operating under a very
high magnification. Autofocus is of no use with
the mouth switch; rather, it moves the micro-
scope out of focus all the time. With the right
thumb the neurosurgeon can change zoom or
focal distance on the right handle of the mi-
croscope blindly while stabilizing the micro-
scope with the mouth switch. Tilting and chang
ing the viewing angle requires also the right
hand. But even here with the mouth switch as
second contact point, the microscope can be
turned with only one hand while the left hand
and suction is kept in the visual field as a pivot
point (Figure 4-14). The standing posture gives
very much freedom for even rather extreme
and fast changes of viewing angle. Eventually,
when watching a neurosurgeon who has mas-
tered this technique, it looks like he or she is
dancing around the patient while the micro-
scope is floating.
T&T:
A mouthpiece is one of the great introductions
of Professor Yaşargil. It is surprising that not
every microneurosurgeon is using it!

99
Figure 4-15. For a right-handed neurosurgeon, left hand is mainly used for controlling the suction,
the left hand for the other instruments.
4.9.4. Left hand – suction
For a right-handed surgeon, the suction is in
the left hand (Figure 4-15). The suction can be
the most dangerous instrument if it is not used
properly. But in trained hands its use allows not
only suction, but gentle inspection, retraction
and dissection. Even the varieties of sounds
made while using its suction function gives the
surgeon, assistant and scrub nurse informa-
tion about the state, consistency, nature and
character of the fluid or tissue at its tips. The
strength of the suction should be regulated by
the use of the thumb sliding across the three
holes at the base of the suction tube (Figure
4-16). The staff in OR should be ready to quick-
ly adjust the strength of the suction. The tube
attached to the metal sucker should be of good
quality (e.g. silicon rubber), light, and flexible
such that it does not over-burden or hinder the
movements of the left hand.
We use mostly two to three different diameters
of suckers with three different lengths available
(short, medium and long). A dry sucker shaft or
one stained with coagulated blood may cause
it to stick to the surrounding brain. Instead, it
should be clean and slightly wet to facilitate its
function as a gentle and most useful retractor.
Very importantly, the tips of the suction should
be checked regularly to ensure that there are
no sharp edges caused by, e.g. use of high-
speed drill. The use of regular saline irrigation
or washout with a handheld syringe cannot be
overstated. Frequent irrigation prevents instru-
ments from adhering to tissues, removes debris
and clears the picture seen in the mind of the
surgeon. The use of irrigation is discussed fur-
ther in section 4.9.10.

100
Figure 4-16. Three holes at the base of the suction tube enable controlling the suction force by sliding the thumb.
4.9.5. Right hand
The right hand is generally for the bipolar
forceps, but also for the microdissector, mi-
croscissors, clip applicators, drills, ultrasonic
aspirator and Sonopet alike. There are various
styles and methods of using the right hand in
microneurosurgery, which becomes evident
when observing different neurosurgeons at dif-
ferent departments. Some make little use of
the bipolar forceps for dissection and instead
use the dissectors or even two jeweler's for-
ceps to a much greater extent. The right hand
is also used to adjust microscope settings and
to move the microscope. In the beginning it is
easier to perform these adjustments with an
empty hand, but with time one learns to grab
the handle of the microscope while still hold-
ing bipolar forceps in the right hand.

101
4.9.6. Bipolar forceps
In Helsinki style microneurosurgery the bipolar
forceps are used frequently and effectively for
inspection and dissection of structures and an-
atomical planes. The bipolar forceps opens by
itself, and as long as the opening force is suit-
able, it can be used to open arachnoid planes,
separate membranes, macerate tumor tissue in
preparation for debulking, dissect sharply in-
side glioma tissue using the coagulation func-
tion, and obviously simply to coagulate tissue.
There are mostly two lengths of bipolar forceps
used by Prof. Hernesniemi. For both lengths
there are sharp and blunt tipped versions of the
forceps available. Other lengths are available if
needed but most of the time these two lengths
are sufficient. In situations where coagulation
is repeated over and over, like in glioma or AVM
surgery, two or more forceps of the same kind
are interchanged and cleaned repeatedly by the
scrub nurse to save time. The bipolar forceps
has several possible functions. It can be used
as dissector by using its tips, it can macerate
and coagulate tumor tissue and finally its shaft
can function as a microretractor. Clean tips
are essential for dissection of natural cleavage
planes under high magnification. The angled or
curved bipolar forceps help in places that are
hard to reach behind a corner, such as the ol-
factory groove.
The use of the bipolar forceps for blunt dissec-
tion is consistently demonstrated in most of the
microsurgical videos that show the approach
to an aneurysm and tumor. It is probably best
seen during opening of the Sylvian fissure, dur-
ing dissection in the cerebello-pontine angle,
or during dissection in the interhemispheric ap-
proach. There is a natural tendency for the bi-
polar forceps to open and this is used effective-
ly to gently separate tissue planes. This is done
as blunt dissection using blunt tipped bipolar
forceps between tissue planes e.g. arachnoid
layers, or tumor/brain interface. Or it is done
as sharp dissection by using the sharp tipped
bipolar forceps to cut across tissue planes like
when opening the lamina terminalis. The bipo-
lar forceps is also used to assess and gauge the
consistency of a vessel by gently pinching the
vessel, or assessing the consistency of an an-
eurysm or other lesion by resting the tip of the
bipolar forceps on it.
When coagulating, it is important to place a
little gap between the tips of the forceps to al-
low adequate coagulation, and also preferably
to use short and small bursts of coagulation
to lessen the incineration and charring effect
which so often covers the bipolar forceps tips.
This technique of "open-close" or "to and fro"
or "oscillating" coagulation as well as "hop-
ping" along the length of a vessel where co-
agulation is required is basic and useful, as is
the use of small amounts of irrigation. It allows
better coagulation and prevents the sticking of
the bipolar tips. "Dirty coagulation", a special
technique in AVM surgery or in highly vascu-
larized tumors, is to coagulate tiny perforators
with almost nonexistent vessel wall by taking
little surrounding brain tissue between the
tips of the forceps and coagulating the vessel
through this tissue mass.

102
Figure 4-17. Cottonoids and pieces of Surgicel fibrillar placed on a pad situated next to the operative field; continuously
replenished by a scrub nurse during the operation.
4.9.7. Microscissors
The microscissors are used to delicately and
swiftly separate arachnoid membranes and
layers, not just by use of the cutting blades,
but also by using the side of the closed tips.
The tips of the microscissors are often used
for gentle retraction of small or large vessels,
cranial nerves or even inspection of an aneu-
rysm. Such ability to gently and precisely use
common instruments for multiple tasks avoids
unnecessary interchange of many microinstru-
ments. This prevents the crowding of the nurses
tray and shortens the operation time.
4.9.8. Cottonoids
The cottonoids or patties should be readily
available in different sizes close to the opera-
tive field. We usually prefer cottonoids without
strings as the strings get easily twisted or en-
tangled to each other and they are frequently
accidentally pulled out (Figure 4-17). Also,
the strings easily obstruct part of the opera-
tive field especially in deeper locations. On the
other hand, using cottonoids without strings
requires always meticulous checking of all the
operative field that some small cottonoid is not
left behind, especially in large resection cavi-
ties with structures blocking the view.
The cottonoids can be used for several
purposes:

103
• To facilitate non-traumatic suction on
neural tissue and near cerebral vessels
• To protect crucial neural or vascular struc-
tures during dissection and approach. For
example during the opening of the dura to
protect the cortex
• To protect neural tissue from the sharp edge
of a retractor blade, sucker or bipolar forceps.
• To cover the surrounding region where So-
nopet and CUSA are being used and to pre-
vent the accumulation or adhesions of bone
dust and other debris to the surrounding
• For tamponade and hemostatic effects
• To use as soft and atraumatic dissection
masses such as in the development of the
plane between tumor and surrounding tissue.
• To gently dissect small vessels from sur-
rounding neural tissue.
• To prevent the wall of a cavity to collapse
during surgery of large tumors, while provid-
ing some tamponade effect against small
venous oozing
• To take care of small venous oozing during
dissection of e.g. Sylvian fissure
• To use as small expansive masses that can
be used to keep a dissected fissure open
during e.g. MCA aneurysm surgery, or during
an interhemispheric approach
• To keep a temporary clip aside or to orient
the aneurysm dome into the better position
during final clipping
The cottonoids should not be placed close to
an area where a high speed drill is being used
as they very often get swept away by the drill
and while rotating can cause damage to the
surrounding tissues.
4.9.9. Sharp and blunt dissection
Sharp dissection means cutting across tissue
planes, and blunt dissesction going between
tissue planes and anatomical boundaries. The
use of the microscissors to cut appropriate
arachnoid membranes or adhesions is a classic
example of sharp dissection. But an arachnoid
membrane can be also opened by punctur-
ing it with sharp bipolar forceps, cutting the
membrane with a special arachnoid knife, or by
tearing the arachnoid membrane using short
jewelers' forceps. A cheap alternative to the
arachnoid knife is a disposable, sharp, straight
needle attached to a 1 ml syringe acting as a
handle. Blunt dissection is usually performed by
entering a natural cleavage plane, and follow-
ing this plane while stretching the plane fur-
ther on. The common methods in our practice
are the use of bipolar forceps, microdissector,
small cottonoids, and most importantly the use
of water dissection (see below).
4.9.10. Irrigation and water dissection
Irrigation is used very liberally and in large
amounts throughout the whole operation. Its
main uses are: (a) keeping the operation field
clean, (b) identifying bleedings, (c) preventing
tissues from drying and sticking to the instru-
ments, and (d) water dissection. For irrigation
warm physiologic saline is used. It is applied
from a normal, hand-held 20 ml syringe with a
straight, blunt needle with a rather large bore.
Perhaps the most popular and distinctive
method of dissection seen in Helsinki is the
use of water dissection. This was described and
popularized by Dr. Toth in Budapest and is not
as recognized as it probably should be. It is ef-
fective, least hazardous and cheap! Water dis-
section is used to separate natural planes from
each other. First the origin of the dissection
plane is identified. Then saline is injected using

104
4 | Closing
a handheld syringe into the cleavage plane that
stretches and expands facilitating further iden-
tification of planes, structures and further sharp
dissection. The same technique can be used to
expand any kind of borders or plains, e.g. when
dissecting an extra-axial tumor, opening the
Sylvian fissure or removing an AVM.
4.9.11. Minimal retraction
In Helsinki style microneurosurgery, where it
is possible, no brain retractors are used. There
are some exceptions where a narrow tipped
Sugita retractor is used such as some ACoA
aneurysms or when removing a deep-seated
lesion such as e.g. intraventricular meningioma
or third ventricle colloid cyst. Then there are
certain approaches, such as the subtemporal
approach toward a basilar tip aneurysm, which
simply cannot be performed without a wide
self-retaining retractor, even if a lumbar drain
has been used to remove CSF.
Instead, it is primarily the use of the appropriate
suctiontipshaftandbipolarbladestogetherwith
cottonoids that provide gentle retraction of the
brain but mostly they maintain surgical space
already gained, e.g. in the subfrontal dissection
for a cerebral aneurysm or to open the lamina
terminalis. At first, the bipolar forceps is used
for retracting for the suction to release CSF and
then the suction is used to maintain that space
while bipolar forceps are working. This maneu-
ver is important to understand and is probably
best grasped by watching the videos, especially
the opening of the lamina terminalis. In expe-
rienced hands the role of microretractors by
the suction or bipolar forceps are constantly
and subconsciously interchanged. This allows
the surgeon to almost crawl in along natural
planes, e.g. in subfrontal dissection.
4.10. CLOSING
In Helsinki, closing of the wound, including
the skin, is performed under the magnification
of the operating microscope. This is an excel-
lent way of microsurgical training. At the same
time, due to magnification and good illumina-
tion, hemostasis can be achieved easier under
visual control. One should always be confident
on how to bail out, so knowing how to close
well is necessary before advancing to any more
complex procedures.
Closing is performed in layers. Dura is closed
watertight if possible with running 3-0 or 4-0
suture using atraumatic needle. Small dural
defects are sealed with fibrin glue. For large
dural defects we use either pedicled periostium
flap or some commercial dural graft, several of
which are widely available from different com-
panies. Tack-up sutures between the dura and
the previously drilled holes at the craniotomy
edge are used to stop oozing from the epidural
space and Surgicel packing further enhances
this effect. Dura is overlayed with some Surgicel
before putting the bone back. The bone is fixed
with two or more Aesculap Craniofixes. Only in
large bone flaps one or several central sutures
are used. Muscle is closed in one or several lay-
ers with resorbable 2-0 running or interrupted
sutures. The fascia of the muscle should be
continous if possible. The next layer, the galea-
subcutaneous layer, is closed again with either
running or interrupted 3-0 resorbable sutures.
Care is needed to have the two wound edges
at the same level for optimal cosmetic result.
Staples are used for the skin and removed after
five to seven days. We do not use any drains,
instead rather rely on meticulous hemostasis.
The only exceptions for use of drains are very
large hemicraniectomies or cranioplasties in
trauma or brain infarction patients.

105
Key factors in Helsinki style microneurosurgery | 4
4.11. KEY FACTORS IN HELSINKI STYLE
MICRONEUROSURGERY
The key factors and ingredients of Helsinki
style microneurosurgery that make surgeries
smoother and faster are the following:
• Consistency in preparation. A sound and
safe method, including checks and proce-
dures, which have been based on good clinical
reasons and principles. The habits contain
steps and checks that avoid problems. Have
consistency in the operation at all its stages.
Everyone who is involved in the operation
should know what you want, need and what
to expect.
• Fast surgery because it is better than slow. It
does not mean hurry! If there is one move
that will compensate for two, go for it. Be
efficient.
• Continuous training. To achieve speed and
flare in microneurosurgery one needs a lot of
training.
• Calmness and contemplation, yet ability to
adapt for action and what the situation
demands.
• Respect for the teamwork. Being kind,
understanding, pleasant and respectful to all
the staff and team, yet firm and uncompro-
mising in standards for patients.
• Working hard. There is no substitute for
working hard with dedication.
More subtle and specific features of the opera-
tive techniques and style of Prof. Hernesniemi
are the following:
• The interchange of function between left
and right hand instruments. Both hands work
towards the same goal. At all times the
movements are perfectly weighted and as
atraumatic as possible. This allows fast and
smooth procedures such as the opening of
the lamina terminalis when there is an angry
swollen brain.
• Minimal use of traumatic fixed retraction
systems. It is much safer to use high magni-
fication on the microscope and make gentle
use of mainly the left hand instrument as a
retractor.
• Maximum and efficient use of the best few
microinstruments. "Hand signs" for these
common instruments allow the scrub nurse
to anticipate the next move. Special instru-
ments should be available as well but their
use is limited and brief.
• The use of the blind change of instruments
with the right hand and the use of the steady
pivotal left hand when needing to look away
from the microscope. This avoids the loss of
the left hand retractor function, as well as
loss of the surgical planes and space that
have been gained during earlier dissection.
In addition this avoids the repetitive with-
drawing and re-inserting of the left hand
instrument into the surgical field.
• Avoidance of unnecessary gaps, pauses and
delays. Break can be taken when it is safe to
do so. But the general action stays focused
on the goal and each movement brings this
goal closer.
• Teamwork together with the scrub nurse. The
scrub nurse should know when, what and
why something is needed. This is why it pays
off to be consistent and keep things fast,
safe and simple!
• Uncompromised approach towards the
requirements for successful surgery. Careful
planning and pre-emptive evasion of prob-
lems result in smooth execution of the
surgery.
• A soft, neutral music in the OR helps to relax
the team.

106
4 | List of Prof. Hernesniemi´s general habits and instruments
4.12. LIST OF PROF. HERNESNIEMI'S GENERAL
HABITS AND INSTRUMENTS
The habits of Professor Hernesniemi as record-
ed by the nursing staff. This list is updated on
regular basis and is used both as memoran-
dum as well as training material for new scrub
nurses.
• Always standing troughout operation
(except bypass surgery)
• Sugita head fixation clamp and always
screws for adults, even for children
• Before covering operating area he puts
abdominal swabs and a big Opsite film
around the operating area
• Size L operating theatre gown,
made of microfiber
• Arm rest stand
• Mayo-stand cover for arm rest stand
• Medena suction tube (Astra Tech)
• Scalpel blade for skin (e.g. Aesculap BB523)
• Scalpel blade for opening the dura
(e.g. Aesculap BB515)
• Cottonoids without thread
• Surgicel fibrillar
• Bone wax Aesculap (e.g. Aesculap 1029754)
• Cranial perforator (e.g. Aesculap GB302R)
• As a wirepass drill, he uses craniotomy drill
bit without foot plate
• Fibrin glue (e.g. B. Braun Tisseel Duo Quick)
should always be ready with straight tip
• Diathermy setting 50, bipolar 50 in the
beginning, after dura has been opened 30,
for aneurysms 25, with sharp bipolar tip 20
• Around the opening small wet hydrogen-
peroxide swabs and a green cloth fixed with
wound staples
• In the beginning, a short suction cannulae
#12 (e.g. Aesculap GF409R);
after craniotomy #8 suction cannulae
(e.g. Aesculap GF406R); length depending
on the depth (three different lengths)
• Papaverin solution ready for every aneurysm
surgery & vascularized tumors
• Tack-up sutures: Safil violet 3/0 hrt26
(e.g. Aesculap C1048742)
• Dural sutures: Safil violet 4/0 hrt22
(e.g. Aesculap C1048329)
• In spinal surgery, tack-up sutures 4-0 Prolene
• Irrigation tip is re-useable blunt steel needle
• "Needle-knife" = 1ml syringe + 18 g pink
hypodermic needle
• AVM's and caroticocavernous fistulae
-> lots of fibrin glue
(e.g. B. Braun Tisseel Duo Quick)
• In every re-craniotomy, free boneflap is
soaked in antibiotic solution (cloxacillin),
after which boneflap is soaked in saline
before re-attachment
• To lift up tentorium in subtemporal
approach – YASARGIL MINI temporary
Aneurysm Clip (e.g. Aesculap FT210T)
• Small openings: use of a small DIADUST
micro needle holder (e.g. Aesculap BM302R)
and MICRO-ADSON tissue forceps
(e.g. Aesculap BD510R) or bayonet micro
forceps (e.g. Aesculap FD111R, BD836R)
• Long narrow DIADUST micro needle holder
(e.g. Aesculap BM327R)
• For thin ventricular catheter a barium
integrated catheter + green IV cannula
• "Childrens glue" = e.g. B. Braun Histoacryl
(for example to wrap an aneurysm)
• For drilling in spinal surgery only long drill
tips, not extended drill tips

107
List of Prof. Hernesniemi´s general habits and instruments | 4
• 2/0 Safil take-off sutures for muscle and
subcuticular sutures (e.g. Aesculap
C1048031), skin closed with wound staples
• CranioFix2 clamp, 11 mm, FF490T x 3
Craniotomy & instruments
• High speed power system
(e.g. Aesculap HiLAN XS drill system)
• Hi-Line XS Rosen burr
(D5.0mm e.g. Aesculap GE408R,
D6.0mm e.g. Aesculap GE409R)
• Hi-Line XS Diamond burr
(D5.0mm e.g. Aesculap GE418R,
D6.0mm e.g. Aesculap GE419R)
• Cranial Perforater Hudson D6/9mm
(e.g. Aesculap GB302R)
Professor's standard microinstruments
• Bipolar forceps
 CASPAR Coagulation Forceps
“ice-hockey”
(e.g. Aesculap GK972R, GK974R)
 CASPAR Coagulation Forceps 19.5 cm
regular (e.g. Aesculap GK940R)
blunt (e.g. Aesculap GK900R)
sharp x 2 (e.g. Aesculap GK899R)
sharp x 2 (e.g. Aesculap GK929R)
• Suction cannulaes
 Length L, 5 Fr (e.g. Aesculap GF413R)
 Length L, 7 Fr. (e.g. Aesculap GF415R)
 Length M, 6 Fr. (e.g. Aesculap GF394R)
 Length S, 8 Fr. (e.g. Aesculap GF406R)
 Length S, 12 Fr. (e.g. Aesculap GF409R)
• Irrigation tip, metal blunt
 short
 8 cm
• HALSTED-MOSQUITO Haemostatic forceps
(e.g. Aesculap BH111R)
• Brain Spatulas (e.g. Aesculap FF222R)
• Clip Appliers
 YASARGIL MINI Clip Applier
(e.g. Aesculap FT474T)
 YASARGIL Titanium Clip Applier standard

108
• Microscissors
 Micro dissecting scissors
(e.g. Aesculap FD103R)
 Micro scissors 12-17329
 YASARGIL micro scissors straight
 YASARGIL micro scissors angled
 Kamiyama scissors
• Micro Dissectors / Micro Hooks
 Micro dissector 200 mm, 8”
(e.g. Aesculap FF310R)
 Sharp hook 90° angled, 185mm, 7 ¼”
 Nerve- and Vessel Hook
• Microforceps
 Ring Forceps for Grasping Tissue, Tumors
etc. (e.g. Aesculap BD766R)
 Ring Forceps for Grasping Tissue, Tumors
etc. (e.g. Aesculap BD768R)
 Micro Forceps, short x 2
(e.g. Aesculap BD330R)
 Forceps with teeth
(e.g. Aesculap BD886R)
Occipital surgery
• If opening in the midline, patient is in sitting
position – very old patients and children are
operated in prone position (emergency cases
may be operated in prone position because
OR technician is not present)
• If opening is lateral suboccipital, patient is in
park bench position and surgeon is on either
side & nurse is standing at the cranial end
• Sometimes a spinal drainage is used
• Curved self-retaining Retractors Aesculap
BV088R (Mastoid retractor) are used instead
of Raney clips (e.g. Aesculap FF015P) and
Sugita frame fish hooks
• Craniotomy instruments
(e.g. Aesculap HiLAN XS drill system)
• Small cotton buns on Kocher clamp
(e.g. Aesculap BF444R)
• Vicryl take-off sutures in the lower muscular
layer for closure
May need:
• Nicola Tumor clamp (e.g. Aesculap OF442R)
• Kerrison bone punch, noir, detachable,
2mm (e.g. Aesculap FK907B)
• Micro Scissors curved right
• Long DIADUST micro needle holder
(e.g. Aesculap BM327R)
• His own long micro instruments
• Long suction cannulae
(e.g. Aesculap GF413R, GF415R)
• Long irrigation tips
• “Black Rudolf” tumor clamp 23 - 01049
• Large long ring forceps
4 | List of Prof. Hernesniemi´s general habits and instruments

109
List of Prof. Hernesniemi´s general habits and instruments | 4
• Small long ring forceps
• Long micro hook, semi-sharp, 23 cm
• Long micro hook, blunt, 23 cm
• YASARGIL Coagulation Forceps 21.5 cm
(e.g. Aesculap GK775R)
• YASARGIL Coagulation Forceps 23.5 cm
(e.g. Aesculap GK791R)
• YASARGIL Micro Scissors straight
• YASARGIL Micro Scissors curved
Aneurysm surgery
• YASARGIL MINI Aneurysm Clips
(e.g. Aesculap FT690T, FT720T etc.)
• YASARGIL STANDARD Aneurysm Clips
• Papaverin
• Double Bayonet Clip Applier without latch
(e.g. Aesculap FT515T, FT516T)
May need:
• Second suction
• YASARGIL Titanium Fenestrated Clips
• Might lift tentorium with a YASARGIL MINI
temporary Aneurysm Clip
• Histoacryl Blue (B.Braun1050044)
“childens glue” for wrap-ping
• If aneurysm cannot be fully clipped
-> 7-0 or 8-0 suture and micro needleholders
(e.g. Aesculap FD245R, FD247R, FD092R,
FD093R, FD120R)
• MCA aneurysms -> YASARGIL STANDARD
Clip Applier (e.g. Aesculap FT480T, FT470T)
AVM surgery
• Equipment like in aneurysm surgery
• Kopitnik AVM Microclip
(e.g. Aesculap FE902K, FE914K etc.)
• AVM Clip Applier
(e.g. Aesculap FE917K, FE918K)
• Bypass micro instruments
• Lots of fibrin glue
(e.g. B. Braun Tisseel Duo Quick)

111
Lateral supraorbital approach approach | 5
5. COMMON APPROACHES
Each of the described approaches is also
demonstrated on supplementary videos,
please see Appendix 2.
5.1. LATERAL SUPRAORBITAL APPROACH
The most common craniotomy approach used
in Helsinki by Prof. Hernesniemi is certainly the
lateral supraorbital (LSO) craniotomy. The LSO
has been used in more than 4,000 operations
to access vascular pathologies of the anterior
circle of Willis as well as extrinsic and intrin-
sic tumors of the anterior fossa and basal re-
gions of the frontal lobes. The LSO approach
is a more subfrontal, less invasive, simpler and
faster modification of the classical pterional
approach by Yaşargil. The LSO utilizes smaller
incision, it dispenses with the laborious sub-
facial dissection and involves taking a smaller
free bone flap which has less temporal exten-
sion than the pterional bone flap.
In the LSO approach the skin-muscle flap is
opened as a one layer block and only the an-
terior portion of the temporal muscle is split
open. The partial split of the temporalis muscle
has ensured very little risk of problems with
the temporomandibular joint, mastication and
mouth opening, and late disfiguring muscle at-
rophy. The facial branch to the frontalis muscle
is not damaged as it is not exposed, dissected
or cut during the craniotomy. Due to relatively
short skin incision and a small bone flap the
closure is also simpler. The Finnish people have
generally thin and light eyebrows. This pre-
cludes the possibility of using an eye-brow
incision.
5.1.1. Indications
The LSO approach can be used to access all
aneurysms of the anterior circulation, except
those of the distal anterior cerebral artery.
The LSO approach can be used also for high
positioned basilar bifurcation or even basilar-
SCA aneurysms. In addition to aneurysms,
LSO approach can be used for most patholo-
gies involving the sellar and suprasellar region,
and tumors of the anterior cranial fossa and
sphenoid ridge. The LSO approach is our pre-
ferred route to enter the Sylvian fissure and
the pathologies that can be accessed through
there. It gives excellent access to the anterior
portion of the Sylvian fissure and by extending
the craniotomy more in the posterior and tem-
poral direction also the distal part of the Syl-
vian fissure can be visualized. By adjusting the
exact location of the LSO craniotomy, one can
achieve either a more frontal or a more tempo-
ral exposure. This combined with well-planned
head positioning provides usually an excellent
accesses to nearly all of the above mentioned
pathologies with ease.

112
5.1.2. Positioning
The patient is positioned supine with shoul-
ders and head elevated above the cardiac level.
The head, fixed with 3 or 4 pins to the head
frame is: (a) elevated clearly above the cardiac
level; (b) rotated 15 to 30 degrees toward the
opposite side; (c) tilted somewhat laterally;
and (d) extended or minimally flexed (Figure
5-1a,b). We prefer to use a Sugita head frame
with 4-point fixation. Besides providing good
retraction force by its spring hooks, it allows
the surgeon to rotate the head during micro-
surgery. If this feature is not available, the
table can be rotated as needed. The head ori-
entation is to allow for a comfortable working
angle, downward and somewhat forward. Nev-
ertheless, the position of the head and body is
subject to frequent changes as necessary dur-
ing the whole operation. The exact positioning
of the head depends on the pathology being
approached and is adjusted on case-by-case
basis. One has to imagine the exact location
and orientation of the lesion in 3D space to
plan the optimal head position. In general, the
head is rotated less to the opposite side than
in standard pterional approach. If the head is
rotated too much, the temporal lobe obstructs
easy access into the Sylvian fissure. The exten-
sion of the head depends on the cranio-caudal
distance of the pathology from the base of the
anterior cranial fossa. The higher the lesion is,
the more the head needs to be extended. The
upper limit of the access is 15 mm from the
anterior skull base in the chiasmatic region.
On the other hand, for lesions near the skull
base little flexion might be needed. Lateral tilt
is used to orientate the proximal part of the
Sylvian fissure almost vertical, which helps in
exposing the proximal middle cerebral artery
and the internal carotid artery.
5 | Lateral supraorbital approach approach
Figure 5-1 (a). Lateral supraorbital approach. See text for details

113
Figure 5-1 (b). Lateral supraorbital approach. See text fordetails
5.1.3. Incision and craniotomy
The shaved area is minimal. An oblique fron-
totemporal skin incision is made behind the
hairline (Figure 5-1a,b). The incision stops 2 to
3 cm above the zygoma and is partially opened
by frontal spring hooks. Raney clips are placed
on the posterior margin of the incision (Figure
5-1c). The temporal muscle is split vertically by
a short incision, and one spring hook is placed
in the incision to retract the muscle towards
the zygomatic arch. The one-layer skin-muscle
flap is retracted frontally by spring hooks until
the superior orbital rim and the anterior zygo-
matic arch are exposed (arrow; Figure 5-1d).
The extent of the craniotomy depends on the
surgeon's experience and preferences. Usually
a small LSO craniotomy is enough (the keyhole
principle).
A single burr hole is placed just under the tem-
poral line in the bone, the superior insertion
of the temporal muscle (Figure 5-1e). The dura
is detached from the bone with a curved dis-
sector "Jone" (Figure 4-11a - page 92). Each
side of the instrument has a stout, curved,
blunt end that makes it an ideal instrument
for this function. The bone flap of 5 x 3 cm is
detached mostly by the side-cutting drill. First
a curved cut is made from the burr hole to-
wards the region of the zygomatic process of
the frontal bone. Then an almost straight sec-
ond cut is made from the burr hole towards
the temporal bone. The sphenoid ridge is left
in between these two cuts (Figure 5-1f). Fi-
nally, the two cuts are joined by thinning the
bone along a straight line with the craniotome
blade without the footplate. The bone is then
cracked along this line by using a stout dis-
sector and leverage from the burr hole region
and the bone flap is lifted (Figure 5-1g). Before
cracking the bone, a few drill holes are made

114
C
D
Figure 5-1 (c - d). Lateral supraorbital approach. See text for details

115
E
F
Figure 5-1 (e - f). Lateral supraorbital approach. See text for details

116
G
H
Figure 5-1 (g - h). Lateral supraorbital approach. See text for details

117
Figure 5-1 (i). Lateral supraorbital approach. See text for details
I
for tack-up sutures. The lateral sphenoid ridge
is then drilled off allowing access to the skull
base (arrows; Figure 5-1h). The drilling starts
with a high-speed drill and continues with a
diamond drill. Oozing of blood from the bone
is finally controlled by "hot drilling", i.e. using a
diamond tipped drill without irrigation heating
the bone and sealing the bleedings. The wound
is irrigated, and hemostasis is achieved using
bipolar, Surgicel and cottonoids.
The dura is opened using a curvilinear incision
pointing anterolaterally (dotted line; Figure
5-1h), the dural edges are elevated by multiple
stitches, extended over craniotomy dressings
(Figure 5-1i). This prevents oozing from the
epidural space. From this point on, all surgery
is performed under the operating microscope,
including the skin closure.
The first goal during intradural dissection is
usually to reach basal cisterns for CSF release
and brain relaxation. The dissection starts
along the frontobasal surface of the frontal
lobe slightly medially from the proximal Syl-
vian fissure. The first aim is to reach the optic
nerve and its entrance into the optic canal. The
arachnoid membranes limiting the optic cis-
tern are opened and CSF is released. For further
CSF release also the carotid cistern on the lat-
eral side of the optic nerve is entered. With the
brain relaxed the dissection continues accord-
ing to the pathology. In situations with very
tight brain and little CSF in the basal cisterns,
as e.g. in acute SAH, we try to remove more CSF
by opening the lamina terminalis. To reach the
lamina terminalis, we continue with the dis-
section subfrontally, along the ipsilateral optic
nerve towards the optic chiasm. This dissection
step is often complicated by lack of space and
requires high magnification. The frontal lobe
can be gently retracted by tandem work of bi-
polar forceps and suction to reach the gray-
bluish membrane of the lamina terminalis just
posterior to the optic chiasm. The translucent
membrane is punctured with sharp bipolar for-
ceps or closed microscissors and further CSF is
released directly from the third ventricle. The
dissection then continues as planned.
T&T:
• Accurate head positioning, imagine in 3D
how the lesion is situated inside the head
• Short incision centered on the orbitocranial
joint
• One layer skin-muscle flap, one hook
retracts incised muscle downward
• One burr hole at the temporal line
• Bone removed basally to minimize retrac-
tion, diamond drill stops bleeding from bone
• Brain is relaxed by releasing CSF from
basal cisterns and further through lamina
terminalis

118
5.2. PTERIONAL APPROACH
The pterional approach we have adopted is a
slight modification of the classical pterional
approach as described by Yaşargil. The biggest
differences are: (a) the skin incision is slightly
different, it starts closer to the midline; (b) we
use a one-layer skin-muscle flap instead of
several layers; (c) only one burr hole is used at
the superior insertion of the temporal muscle;
and (d) we do not remove bone all the way
down to the anterior clinoid process or perform
extradural anterior clinoidectomy routinely.
5.2.1. Indications
Most of the lesions for which pterional ap-
proach has been classically used, are treated in
our hands using the LSO approach. The pteri-
onal approach is reserved only for those situa-
tions where wider exposure of both the frontal
and temporal lobes as well as the insula is nec-
essary and where we anticipate lack of space
during the surgery. Such situations are giant
anterior circulation aneurysms, especially MCA
aneurysms, AVMs close to the Sylvian fissure or
insular tumors.
5 | Pterional approach
Figure 5-2 (a). Pterional approach. See text for details.

119
Pterional approach | 5
Figure 5-2 (b). Pterional approach. See text for details.
5.2.2. Positioning
The positioning for the pterional approach is
almost identical to that for the LSO approach
(see section 5.1.2.) (Figure 5-2a,b). The angle
of approach is the same, the only difference is
that pterional approach provides a wider bony
window.
The head is shaved about 2 cm along the hair-
line. The skin incision is planned to start just
behind the hairline at the midline. It then ex-
tends in a slightly oblique fashion and termi-
nates in front of the ear, close to the level of
zygoma (Figure 5-2a,b). Compared to the LSO
approach the skin incision is: (a) longer; (b)
curves little more posterior; and (c) extends
several centimeters closer to the zygoma.
The opening is carried out in a single layer like
in the LSO approach. The temporal muscle is
split along the muscle fibers and spring hooks
are placed to retract the skin-muscle flap in
the fronto-basal direction (Figure 5-2c). Raney
clips are used along the posterior wound edge.
The temporal muscle is detached from the
bone with diathermia. The retraction of the
hooks is increased so that, finally, the superior
orbital rim and the anterior zygomatic arch
are exposed (arrow; Figure 5-2c). A groove in
the bone marks the expected location of the
Sylvian fissure and the borderline in between
the frontal and the temporal lobes (blue dotted
line; Figure 5-2c).
A single burr hole is placed just beneath the
temporal line (Figure 5-2d). The dura is care-
fully detached first with a curved dissector and

120
C
D
Figure 5-2 (c - d). Pterional approach. See text for details.

121
E
F
Figure 5-2 (e - f). Pterional approach. See text for details.

122
then with a flexible (Yaşargil-type) dissector
(Figure 4-11b - page 92). Since the bone flap is
going to be larger than in the LSO approach, the
dura needs to be detached more extensively es-
pecially in the temporal direction. Two cuts are
made with a craniotome. The first one curves
medially and frontobasally and terminates at
the sphenoid ridge just after passing the origin
of the anterior zygomatic arch. The other cut
is directed in the temporal direction almost in
a straight line and then curves slightly in the
temporobasal direction, towards the zygoma
(Figure 5-2e). Finally, the bone is thinned ba-
sally over the sphenoid ridge, connecting the
two cuts. This is done with the craniotome
without the footplate. The bone is cracked and
lifted. Before cracking the bone, few drill holes
are made for tack-up sutures. Once the bone
flap has been removed, the dura is detached
further in the basal direction on both sides of
the sphenoid ridge. The sphenoid ridge is then
drilled away with a high-speed drill (arrows;
Figure 5-2f). Hot drilling with a diamond drill
bit is used to seal the small bleedings from the
bone. We do not remove the anterior clinoid
process.
The dura is opened in a curvilinear fashion with
the base in the fronto-basal direction (Figure
5-2f). The dural edges are elevated over the
craniotomy dressings with tight lift-up sutures
to prevent oozing from the epidural space (Fig-
ure 5-2g). Compared to the LSO approach, we
see now more of the temporal lobe and the
craniotomy extends also little further posterior.
Under the microscope, the first aim is to relax
the brain by removing CSF from the basal cis-
terns and if necessary, from the third ventricle
through the lamina terminalis as with the LSO
approach. The dissection then proceeds accord-
ing to the pathology in question, often involv-
ing opening of the Sylvian fissure (see section
6.1.6.).
Figure 5-2 (g). Pterional approach. See text for details.
G

123
The closure is performed in the standard layer-
like fashion in the similar way as for the LSO
approach.
T&T:
• Head positioning according to the
pathology
• Skin incision behind the hairline
• Skin and muscle detached in one layer
• Only one burr hole necessary
• Dura carefully detached before using the
craniotome
• Sphenoid ridge removed with high speed
drill, and hot drilling
• No need for routine anterior clinoidectomy

124
5.3. INTERHEMISPHERIC APPROACH
The interhemispheric approach is used to gain
access into the space in between the two hem-
ispheres in the midline on either side of the
falx and, if necessary, through the transcallosal
route also into the lateral ventricles and the
third ventricle. The important aspect regarding
the interhemispheric approach is the absence
of good anatomical landmarks once inside the
intehemispheric space. The falx and the plane
between the cingulate gyri mark the midline
but estimating the antero-posterior direction
is very difficult and one might get easily lost.
It is necessary to know the exact head orienta-
tion and to check the angle of the microscope
to estimate the appropriate angle of approach.
The neuronavigator can be helpful in planning
the trajectory.
5.3.1. Indications
The most common lesions to be operated via
interhemispheric route are distal anterior cer-
ebral artery aneurysms and third ventricle col-
loid cysts. In addition certain rare pathologies
such as very high located craniopharyngiomas
or other pathologies of the third ventricle and
those of the lateral ventricles can be accessed
via this route as well. Parasagittal or falx men-
ingiomas are also approached in this way but
the craniotomy usually needs to be more ex-
tensive, dural incision and possible removal
must be planned in advance. In addition, possi-
ble tumor infiltration into the superior sagittal
sinus plays a major role.
5 | Interhemispheric approach
Figure 5-3 (a). Interhemispheric approach. See text for details.

125
Interhemispheric approach | 5
5.3.2. Positioning
For the anterior interhemispheric approach the
patient is placed in supine position, a stiff pil-
low beneath the shoulders, with the head fixed
in a head frame and elevated about 20º above
the heart level. The head should be in neutral
position with the nose pointing exactly up-
wards (Figure 5-3a,b). Tilting the head to either
side increases the risk of placing the bone flap
lateral from the midline. This would make both
entering into the interhemispheric fissure as
well as navigating inside it more difficult. The
head is slightly flexed or extended according
to the exact location of the pathology (Figure
5-3a). In the optimal position the surgical tra-
jectory is almost vertical.
After minimal shaving, a slightly curved skin
incision with its base frontally is made just
behind the hairline, over the midline (arrow;
Figure 5-3b), extending more to the side of
the planned bone flap. This incision is used
for most pericallosal aneurysms, and third
ventricle colloid cysts. For approaches behind
the coronal suture a straight incision along
the midline is used. Exact location, curvature,
and extent of the skin incision depends on the
hairline, dimensions of the frontal sinuses, and
location of the pathology. A one-layer skin flap
is reflected frontally with spring hooks (Figure
5-3c). A bicoronal skin incision is unnecessary
since strong retraction with hooks often allows
for an anterior enough exposure of the frontal
bone.
Figure 5-3 (b). Interhemispheric approach. See text for details.
B

126
Figure 5-3 (c). Interhemispheric approach. See text for details.

127
The bone flap is placed slightly over the midline
to allow better retraction of the falx medially.
The superior sagittal sinus may deviate laterally
from the sagittal suture as far as 11 mm. The
size of the bone flap depends both on the sur-
geon's experience and on the size of the lesion.
We usually use a 3 to 4 cm diameter flap. Too
small a flap may not provide sufficient space
for working between the bridging veins. In
most patients, only one burr hole in the midline
over the superior sagittal sinus at the posterior
border of the bone flap is needed (Figure 5-3d).
Through this hole, the bone can be detached
from the underlying dura. One has to be care-
ful with the underlying superior sagittal sinus,
particularly in the elderly with a very adherent
dura. With modern trephines we have not ex-
perienced any accidental tears in the sagittal
sinus. The bone flap is removed using a side-
cutting drill (Figure 5-3e). High-speed drill can
be used to smoothen the edges or to enlarge
the opening if necessary. If the frontal sinuses
are accidentally opened during the craniotomy,
they should be stripped of endonasal mucosa,
packed and isolated with fat or muscle grafts
and covered with pericranium.
The dura is opened under the operating micro-
scope as a C-shaped flap with its base at the
midline (Figure 5-3f). The incision is first made
in the lateral region and then extended to-
wards the midline in the anterior and the pos-
terior direction to prevent opening of the supe-
rior sagittal sinus. The dural opening should be
planned so that possible meningeal sinuses and
venous lacunae are left intact. Bridging veins
may be attached to the dura for several cen-
timeters along the midline. Careful dissection
and mobilization of these veins is necessary. It
is usually during the opening of the dura that
accidental damage to the bridging veins takes
place. Dural edges are elevated with multiple
stitches extended over the craniotomy dress-
ings to prevent epidural oozing into the surgi-
cal field (Figure 5-3g).
If the neuronavigation system is used, the cor-
rect angle of the trajectory should be verified
while planning the skin incision. With the bone
flap removed and the dura still intact, the ap-
proach trajectory has to be checked again for
correct working angle of the microscope. After
the dura has been opened and CSF released,
brain shift will make neuronavigation less reli-
able, and one becomes more dependent on vis-
ible anatomic landmarks.
T&T:
• The is head elevated, flexed or extended as
needed, but no rotation or lateral tilt
• Check the head position and microscope
angle before draping
• The neuronavigator is helpful in planning
the optimal trajectory
• Curved incision frontally for anterior
lesions, straight incision on midline for
parietal and occipital lesions
• One burr hole in the midline over the
sagittal sinus
• Do not sacrifice bridging veins, flap large
enough to go on either side of an
important vein
• Craniotomy should extend slightly over
the midline to allow some retraction of
the sagittal sinus
• Corpus callosum identified by white color,
striae longitudinales and transverse fibres
• Pericallosal arteries run usually along the
corpus callosum, but can be on either side
of the falx

128
Figure 5-3 (d). Interhemispheric approach. See text for details.

129
Figure 5-3 (e). Interhemispheric approach. See text for details.

130
Figure 5-3 (f). Interhemispheric approach. See text for details.

131
Figure 5-3 (g). Interhemispheric approach. See text for details.

132
5 | Subtemporal approach
Figure 5-4 (a). Subtemporal approach. See text for details.
5.4. SUBTEMPORAL APPROACH
The subtemporal approach is used mainly
to access the basilar tip: basilar bifurcation,
basilar-superior cerebellar artery (SCA) and
posterior cerebral artery aneurysms (PCA). It
gives good visualization of the interpeduncular
space and also the floor of the middle fossa.
Also P1 and part of the P2 segment of the PCA
can be visualized with subtemporal approach.
Subtemporal approach is an excellent example
of how a relatively simple and fast approach
without extensive bony work can be used to
access similar structures as with much more
complex skull base approaches.
5.4.1. Indications
Most basilar tip aneurysms located below the
posterior clinoid process and those at the pos-
terior clinoid or less than 10 mm above the
posterior clinoid process are treated by using
the subtemporal approach. This approach has
been used by Prof. Hernesniemi since 1980s
and was refined during his training period with
Profs. Drake and Peerless in 1989 and 1992-
1993. They used the subtemporal approach
in 80% of 1234 basilar tip aneurysm patients
treated between 1959 and 1992. Advantage of
the subtemporal approach is that it provides a
lateral view on the basilar artery and provides
better visualization of the perforators originat-
ing form the basilar tip. These perforators are
usually hidden by the bifurcation if accessed
through the trans-Sylvian route.

133
Subtemporal approach | 5
5.4.2. Positioning
The patient is placed in park bench position
with the head fixed in the Sugita frame and:
(1) elevated above the cardiac level; (2) upper
shoulder retracted; and (3) the head tilted lat-
erally towards the floor, without compromising
the venous outflow from the internal jugular
vein (Figure 5-4a). The right side is preferred
unless the projection or complexity of the
aneurysm, scarring from earlier operations, a
left oculomotor palsy, a left-sided blindness
or a right hemiparesis, requires a left-side ap-
proach. An important step is the protection of
the pressure points by use of pillows and pads
and resting the patient on a padded surface
on the lateral aspect of the rib cage, and not
only on their shoulder which can damage the
brachial plexus. The upper shoulder is retracted
away from the head caudally and slightly back-
ward with tape attached to operating table.
The tape should not be under too much ten-
sion not to cause traction injury to the brachial
plexus. The upper arm is rested on a pillow
and gently held in place. The underlying arm
is dropped over the cranial edge of the table,
supported in place by being partly wrapped in
the bed sheet and the sheet clamped in place
using towel clips (Figure 5-4b). Again all pres-
sure points are protected with pillows. Finally a
pillow is placed between the knees supporting
the lower limbs.
Spinal drainage or ventriculostomy are man-
datory for the subtemporal approach. Usually
a lumbar drain is inserted to ensure drainage
of sufficient amounts of CSF to facilitate mini-
mal retraction of the temporal lobe for access
towards the tentorial edge. This is imperative
and crucial for this approach. Even if CSF is
Figure 5-4 (b). Subtemporal approach. See text for details.

134
Figure 5-4 (c ). Subtemporal approach. See text for details.

135
gradually drained via suction during inspection
of the subtemporal region, it is unnecessarily
traumatic. Between 50 to 100 ml of CSF should
be removed prior to craniotomy.
5.4.3. Skin incision and craniotomy
This skin incision can be either linear or a
small horseshoe-like incision curving posteri-
orly (Figure 5-4c). The linear incision is placed
1 cm anterior to the tragus and starts just
above the zygomatic arch runs cranially 7 to
8 cm. The curved incision has the same start-
ing point but it curves posteriorly just above
the earlobe (Figure 5-4d). With the curved in-
cision, the craniotomy can be extended more
in the posterior direction, which eventually
leads to a wider exposure of the tentorium and
the interpeduncular fossa. Visualization of the
insertion of the fourth nerve into the tento-
rial edge will be easier and there will be more
room for dividing and lifting the tentorium. At
the same time approaching the tentorial edge
from slightly posterior direction requires less
temporal lobe elevation since the floor of the
middle fossa is not as steep here than closer
to the temporal pole. Posterior projecting basi-
lar bifurcation aneurysms and P1-P2 segment
aneurysms always require this wider approach.
The same applies for low-lying basilar bifurca-
tion aneurysms. Lately, we have been using the
curved incision in the majority of the cases.
A one-layer skin-muscle flap is turned with the
base caudally (Figure 5-4e). The Sugita frame
and spring hooks provide strong retraction in
the basal direction. The temporal muscle is
separated all the way down to the origin of the
zygomatic arch, which needs to be identified
and exposed. Cutting and removing the zygo-
matic arch to obtain even more retraction of
the temporal muscle is not necessary, strong
retraction with the spring hooks is enough.
While retracting the temporal muscle the ex-
ternal auditory canal should be left intact, re-
membering that the skin is usually thin in this
region.
One burr hole is placed at the cranial border of
the planned bone flap and a second burr hole
is made basally, close to the origin of the zy-
gomatic arch (Figure 5-4f). The reason for this
basal burr hole is dense attachment of dura
at this site. If only cranial burr hole is used,
the risk of dural tear is by far higher. A curved,
blunt dissector ("Jone") is used to carefully de-
tach the bone from the underlying dura. It is
very important to keep the dura intact so that
it can be later retracted basally to provide bet-
ter exposure in the subtemporal space. A 3 to
4 cm bone flap is detached with a craniotome.
The first cut is made anterior in between the
two burr holes, the second cut posterior from
the cranial burr hole all the way towards the
floor of the middle fossa (Figure 5-4g). Finally
the bone is thinned down along the basal bor-
der of the temporal bone in between the two
cuts and the bone flap is cracked. Holes for
tack-up sutures are drilled at the cranial bor-
der of the craniotomy. The craniotomy is then
widened basally by removing bone in the tem-
porobasal direction with high-speed drill (ar-
rows; Figure 5-4h). Large diamond drill can be
used for stopping bleedings using hot drilling.
The goal is to expose the origin of the floor of
the middle fossa so that there will be no ridges
obstructing the view when entering the sub-
temporal region. A common mistake is to leave
the craniotomy too cranial, which then requires
more retraction of the temporal lobe, causing
unnecessary injury. During drilling, very often
some of the air cells of the temporal bone are
opened (arrow; Figure 5-4i). This necessitates
meticulous closure at the end of the surgery
to prevent postoperative CSF leak. Sealing the

136
Figure 5-4 (d). Subtemporal approach. See text for details.

137
air cells with part of the temporal muscle flap
everted over the bony edge and sutured to dura
is one possible trick ("Chinese-Turkish trick").
Using fat graft, fibrin glue and bone wax are
other options.
If the spinal drain functions properly, the dura
should feel slack at this point. On the contrary,
if the dura is tense all the possible anesthe-
siological measures should be implemented to
decrease the intracranial pressure. The dura
is opened as a curved flap with the base cau-
dally and the dural edges are elevated over the
craniotomy dressings (Figure 5-4i,j).
The trick of the proper use of the subtemporal
approach lies in getting quickly, without heavy
compression of the temporal lobe, to the tento-
rial edge, where cisterns are opened to release
additional CSF and to relax the brain. The spinal
drain can be closed at this point. Elevation of
the temporal lobe should start close to the tem-
poral pole and the dissection proceeds posteri-
orly across the caudal surface, while taking
care not to stretch the bridging veins too much.
The retraction of the temporal lobe should be
gradually increased. Abrupt retraction or eleva-
tion of the middle portion of the temporal lobe
would risk tearing of the vein of Labbé leading
to temporal lobe swelling and venous infarc-
tion. Once the temporal lobe is mobilized and
elevated with the tentorial edge visible, a re-
tractor is placed to retain space for further ad-
vance towards the basilar bifurcation. We pre-
fer a relatively wide retractor to have a large
surface area without focal pressure points.
The elevation of the uncus with the retractor
exposes the opening to the interpeduncular
cistern and the third nerve. The third nerve can
be mobilized by cutting the arachnoid bands
surrounding it, but its palsy can easily occur
even after minimal manipulation. In other pa-
tients even prolonged manipulation of the third
nerve does not lead to any signs of postopera-
tive palsy. Even with the uncal retraction of the
third nerve, the opening into the interpeduncu-
lar cistern remains narrow. The opening can be
widened by placing a suture at the edge of the
tentorium in front of the insertion and the in-
tradural course of the fourth nerve lifting the
tentorial edge upwards. The original technique
of using a suture has been nowadays replaced
by a small Aesculap clip which is much easier
to apply through the narrow working channel.
If lifting the tentorium does not provide a wide
enough corridor, we partially divide the tento-
rium for better exposure. The cut, perpendicular
to the tentorial edge and about 10 mm long, is
performed posterior to the insertion of the IV
nerve, and the tentorial flap is fixed with a small
Aesculap clip(s) to get better exposure towards
the upper portion of the basilar artery. In cases
with a low-lying basilar bifurcation, dividing the
tentorium remains absolutely necessary, and a
more posterior approach with a larger bone flap
is planned from the beginning of the operation.
The posterior clinoid process does not have to
be removed when using the subtemporal ap-
proach to access low-lying basilar bifurcation.
T&T:
• Park bench position, always spinal
drainage (50–100 ml of CSF removed)
• Horseshoe incision preferred, allows more
posterior approach
• Gradual retraction of the temporal lobe
• Covering the temporal lobe with wide
rubber strips cut from surgical gloves
prevents cottonoids from sticking to the
cortex during retraction
• Wide retractor to hold the temporal lobe
• Occulomotor nerve is the highway to the
basilar tip, always passing between P1
and SCA
• Always use temporary clipping (or short
cardiac arrest with adenosine) of basilar
artery and possibly also PCom(s) for
smooth clipping of the aneurysm base

138
Figure 5-4 (e). Subtemporal approach. See text for details.

139
Figure 5-4 (f). Subtemporal approach. See text for details.

140
Figure 5-4 (g). Subtemporal approach. See text for details.

141
Figure 5-4 (h). Subtemporal approach. See text for details.

142
Figure 5-4 (i). Subtemporal approach. See text for details.

143
Figure 5-4 (j). Subtemporal approach. See text for details.

144
5 | Retrosigmoid approach
5.5. RETROSIGMOID APPROACH
The retrosigmoid approach provides good ac-
cess to the cerebellopontine angle. It is by
far simpler and faster with much less need
for bone removal than other more extensive
lateral posterior fossa approaches. The crani-
otomy is small and depending on how cranially
or caudally it is placed, different cranial nerves
and vascular structures can be accessed. The
retrosigmoid approach is classically used for
vestibular schwannoma surgery but with small
variations it can be equally well used for mi-
crovascular cranial nerve decompressions, an-
eurysms and skull base tumors of the lateral
posterior fossa. The main difficulty in the proper
execution of the retrosigmoid approach is cor-
rect patient positioning for an optimal surgical
trajectory into the steep posterior fossa, place-
ment of the craniotomy lateral enough so that
cerebellum is retracted as little as possible,
and good microanatomical knowledge of all
the structures in the posterior fossa, as there
is much less room for manipulation than in the
supratentorial space.
Figure 5-5 (a). Retrosigmoid approach. See text for details.

145
Retrosigmoid approach | 5
5.5.1. Indications
The most common use for retrosigmoid ap-
proach is in vestibular schwannoma surgery.
Other common pathologies include vertebral
artery – PICA aneurysms, microvascular cranial
nerve decompression of the V or VII nerve and
meningiomas of the lateral posterior fossa. In
general, the lesions that can be approached via
the small retrosigmoid "tic" craniotomy should
be located at least 10 mm cranially from the
foramen magnum. If located more caudally,
such as low-lying vertebral aneurysms, some
modification more towards the far lateral
approach is needed, with the craniotomy ex-
tended towards the foramen magnum and dis-
section of the extracranial vertebral artery. But
for lesions well above the foramen magnum a
straight incision with a small craniotomy is all
that is needed. Cranial to caudal location of
the bone flap depends on the exact location of
the lesion in question. The most cranial crani-
otomy, with its upper border above or at the
level of the transverse sinus, is usually made
for fifth nerve microvascular decompression.
Craniotomy for vestibular shwannomas is lo-
cated slightly little more caudally and the most
caudal craniotomies are typically for vertebral
aneurysms at the origin of the PICA. Lesions lo-
cated inside the cerebellar hemisphere, such as
tumors, intracerebral hematomas or cerebel-
lar infarctions can be also approached using a
modification of the retrosigmoid approach. In
such cases, with no need for the lateral exten-
sion towards the sigmoid sinus, both the skin
incision as well as the craniotomy are placed
more medially preventing opening of the mas-
toid air cells.
Figure 5-5 (b). Retrosigmoid approach. See text for details.

146
5.5.2. Positioning
For the retrosigmoid approach the patient is
placed in lateral park bench position with the
head and upper torso elevated so that the head
is about 20 cm above the heart level (Figure
5-5a). Two side supports are placed on the dor-
sal side, one below the level of upper shoulder
and the other at the level of pelvis. The shoul-
der support must not extend cranially from the
retracted shoulder as it would get in the way
of the surgical trajectory. One ventral side sup-
port together with a large pillow is placed to
support the thorax and the belly. The upper arm
can be placed on this pillow to rest comfort-
ably. The side supports need to be stable and
high enough to allow lateral tilting of the op-
erating table during the procedure without the
patient sliding off the table. The upper body is
rotated slightly (5–10°) backward so that the
upper shoulder can be more easily retracted
caudally and posteriorly with tape (see Figure
5-4c in previous section). The head, fixed in
head frame, is: (a) flexed a little forward; (b)
tilted laterally; and if needed (c) slightly ro-
tated towards the floor. The lateral tilt should
not be too extreme to prevent compression of
the jugular veins. The most important trick in
executing the retrosigmoid approach is to pre-
vent the upper shoulder from obstructing the
surgical trajectory. The floor of the posterior
fossa drops very steeply towards the foramen
magnum, so that the actual approach trajecto-
ry is much more from the caudal direction than
one usually expects. This is the reason why it
is so important to open the angle between the
head and the upper shoulder as much as pos-
sible. This is achieved with: (a) proper head
position (the flexion and the lateral tilt); (b)
the slight counter rotation of the upper body;
Figure 5-5 (c). Retrosigmoid approach. See text for details.

147
Figure 5-5 (d). Retrosigmoid approach. See text for details.

148
Figure 5-5 (e). Retrosigmoid approach. See text for details.

149
and (c) retraction of the upper shoulder with
tapes caudally without damaging the brachial
plexus. This shoulder retraction is the key point
of the positioning. The lower arm is supported
in place by being partially wrapped in the bed
sheet under the patient, and the sheet clamped
in place using towel clips. In addition, all the
vulnerable pressure areas (elbow joints, ulnar
nerves, hands, shoulders and brachial plexus)
need to be protected with gel pillows. Once the
positioning is ready, the lumbar drain is placed
and 50–100 ml of CSF is released before the
dura is opened.
A linear skin incision is placed about one inch
behind the mastoid process (Figure 5-5b). The
exact cranial to caudal location of the incision
varies depending on how high or low from the
foramen magnum the pathology lies. To access
the highest located structures of the lateral
posterior fossa (e.g. during microvascular de-
compression of the fifth nerve or high-lying
meningioma) the junction between the trans-
verse and sigmoid sinuses needs to be exposed
and identified, whereas, for accessing the area
close to the foramen magnum a more caudally
placed incision suffices. The junction of the sig-
moid and the transverse sinus is usually located
just caudal to the zygomatic line (a line drawn
from the origin of the zygomatic arch towards
the external occipital protuberance) and pos-
terior to the mastoid line (a cranial to caudal
line running through the tip of the mastoid
process). When planning the skin incision, it is
important to have it extend caudally enough
(Figure 5-5c). If the incision is too short and
too cranial the stretched muscles and skin will
prevent an optimal view into the posterior fos-
sa and the use of craniotome, which is coming
from the caudal and lateral direction, not just
lateral as one might initially expect. So the skin
incision has to extend several centimeters be-
low the level where caudal border of the crani-
otomy is planned.
A large, curved retractor (wound spreader, also
referred to as a mastoid retractor) under high
tension is placed from the cranial side of the
incision. If needed, a second, smaller curved
retractor can be used from the caudal direc-
tion (Figure 5-5d). The subcutaneous fat and
muscles are split along the linear incision with
diathermia. The external occipital artery runs
often across the incision. In practice, it is near-
ly always cut and has to be coagulated. After
reaching the bone of the posterior fossa, the
insertions of the muscles are detached from
the bone and the bone is followed caudally.
The level of the foramen magnum is deter-
mined with finger palpation. While progress-
ing deeper and closer to the foramen magnum,
a layer of yellowish fat is encountered. This
should be taken as a warning sign, since the
extracranial vertebral artery running on the
cranial edge of the C1 lamina is usually close
by at this point. For a simple tic craniotomy
it is not necessary to proceed any deeper to
expose the foramen magnum itself. That is re-
served only for the extended approach where
also the C1 lamina is exposed and the course
of the extracranial vertebral artery is identified.
Instead, a bony area of 3 to 4 cm in diameter
is cleared from all the muscle attachments
and the curved retractors are repositioned to
gain maximal bony exposure. One burr hole is
placed at the posterior border of the incision
and the underlying dura is carefully detached
with curved dissector without damaging the
transverse or the sigmoid sinuses (Figure 5-5e).
Two curved cuts with the craniotome are made
anteriorly towards the mastoid, one cranially
and the other caudally (Figure 5-5f). Finally,
the bone is thinned down with a craniotome

150
Figure 5-5 (f). Retrosigmoid approach. See text for details.

151
in a straight line along the anterior edge at the
border of the mastoid air cells, the bone flap is
cracked and detached (Figure 5-5g). A 2 to 3
cm bone flap is usually sufficient. A high-speed
drill is used to extend the opening closer to-
wards the temporal bone and to level the edges
(arrows; Figure 5-5g). If mastoid air cells open
these should be carefully waxed with bone wax
and a fat or muscle graft can be used to cover
the defect to prevent postoperative CSF leak.
In case of injury to the sinus and large venous
bleeding, the first measure is to get the head
higher by tilting the table into anti-Trendelen-
burg position and then the bleeding site is cov-
ered with Surgicel or TachoSil and tamponated
with cottonoids. A linear cut can be repaired
with direct suture.
The dura is opened in a curvilinear fashion with
the base towards the mastoid (Figure 5-5g).
The dural edges are elevated with sutures ex-
tended over the craniotomy dressings (Figure
5-5h). Especially when close to the junction of
the sigmoid and transverse sinus, the dura is
opened in three-leaf fashion with one of the
cuts directed exactly towards the junction to
get better exposure. Even a small scissor cut
into the sinus should be repaired immediately
with a suture. Coagulation with bipolar makes
such a hole only bigger and liga clips, although
easier to apply, tend to slide away under ma-
nipulation, usually at a moment when least ap-
preciated.
If a spinal drain was used and 50–100 ml of
CSF has been removed, the brain should be
slack after opening the dura and the drain can
be closed. But if the brain remains tight, oth-
er strategies for releasing more CSF must be
adopted. By tilting the microscope towards the
caudal region one might be able to enter the
cerebellomedullary cistern (cisterna magna) to
release additional CSF. The other option would
be to enter the cerebellopontine cistern and
to remove CSF from there, but that usually re-
quires more compression of the cerebellum and
possible injury to the cranial nerves in situa-
tions with lack of space.
To enter the cerebellopontine cistern, compres-
sion and retraction on the cerebellum is in-
creased gradually while simultaneously remov-
ing CSF with suction. To obtain optimal viewing
angle, it might be necessary to tilt the table
away from the neurosurgeon. Arachnoid lim-
iting the cistern is opened with microscissors
and now the cranial nerves can be inspected
and the pathology identified. The tentorium is
an excellent guide as a reference point for lo-
cating and identifying the cranial nerves. One
should look for the bridging veins upon enter-
ing the cerebello-pontine angle, especially at
the beginning of the dissection. If possible, the
veins should be left intact, but if the procedure
is significantly hampered by them, they should
be coagulated. The petrosal vein is an area of
debate and is the most common and prominent
vein seen when approaching the tentorium or
upper cranial nerves. It is safer to preserve this
vein as some surgeons have observed compli-
cations after its occlusion.
For closure the area over the mastoid air cells
is waxed after closure of the dura. Where the
dura cannot be closed completely in a water-
tight fashion, a dural substitute covered with
small amount of fibrin glue can be used to
close the defect. What is far more important is
to close the mastoid air cells and prevent post-
operative CSF leak using a small muscle or fat
graft and fibrin glue. There should be a three
layer (muscle, subcutis, skin) firm closure of the
wound, which helps in preventing CSF leakage.
There is occasionally debate whether to do a
craniectomy or craniotomy for suboccipital or
midline cerebellar approaches. In Helsinki it is

152
Figure 5-5 (g). Retrosigmoid approach. See text for details.

153
craniotomy! It decreases the chance of a pseu-
domeningocele or persistent headaches, and
also makes any re-exploration and recurrence
at a later date easier and safer to deal with.
Without questions, filling the craniotomy de-
fect with the patient's own bone or artificial
material provides comfort and feel of security
to the patient.
T&T:
• Park bench position, spinal drainage except
in very expansive mass lesions
• The upper shoulder retracted backwards
and downwards with tape
• Short straight incision preferred
• After dural opening, release CSF from
cisterna magna if the brain is still tight
• Start retracting the cerebellum and the
tonsils medially and slightly upwards as if
taking them in your hand
• VA, PICA and lower cranial nerves identified
– their relation with the lesion determines
the exact approach
• Out of all cranial nerves the IX-X deserve
the highest respect, even temporary
dysfunction can be dangerous
• If the lesion is 10 mm or more above the
foramen magnum, only a simple tic crani-
otomy is needed

154
Figure 5-5 (h). Retrosigmoid approach. See text for details.

156
5 | Lateral approach to foramen magnum
5.6. LATERAL APPROACH TO
FORAMEN MAGNUM
The retrosigmoid approach using the small tic
craniotomy cannot be used for pathologies that
are close to the level of the foramen magnum
(less than 10 mm). To access these lesions a
caudal extension to the retrosigmoid approach
is necessary. Some authors call this the "far lat-
eral approach". We use the actual far lateral
approach rarely. Instead, when access to the
lateral parts of the foramen magnum is neces-
sary, we settle for a so-called "enough lateral
approach", a faster and simpler modification of
the far lateral approach. The biggest difference
compared to the classical far lateral approach
is that the occipital condyle is left intact or
only a minimal portion of it is removed. In ad-
dition the vertebral artery is not transposed,
the sigmoid sinus is not skeletonized and the
extracranial/intraosseal course of the lower
cranial nerves is not exposed. The classical far
lateral approach with extensive bone removal,
and resection of the condyle requires occip-
ito-cervical fixation, which removes nearly all
movement of the neck. This causes such a sig-
nificant discomfort to the patient that we do
not recommend it unless absolutely necessary.
Our lateral approach can be combined with C1
hemilaminectomy if even more caudal exposure
is needed. The biggest challenge in the lateral
approach is to locate the vertebral artery at the
cranial edge of the C1 lamina and to keep it
intact during the various steps of craniotomy
and C1 hemilaminectomy. The other problem is
the venous plexus at the level of the foramen
magnum, which can bleed severely.
5.6.1. Indications
The most common indications for the lateral
approach are low-lying vertebral aneurysms,
foramen magnum meningiomas or low brain
stem cavernomas and intrinsic tumors. The
cranio-caudal length and location of the le-
sion determines whether the C1 lamina needs
to be resected as well. We try to leave C1 intact
to assure better stability of the craniocervical
junction. Even if C1 hemilaminectomy is per-
formed we do not use any fixation systems as
the bony defect is relatively small and the oc-
cipital condyle is not removed. The risk of swal-
lowing disturbances is very high in low-lying
lesions due to manipulation of the lower cra-
nial nerves and most patients require tracheos-
tomy to prevent aspiration. The tracheostomy
is usually performed on the first postoperative
day after tests for dysphagia have been carried
out. In the majority of the patients the function
recovers during several months after surgery.
5.6.2. Positioning
The position used for the lateral approach is
almost identical to that for the retrosigmoid
approach (see section 5.5.2). The lateral tilt of
the head towards the floor may be slightly in-
creased to give a better viewing angle towards
the foramen magnum.

157
Lateral approach to foramen magnum | 5
A straight skin incision is planned in the similar
fashion as for the retrosigmoid approach. The
incision is placed about one inch behind the
mastoid. The incision starts below the zygo-
matic line but extends more caudally, usually
4–5 cm caudal from the tip of the mastoid. The
intial exposure is carried out in the same way
as for the retrosigmoid approach. The subcu-
taneous fat and muscles are divided in a linear
fashion and a large curved retractor is used
to open the wound. The bone of the posterior
fossa is exposed and the location of the fo-
ramen magnum and the C1 lamina is identified
with finger palpation. From this point onward
the rest of the foramen magnum exposure and
vertebral artery exposure should be carried out
under the magnification of the surgical micro-
scope.
The next step is to identify the course of ex-
tracranial vertebral artery. Microdoppler can
be used for this purpose. First the C1 lamina
is exposed with blunt dissection using cotton
balls held by a hemostat. The lamina should be
exposed close to the transverse process of the
C1. The vertebral artery, after passing through
the transverse foramen of the C1, should be
coursing along the cranial surface of the C1
lamina towards the midline before it enters
intradural space at the level of the foramen
magnum. It is crucial to identify this whole ex-
tradural segment of the vertebral artery as well
as the exact place where it becomes intradural.
With the vertebral artery visualized the rest of
the posterior fossa bone can be safely cleaned
from attached muscles all the way down to the
foramen magnum that is now clearly exposed.
At the anterior border of the exposure the
condyloid canal is often encountered marked
by rather heavy venous bleeding. The occipital
emissary vein runs through this channel, and
connects to the suboccipital venous plexus. The
bleeding can be stopped with bone wax and
later on using "hot drilling" with diamond drill.
A second medium or large curved retractor is
inserted from the caudal part of the incision to
maximize the exposure.
One burr hole is placed at the posterior border
of the exposed bone and the underlying dura is
carefully detached with a curved dissector. The
curved dissector can be also inserted from the
caudal direction through the foramen magnum,
but only close to the midline and with minimal
force. The first cut with the craniotome is di-
rected from the burr hole slightly superior and
towards the mastoid as far as it easily pro-
ceeds. Then the second cut is made from the
burr hole in the caudal direction all the way to
the foramen magnum, well posterior to where
the vertebral artery enters intradural space. The
bone ridge at the foramen magnum is quite
thick and if the cut cannot be made directly,
the bone should at least be thinned down with
either drill or craniotome. With the two cuts
ready, the bone is thinned down along the an-
terior border of the planned bone flap with ei-
ther craniotome or high-speed drill. The bone
flap is then cracked and removed. The anterior
borderline of the craniotomy should be placed
anterior to the intradural origin of the verte-
bral artery. The ligaments attached to the fo-
ramen magnum region are usually quite strong
and they might need to be cut before the bone
flap can be lifted. Removal of the bone is of-
ten followed by heavy venous bleeding either
from the paravertebral venous plexus or the
dural venous sinus surrounding the foramen
magnum. Lifting the head higher, tamponation
with Surgicel or injecting fibrin glue settles the
situation.
With the bone flap removed, the bony window
needs now to be extended in the anterior di-
rection. The table is lifted higher to have a bet-
ter view towards the condyle and then, using a
high-speed drill, bone is removed in this direc-
tion. We prefer to use a diamond drill as it also

158
5 | Lateral approach to foramen magnum
coagulates bleedings from the bone. We do not
remove the occipital condyle or skeletonize the
sigmoid sinus. Also the hypoglossal canal is left
intact. If the mastoid air cells are opened, care-
ful waxing and muscle or fat grafts with fibrin
glue are applied during closure to prevent post-
operative CSF leak. In case the C1 extension for
the approach is planned, C1 hemilaminectomy
is carried out next. The C1 lamina, which was
exposed earlier, is drilled away with a high-
speed drill. Drilling starts close to the midline
and extends towards the transverse foramen.
Usually, it is not necessary to remove all the
bone covering the vertebral artery inside the
transverse foramen, as we seldom need to mo-
bilize the artery. With the bone removed, the
ligament is removed to expose the dura of the
lateral spinal canal, but with care to not harm
the C2 root.
The dura is opened posterior to the intradural
origin of the vertebral artery with a straight
incision, which is curving anterior at the most
cranial part of the craniotomy. Sutures extend-
ing over the craniotomy dressings are used to
lift the dura and to prevent oozing from the
epidural space. CSF can be released from the
foramen magnum that can be well accessed
with this approach. During all further steps
of the dissection a lot of care is needed not
to severe the lower cranial nerves. It might be
necessary to lift the cerebellar tonsil a little to
access the structures on the lateral aspect of
the brain stem hidden by the tonsil.
Closure is performed in the same way as with
the retrosigmoid approach. The dura is closed
watertight if possible, the bone is placed back,
all the mastoid cells are occluded, often with
a fat or muscle graft, and the wound is closed
in layers. The C1 hemilaminectomy is left as
such.
T&T:
• Park bench position, spinal drainage useful
• Straight, rather low-placed incision
• Bone removed laterally only as much as
needed, excessive bone removal avoided
• Occipital condyle is not resected, occipito-
cervical fixation not needed
• Cutting of 1-2 denticulate ligaments helps
in releasing tension of the medulla
• Vertebral artery can be temporarily clipped
also extracranially
• VA, PICA and lower cranial nerves identi-
fied – relation to the lesion determinates
how to proceed to the lesion
• Respect the IX-X cranial nerves, even
temporary dysfunction is dangerous

159
Lateral approach to foramen magnum | 5

160
5 | Presigmoid approach
Figure 5-6 (a). Presigmoid approach. See text for details.
5.7. PRESIGMOID APPROACH
In our practice, for lesions purely in the poste-
rior fossa we prefer the retrosigmoid approach
and for those only in the middle fossa the sub-
temporal approach. But for lesions that extend
to both middle- and posterior fossa, we use a
combination of these two approaches: the pre-
sigmoid-transpetrosal approach with partial
petrosectomy. For convenience reasons, we call
this approach just "presigmoid approach". The
presigmoid approach classically refers to an
approach that is used to access posterior fossa
anterior to the sigmoid sinus by means of per-
forming a transmastoid approach. This classical
approach gives only very limited access to the
middle fossa and should not be confused with
the approach we call presigmoid approach,
which refers to an approach with by far wider
exposure but less drilling of the mastoid.
5.7.1. Indications
We use the presigmoid approach to access
mainly two types of lesions: (a) low-lying basi-
lar tip and trunk aneurysms; and (b) petroclival
tumors, mainly meningiomas. Most basilar tip
aneurysms can be accessed either by (a) trans-
Sylvian route, if they are located high above
the posterior clinoid, or (b) by subtemporal ap-
proach if they are at or just below the level of
the posterior clinoid. Infrequently, the basilar
tip is located extremely low below the poste-
rior clinoid, where the aneurysm itself can be
accessed via the subtemporal route but placing
the temporary clip on the basilar artery would
not be possible. For such aneurysms we use
the presigmoid approach that combines ac-
cess from both the middle and the posterior
fossa. The other type of aneurysms requiring
the presigmoid approach are basilar trunk an-

161
Presigmoid approach | 5
Figure 5-6 (b). Presigmoid approach. See text for details.
eurysms. The presigmoid approach allows good
visualization of the midbasilar region as well
as the posterior parts of the middle fossa and
the petrous bone. The presigmoid approach can
also be used to access the P2 segment of the
posterior cerebral artery in certain bypass pro-
cedures. On the other hand, the presigmoid ap-
proach is time consuming (even in experienced
hands it takes at least one hour), it is possi-
ble to injure the transverse or sigmoid sinus,
and the risk of postoperative CSF leak is much
higher than in the simple subtemporal or retro-
sigmoid approach. So, the presigmoid approach
should be used with caution and only when
truly necessary. The mastoid air cells are always
opened during the presigmoid approach, and a
very careful covering with temporal muscle or
fat is necessary when closing.

162
Figure 5-6 (c). Presigmoid approach. See text for details.
5.7.2. Positioning
The patient is placed in lateral park bench po-
sition like for the subtemporal approach (see
section 5.4.2.) (Figure 5-6a). A lumbar drain or
ventriculostomy is mandatory in the same way
as for the subtemporal approach. It is not pos-
sible to execute the presigmoid approach with-
out a well-relaxed brain as the brain retraction
would cause inadvertent damage.
The skin incision starts in front of the ear curv-
ing backwards in the same fashion as for the
subtemporal approach (Figure 5-6b). The dif-
ference is that the incision then extends cau-
dally about one inch behind the mastoid line as
it would do for the retrosigmoid approach. The
skin-muscle flap is retracted in one layer fron-
to-caudally with strong spring hook retraction
(Figure 5-6c). The muscles are detached all the
way down to the external auditory canal and
the whole temporal bone is exposed, including

163
Figure 5-6 (d). Presigmoid approach. See text for details.
the origin of the zygoma and the mastoid proc-
ess. Care is taken not to accidentally enter or
tear the skin near or at the external auditory
canal, since the skin is very thin here.
Three to four burr holes are usually used (Figure
5-6d). The first one just at the anterior border
of the exposed area of the temporal bone close
to the origin of the zygoma. The second one at
the most cranial part of the exposed tempo-
ral bone. The third one at the posterior border
inferior to the transverse sinus, and optionally
a fourth one at the posterior border superior
to the expected course of the transverse sinus,
especially if dura is very tightly attached to the
inner surface of the skull, in which case there is
a high risk of injury to the venous sinuses. The
dura is carefully detached with a curved dis-
sector and Yaşargil-type flexible dissector. At
the level of the posterior fossa the aim is to get
close to the sigmoid sinus. Using a craniotome
the burr holes are connected (Figure 5-6e). One

164
Figure 5-6 (e). Presigmoid approach. See text for details.
additional cut is made from the burr hole clos-
est to the zygoma caudally and slightly poste-
rior towards the anterior aspect of the petrous
bone. Then a second cut is made from the
posterior fossa burr hole caudally and curving
anterior towards the mastoid process. Finally,
the remaining bone ridge is thinned down in
a curved fashion with craniotome blade or a
high-speed drill and the bone flap is cracked
and detached. It requires special attention to
not accidentally tear the sigmoid sinus. Some-
times, there are emissary veins running inside
the bone and connected to the junction of the
transverse and sigmoid sinuses that may start
to bleed heavily while removing the bone. El-
evating the head, Surgicel tamponation and bi-
polar coagulation usually solve the problem.
With the bone flap removed, we normally see
the transverse sinus, dura of the posterior fossa,
and dura of the middle fossa. The junction be-
tween the transverse and sigmoid sinuses is at
least partially visible. The dura should be slack
due to the lumbar drain. It would be very dif-
ficult to proceed with the exposure of the pre-
sigmoid dura unless the already exposed dura
and the sinuses can be slightly compressed.
With the help of a blunt, straight dissector or

165
Figure 5-6 (f). Presigmoid approach. See text for details.
elevator the dura is detached from the tempo-
ral bone. Special care is taken not to acciden-
tally tear the sigmoid sinus. Detaching the dura
has to be performed both from the posterior
fossa side as well as from the middle fossa. Re-
tractors are then put in place to compress the
dura downwards away from the mastoid and
the petrous bone to provide a safe margin for
drilling.
Drilling of the mastoid and the petrous bone
is often the most time-consuming part of the
presigmoid approach (part of the temporal
boned removed by drilling is shown schemati-
cally; Figure 5-6f). It is done under the micro-
scope. The high-speed drilling starts with a
cutting ball drill head to remove the roughest
edges but soon we switch to a large diamond
drill. Unlike the classical transmastoid ap-
proach, we start drilling from the posterior and
superior border of the exposed temporal bone
and we proceed deeper in layers. We do not try
to perform total mastoidectomy, and neither to
approach the semicircular canals. Only as much
drilling is performed as is really necessary to
expose the dura anterior to the sigmoid sinus,
the superior petrous sinus and the dura of the
floor of the middle fossa. It is safer to perform

166
Figure 5-6 (g). Presigmoid approach. See text for details.
drilling in the deeper parts under higher mag-
nification of the microscope. By making the
initial craniotomy large enough extending well
in the retrosigmoid area, the drilling angle for
exposing safely the whole sigmoid sinus is bet-
ter and requires less bone to be removed from
the anterior parts of the mastoid region. There
is also less risk for accidentally entering the
semicircular canals. The temporal bone is very
hard in general, except for the mastoid region
containing a lot of air cells. The drilling pro-
ceeds stepwise with the dura being detached
each time before moving a little deeper. When
the drill is not rotating, the ball shaped dia-
mond drill tip can be used for detaching the
dura instead of a dissector.
Finally, after partial petrosectomy, the sigmoid
sinus with its steep descending S-shape should
be fully visualized, the presigmoid dura ex-
posed, the superior petrous sinus visible, and
the posterolateral part of the middle fossa
accessible (Figure 5-6g). Dural incision of the
posterior fossa is made under microscope some
millimeters anterior to the sigmoid sinus with
the incision extending all the way towards the
superior petrous sinus, which is still left intact
(Figure 5-6g). If necessary, the cerebellopontine
cistern can be carefully entered and additional
CSF released from there. Dura of the middle
fossa is then opened in a curved fashion and
everted basally, the incision again extending
towards the superior petrous sinus. The petrous
sinus (arrow; Figure 5-6h) is then divided and

167
Figure 5-6 (h). Presigmoid approach. See text for details.
the two incisions connected. When dividing the
superior petrous sinus, we prefer using sutures
since these can be used also to lift the dura.
Each suture is placed twice around the sinus
through the tentorium and a knot is tied. The
sinus is divided in between these two sutures.
Hemoclips can slide easily off and cause un-
wanted bleeding.
With the dura opened (Figure 5-6h), one more
step remains: the cutting of the tentorium.
Before cutting the tentorium, we enter sub-
temporally and inspect for the course of the
fourth nerve. The tentorium needs to be divided
well anterior to the drainage of vein of Labbé
and posterior to the tentorial insertion of the
fourth nerve. Usually, there are also less venous
sinuses inside the tentorium at this level, which
helps the task. We start cutting the tentorium
in stepwise manner from the lateral (corti-
cal) direction. Before each cut the tentorium
is coagulated with blunt bipolar forceps, it is
checked from supra- and inftratentorial direc-
tion, and a small cut is made. This is continued
until the tentorial edge, where the course of the
fourth nerve is once again checked inftratento-
rially before making the final cuts. A small cot-
tonoid can be used to protect the fourth nerve.
The mobile anterior portion of the tentorium
can be folded over and tucked in the anterior
direction beneath the temporal lobe. If neces-
sary, retraction of the anterior tentorial portion
can be increased by fixing the folded part of
the tentorium to the dura of the middle fossa

168
with a small aneurysm clip like in the subtem-
poral approach. During all steps of opening the
dura and temporal lobe retraction, special care
must be paid not to overstretch or tear the vein
of Labbé.
When closing, special care must be taken to
prevent postoperative CSF leak. The dura should
be closed water tight, and all the mastoid air
cells need to be covered. We usually use fat
graft, everting of the inner portion of the tem-
poral muscle over the air cells and attaching it
to the dura, bone wax, and fibrin glue to seal
the dura off. The cut in the tentorium is not
repaired, but the tentorium is everted back in
its normal anatomical position.
T&T:
• Park bench position, always spinal drainage
• Reversed J-shaped flap starting in front of
the ear and terminating behind the mastoid
• One layer skin-muscle flap with heavy
retraction of the flap downwards until the
level of the external ear canal
• 3 to 4 burr holes, and cracking of the basal
part after partial drilling above transverse
and sigmoid sinuses
• Additional bone removal under the micro-
scope until sacculus/internal acoustic
canal is reached
• Presigmoid dural opening continues
temporally and suboccipitally with stitch
ligation of the superior petrosal sinus
• Preserve the draining veins (vein of Labbé
and others)
• The tentorium is cut under the microscope
behind the trochlear nerve and in front of
the vein of Labbé

170
5 | Sitting position – Supracerebellar infratentorial approach
A
5.8. SITTING POSITION – SUPRACEREBELLAR
INFRATENTORIAL APPROACH
There are two types of posterior fossa midline
approaches that we use in Helsinki: (a) the su-
pracerebellar infratentorial approach; and (b)
the posterior midline approach into the fourth
ventricle and the foramen magnum region.
What both of these approaches have in com-
mon is, that the patient is kept in sitting po-
sition. The advantages of the sitting position
compared to the prone position are that the
use of gravity facilitates drainage of any bleed-
ing and CSF, decreasing the venous congestion,
and it offers a superior anatomical view for
certain pathologies. The disadvantages on the
other hand include risks of air embolism, mye-
lopathy of the cervical spine, and hypotension.
Risk-benefit decisions have to be made based
on patient's age, general condition, and other
diseases. Especially older patients with heart
problems are unlikely to tolerate sitting posi-
tion. Patients with septal defects of the heart,
such as patent foramen ovale, and blood flow
across this defect have a much higher risk for
air embolism and should be considered for a
different approach. Also patients with signifi-
cant cervical spine disease require extra cau-
tion to avoid spinal cord compression injury.
The anesthesia risks and special measures for
sitting position are described in detail in sec-
tion 3.7.3.
During sitting position, an even closer co-
operation between the neurosurgeon and the
anesthesiologist is required than usually. If the
anesthesiologist detects any signs of possible
air embolism, he or she should immediately
inform the neurosurgeon, who reacts without

171
Sitting position – Supracerebellar infratentorial approach | 5
B
Figure 5-7 (a-b). Supracerebellar infratentorial approach. See text for details.
any delay and takes appropriate counteraction
measures (Table 5-1). In many institutions the
sitting position was earlier used regularly but
gradually went out of fashion due to the fear
of complications. All we can say is that in Hel-
sinki the sitting position is being used regularly,
safely and effectively in all those cases where
we see a true benefit offered by the position
as compared to other possible approaches. We
take only simple practical precautions and min-
imum of complex preoperative investigations. A
skilled and dedicated team together with cer-
tain preventive measures are needed to avoid
possible complications as much as possible.
5.8.1. Indications
The supracerebellar infratentorial approach is
used to reach lesions located at the pineal re-
gion and the tectum of the midbrain. We use
the supracerebellar infratentorial approach
most often for pineal region lesions, since this
approach evades most of the large draining
veins of the pineal region located superior to
the direction of this approach. In the sitting
position, the gravity pulls on the cerebellum,
which falls down and exposes this region. In
addition, the supracerebellar infratentorial ap-
proach can be also used to gain access to tento-
rial meningiomas, some AVMs, aneurysms and
intrinsic tumors of the superior surface of the
cerebellum. Utmost vigilance is required when
operating on such a pathology near the trans-
verse sinus and confluence of sinuses. Prepara-
tion and caution is required during all stages

172
Figure 5-7 (c). Supracerebellar infratentorial approach. See text for details.

173
of the craniotomy and also when approaching
the possible attachment to the tentorium or
the region of the venous sinuses. A small open-
ing in the venous sinus can easily occur but is
difficult to notice in the sitting position due to
low venous pressure.
The supracerebellar infratentorial approach
can be carried out either as a direct midline
approach or a paramedian approach. Earlier we
used the midline approach quite frequently, but
nowadays we have switched almost exclusively
to the paramedian approach. With the para-
median approach there are several advantages
compared to the classical midline supracere-
bellar approach. Apart from fewer veins in the
surgical trajectory, the other advantage is that
the tentorium does not rise as steeply upwards
lateral from the midline, so less retraction/
compression of the cerebellum in needed. In
addition, there is no need to extend the crani-
otomy over the sinus confluens in a paramedian
approach, which decreases the risk of possible
venous damage and air embolism. The great-
est disadvantage of the paramedian approach
is the more difficult orientation and choosing
the right trajectory towards the centre of the
quadrigeminal cistern and the pineal region.
5.8.2. Positioning
Placing the patient in a sitting position is a
demanding task and requires an experienced
team. There are several key factors that need
always to be remembered (Table 5-1). The ac-
tual practical tricks may vary from department
to department. Here we describe in detail how
the sitting position is executed in Helsinki. The
sitting position requires special equipment and
a mobile operating table.
What we call a sitting position in Helsinki
would be probably better described as praying
position or forward somersault position, with
the upper torso and the head bent forward and
downward (Figure 5-7a). During surgery, the
operating table is often tilted even further for-
ward to gain optimal view into the posterior
fossa along the tentorium. A very important
Table 5-1. General setup for sitting position in Helsinki
• Mobile OR table
• Mayfield-Kees head clamp
• Special system for attaching the head frame to the table (trapeze)
• G-suit trousers (inflated to 40 mmHg) or loosely tied elastic bandage
• Urinary catheter, not kinked against the G-suit
• Shoulders left free at least 10 to 15 cm above the cranial edge of the table
• Large suction cushion wrapped around the upper body and arms to prevent movement
• Pillow beneath knees for 30 degree flexion, knees kept in straight line
• Flat board against the feet to prevent sliding caudally
• Large pillow on top of the belly to support both arms
• All the pressure areas protected
• Shoulder taped to the table to prevent falling forward
• Safety belt around the pelvis
• At least two fingers must fit between the chin and the sternum
• The endotracheal intubation tube secured to the clamp system
• Anesthesiologist must have access to the intubation tube and both jugular veins
• Precordial Doppler device above the right atrium

174
Figure 5-7 (d). Supracerebellar infratentorial approach. See text for details.

175
factor when planning the supracerebellar in-
fratentorial approach is to remember that the
tentorium is actually shaped like a tent, and
it rises steeply upwards especially close to the
midline. Bending the patient's head forward for
about 30° makes the tentorium almost hori-
zontal providing good viewing angle even to
the most cranial portions of the posterior fossa.
At the same time it allows the neurosurgeon
to rest his or her arms on the patient's shoul-
ders and back as a form of arm support. This
is less tiring for the neurosurgeon than if the
approach angle was more upward.
The patient is placed on the operating table
so that there are two table elements support-
ing the upper body. The pelvis should be at the
joint from which the table can be bent into a
90° angle. The whole upper body and pelvis
rests on a large suction mattress. In addition
the patient is fitted with G-suit trousers that
are inflated to the pressure of 40 mmHg. If
a G-suit is not available, as well as in small
children, both lower limbs must be loosely tied
with elastic bandage from the toes all the way
up to the groin. The sitting position is the only
position where we routinely prefer to use May-
field head clamp instead of the Sugita head
frame. There is one extra joint on the Mayfield
clamp that makes head positioning easier for
the sitting position. The three pin Mayfield
head frame is attached to patient's head before
the actual positioning starts. The neurosurgeon
then holds the head until the position is final-
ized and the head frame fixed to the trapeze
clamp system.
The positioning starts with bending of the ta-
ble into anti-Trendelenburg position while si-
multaneously elevating the upper torso. A 90°
angle is usually the most any modern OR table
allows at one joint. Once this has been reached,
it is necessary to check that the patient is sit-
ting so that the shoulders reach 10–15 cm
above the level of the most cranial edge of the
table. If not, as is usually the case with chil-
dren, then one or several extra cushions need
to be inserted underneath the buttocks to lift
the patient upward. Without this free shoulder
margin, the optimal approach angle from cau-
dal direction cannot be achieved later during
surgery. With the shoulders at optimal height,
the most cranial table section is bent forward,
in most tables manually, for about 30–40°. This
pushes the upper body and shoulders forward.
The Mayfield head frame is then fixed to the
trapeze clamp system and all the joints are
tightened, and the locking screw on the head
frame is locked. A pillow is inserted beneath
the knees to provide little flexion of the knees.
A flat board, fixed to the table railings, is placed
to keep the ankles in neutral position and to
prevent the patient from sliding downwards.
The arms are rested on a large pillow on top
of the belly. Finally, the large suction mattress
which was earlier placed beneath the patient's
upper torso is wrapped around the upper body
and the arms and deflated to form a sort of
shell protecting the whole upper body and pre-
venting any undesired slipping or sliding. Addi-
tionally, both shoulders can be fixed to the OR
table with thick tape to prevent the upper body
from falling forward during extreme forward
tilting of the table.
The head position varies slightly depending on
the planned approach. Irrespective of the ap-
proach, the neck is always flexed forward. This
should not be overdone to prevent compression
of the airways as well as the possible spinal
cord injury. At least two fingers should fit be-
tween the chin and the sternum. If the plan is
to use a midline incision, then the head should
not be rotated or tilted lateral at all. It is only
flexed with the nose pointing exactly forward.
However, for the paramedian approach a slight

176
Figure 5-7 (e). Supracerebellar infratentorial approach. See text for details.

177
head rotation is necessary. The head is rotated
5–10° to the side of the planned approach,
without any lateral tilt.
With the patient in the proper position, a pre-
cordial Doppler device is attached over the right
atrium and all the joints of the clamping sys-
tem are checked once more to make sure that
they are tightened. All the pressure points need
to be covered with pillows. Special attention
is paid to peroneal nerve at the lateral aspect
of the knee which can easily get compressed
if the knees fall outward. Safety belt is placed
over the pelvic region.
A straight skin incision is planned 2–3 cm lat-
eral from the midline (Figure 5-7b). The incision
starts about an inch cranial from the external
occipital protuberance (the inion) and extends
caudally towards the level of the cranio-cervi-
cal junction. For a right-handed neurosurgeon
a right-sided approach is more convenient if
the target is located in the midline or lateral-
ized to the right. The muscles are split in a ver-
tical fashion all the way down to the occipital
bone (Figure 5-7c). A curved retractor is used
to spread the wound from the cranial direc-
tion. The muscle insertions are detached with
diathermia and the occipital bone is exposed
(Figure 5-7d). The medial border of the expo-
sure is almost at the midline. A second curved
retractor can be used to get a better exposure
and additionally a third smaller curved retrac-
tor can be used caudally. It is enough to expose
only about 3–4 cm of bone below the level of
the transverse sinus, so that the exposure does
not have to extend anywhere near the foramen
magnum.
One burr hole is placed about 3 cm lateral from
the midline over the occipital lobe superior
to the transverse sinus (Figure 5-7e). In older
patients with tightly attached dura a second
burr hole can be placed inferior to the trans-
verse sinus. The dura is carefully detached with
a curved dissector especially along the trans-
verse sinus. Two cuts with a craniotome are
made to detach a 3-4 cm diameter bone flap
(Figure 5-7e). Both cuts start from the burr
hole, they curve sideways and join caudally
exposing about 2 cm of the dura below the
level of the transverse sinus. It is necessary to
have the superior border of the bone flap above
the transverse sinus to allow retraction of the
transverse sinus upwards. Some drill holes are
prepared for the use of tack-up sutures at the
end of the procedure.
When detaching the dura and performing the
craniotomy, the most critical area is the site of
the sinus confluens; its lesion may cause fatal
complications, and all efforts should be made
to preserve it as well as both transverse sinus-
es. The medial border of the craniotomy should
be left about 10 mm lateral from the midline.
There are usually several venous canals running
inside the bone close to the sinus confluence.
By keeping the craniotomy lateral to this region,
there is much less risk of opening the venous
canals and subsequent air embolism. Even with
these preventive measures, a sudden decrease
in end-tidal CO2
pressure or the sound from the
precordial Doppler device is indicative of an air
embolism. In such a situation the bone flap
should be promptly removed, and the damaged
vein sealed. Compression of the jugular veins
by the anesthesiologist is extremely helpful in
localizing the bleeding site. While sealing one
possible bleeding site, the rest of the wound
should be covered with a moistened swab. Me-
ticulous waxing of the craniotomy edges closes
the venous channels inside the bone, which

178
Figure 5-7 (f). Supracerebellar infratentorial approach. See text for details.

179
cannot be sealed otherwise. In general, the re-
action to possible air embolism needs always
to be swift and both the neurosurgeon and the
anesthesiologist should be well familiar with
all the counteraction measures (Table 5-2). In
our series, we have had no major complications
due to air embolism. With the situation under
control, we proceed with the surgery, we do not
abandon the procedure.
The dura is usually opened under the microscope
to avoid accidental injuries of the sinuses. The
dura is opened in a V-shaped fashion with the
base towards the transverse sinus (Figure 5-7f).
The dural flap is reflected cranially with several
lifting sutures. Also the remaining dural edges
are lifted with sutures placed over the crani-
otomy dressings to prevent both oozing from
the epidural space as well as compression of
the cortical cerebellar veins (Figure 5-7g). The
occipital midline sinus can be usually avoided
as the dural opening does not have to extend
all the way to the midline. If this sinus is acci-
dentally opened, it does not bleed profusely in
the sitting position unlike in the prone position.
The cut should be sealed immediately with one
or several sutures as sutures do not acciden-
tally slide off like e.g. hemoclips do.
Since the approach is slightly lateral from the
midline, there are usually no major bridging
veins obstructing the view. The superior cere-
bellar vein and draining veins coming from the
surface of the cerebellum are typically close to
the midline and thus avoided in this approach.
In case there is a vein obstructing the approach
towards the pineal region it may be necessary
to coagulate and cut it, preferably closer to
the cerebellum than to the tentorium. In some
cases, we even cut one or more of these veins
early on (prophylactically), as they are much
more difficult to treat if severed accidentally
later during some of the critical steps of the
dissection. It is better to save as many of the
draining veins as possible to prevent venous in-
farction of the cerebellum.
Once the arachnoid adhesions and possible
bridging veins between the cerebellum and the
tentorium have been coagulated and cut, the
cerebellum falls down, allowing a good surgical
view without brain retraction. Opening of the
Table 5-2. Action during air embolism in sitting position
• Sudden drop in pCO2
is the most important clue of air embolism
• Anesthesiologist informs the neurosurgeon immediatelly
• Anesthesiologist compresses both jugular veins at the neck to increase the venous pressure
• If the bleeding point is seen, it is sealed (in muscle with coagulation, in bone with wax or
glue, in dura by suturing or clips)
• If the bleeding point is not evident, the wound edges as well as the muscle is covered with
moist surgical swabs and the deeper parts of the operative field are flushed with saline
• In semi-sitting position the head should be lowered
• Bony edges are carefully waxed, it is often a venous bone channel which is the cause of
air embolism
• PEEP is added if air embolism continues and the site is not found
• pO2
is carefully followed, decrease in pO2
indicates serious air embolism
• The neurosurgeon must act swiftly and systematically until the situation resolves
• Once the situation is again under control, we proceed with the surgery, we do not abort
the procedure

180
Figure 5-7 (g). Supracerebellar infratentorial approach. See text for details.

181
dorsal mesencephalic cisterns along the ap-
proach and removal of CSF improves the surgi-
cal view and provides more space for further
dissection. Tilting the table forward provides
better visualization of the tentorium.
The arachnoid structures can be thick and
opaque complicating identification of anatom-
ical structures. At this point, distinguishing the
deeply located veins from the dark blue-colored
cisterns is crucial. Exposure of the precentral
cerebellar vein, and coagulation and cutting
of this vein if needed, clears the view so that
the vein of Galen and the anatomy beneath it
can be identified. This is the most important
part of the operation, and sometimes the thick
adhesions associated with chronic irritation of
the arachnoid caused by the tumor makes this
dissection step very tedious. Generally, we start
the dissection laterally. Once we find branches
of the posterior choroidal artery and the pre-
central cerebellar vein the orientation towards
other anatomic structures becomes easier. Spe-
cial care is needed not to damage the posterior
choroidal arteries during further dissection. The
use of high magnification is crucial as well as
the proper length of instruments.
T&T:
• Neurosurgeon fixes the head clamp and is
in charge of the positioning all the way
• The position should allow the neurosur-
geon to rest his or her arms on the
patient's shoulders
• Exact head positioning according to the
3D location of the lesion
• Usually one burr hole is enough
• All the bleeding must be stopped even
more carefully than in other positions
• Utmost care is needed close to venous
sinuses due to high risk of air embolism
• Dura is better opened under the microscope
• Bridging veins should be left intact as
much as possible
• Close to pineal region the dissection
should start laterally
• Longer instruments might be necessary
• Perfect hemostasis throughout the
procedure, no oozing is allowed

182
Figure 5-8 (a). Midline approach to fourth ventricle. See text for details.
5 | Sitting position – Approach to the fourth ventricle and foramen magnum region

183
Sitting position – Approach to the fourth ventricle and foramen magnum region | 5
5.9. SITTING POSITION –
APPROACH TO THE FOURTH VENTRICLE
AND FORAMEN MAGNUM REGION
The other most common use for sitting position
in Helsinki is to approach the posterior fossa
lesions in the midline, usually located at the
level of vermis, fourth ventricle and down to
the foramen magnum. All the same rules for
sitting position and risks apply as for the su-
pracerebellar infratentorial approach (see sec-
tion 5.8.). The anesthesiologic principles of the
sitting position were reviewed in section 3.7.3.
Compared to the supracerebellar infratentorial
approach the greatest differences are: (a) no
rotation of the head; (b) incision is exactly on
the midline; (c) the incision starts lower and ex-
tends more caudally; (d) the transverse sinuses
are not exposed, the craniotomy is placed be-
low their level; and (e) the craniotomy extends
to both sides of the midline.
5.9.1. Indications
Thisapproachprovidesexcellentvisualizationof
all the midline structures of the posterior fossa.
It allows access to the posterior aspect of the
medulla oblongata and the brainstem through
the fourth ventricle. With this approach it is
possible to enter into the fourth ventricle from
the caudal direction in between the cerebellar
tonsils without dividing the vermis, and with
sufficient forward tilt of the operating table,
even the aqueduct can be visualized. Also, both
distal PICAs can be accessed. We usually use
this low posterior fossa midline approach to
access midline tumors of the fourth ventricle,
vermis and the cisterna magna region, such
as medulloblastomas, pilocytic astrocytomas,
ependymomas, or vascular lesions such as mid-
line cavernomas of the fourth ventricle and
posterior brainstem and distal PICA aneurysms.
For lateral lesions in the posterior fossa we pre-
fer the lateral park bench position. The advan
tages of the sitting position compared to prone
position are mainly related to a more advanta-
geous viewing angle into the fourth ventricle,
as the approach is oriented from a more caudal
direction, and the possibility of adjusting the
view by rotating the table forward even further.
To obtain the same kind of approach angle in
prone position requires placing the head well
below the heart level, which worsens the ve-
nous outflow and increases bleeding.
5.9.2. Positioning
The positioning is almost identical to that of
the supracerebellar infratentorial approach
(see section 5.8.2.) (Figure 5-8a). As with the
supracerebellar infratentorial approach, our
sitting position is more like a forward somer-
sault position with the head bent downwards.
The only difference for the low midline ap-
proach is that the head is not rotated. The neck
is only flexed forward leaving at least two fin-
gers between the chin and the sternum. Again,
there is no lateral tilt. All the steps of position-
ing are carried out in the same way as already
described above (see section 5.8.2.).
The skin incision is placed exactly on the mid-
line (Figure 5-8b). It starts just below the level
of the external occipital protuberance and ex-
tends caudally all the way down to the C1–C2
level. Unless the incision is extended caudally
enough, it will not be possible later to insert the
craniotome in an appropriate angle to reach all
the way down to the foramen magnum. It is
important to remember that the posterior fossa
drops steeply towards the foramen magnum,

184
Figure 5-8 (b). Midline approach to fourth ventricle. See text for details.

185
which is almost horizontal. The muscles are
split with diathermia all the way to the occipi-
tal bone (Figure 5-8c). One large curved retrac-
tor is placed from cranial and the other from
caudal direction. The muscle insertions are cut
and the occipital bone is exposed. Finger pal-
pation is used to identify the level of the fo-
ramen magnum as well as the spinous process
of the C1, which is partially exposed with blunt
dissection using cottonoid balls. When releas-
ing the muscles and exposing the bone close
to the foramen magnum, care is needed not to
accidentally cut into the vertebral artery. Up
to 1–2 cm from the midline is safe. The other
problem may be the large venous epidural si-
nuses at the foramen magnum. If the posterior
atlanto-occipital ligament is cut accidentally,
these veins may start to bleed heavily.
At this point the occipital bone should be ex-
posed all the way down to the foramen mag-
num. One burr hole is placed about 1 cm par-
amedian to the midline, well below the level
of the transverse sinus (Figure 5-8d). In older
patients with densely attached dura another
burr hole can be placed on the opposite side
of the midline. The dura is carefully detached
from the underlying bone first with a curved
dissector and then with a flexible dissector. The
dura should be released all the way towards
the foramen magnum. A critical region to re-
lease the dura from is next to the burr hole
towards and over the midline overlying the oc-
cipital sinus and the falx cerebelli. Two cuts are
made with the craniotome (Figure 5-8e). The
first one curving slightly lateral and down to
the foramen magnum. The other cut starts first
over the midline to the opposite side and then
curves laterally and caudally to the foramen
magnum. These two cuts are not joined and
10–20 mm of bone is left between them at the
foramen magnum. The bone flap, held from its
cranial edge with a large rongeur, is everted
downwards and cracked. The bone is thicker
around the foramen magnum and it might be
necessary to thin it further down along the
craniotome cut before the bone flap can be
lifted (Figure 5-8e). There are also dense at-
tachments to the atlanto-occipital ligament,
which often need to be cut with scissors. Dam-
age to the epidural venous plexus is most likely
to happen during this step, so extra caution is
needed. With the bone removed we should be
able to distinguish medial aspects of both cere-
bellar tonsils as well as the medulla oblongata,
and the occipital sinus all covered with dura.
A high-speed diamond drill or a small rongeur
is used if needed to remove bone in the lat-
eral direction on both sides to expose the fo-
ramen magnum a little more. Few drill holes
are prepared to be used with tack-up sutures
during closure. We do not routinely remove the
spinous process or the lamina of C1 vertebra.
In our experience, the total removal of C1 arch
does not provide any additional benefit regard-
ing the exposure of the lower posterior fossa,
but carries significant morbidity. It is performed
only when truly necessary in lesions that ex-
tend well below the level of C1.
The dura is opened under the operating micro-
scope in X-like fashion. The first reversed V-
shaped dural leaf is cut from the midline below
the occipital sinus, everted caudally and at-
tached tightly to the muscles with a suture to
prevent venous bleeding. Then two additional
cuts are made in cranio-lateral direction on
both sides over the cerebellar tonsils avoiding
the occipital sinus in the midline. All the dural
leafs are lifted up with sutures placed over the
craniotomy dressings. Recently, we have often
been satisfied with a single reversed V-shaped
dural opening with the base towards the fo-
ramen magnum (Figure 5-8f). Arachnoid mem-
brane of the cisterna magna is often still intact

186
Figure 5-8 (c). Midline approach to fourth ventricle. See text for details.

187
at this point (Figure 5-8g). With the dura open,
also the arachnoid membrane is opened as a
flap with the base caudally and it is attached to
the caudal dural leaf with a hemoclip(s) (Figure
5-8h). This is to prevent the arachnoid mem-
brane from flapping inside the operation field
during the whole procedure. Then, under high
magnification of the microscope, the cerebellar
tonsils are gently pushed apart and the caudal
portion of the fourth ventricle can be entered.
By tilting the table forward, good visualization
of the upper parts of the fourth ventricle and
even the aqueduct can be obtained.
T&T:
• Neurosurgeon fixes the head clamp and is
in charge of the positioning all the way
• The position should allow the neurosurgeon
to rest his or her arms on patient's shoulders
• Neck is flexed forward, no rotation or
lateral tilt
• Usually one burr hole is enough, dura care-
fully detached
• There are large venous plexus at the level
of foramen magnum
• All the bleeding must be stopped even
more carefully than in other positions
• Dura is better opened under the microscope
• Perfect hemostasis throughout the proce
dure, no oozing is allowed
• Tilting the table forward allows
visualization of the cranial portion of
the IV ventricle

188
Figure 5-8 (d). Midline approach to fourth ventricle. See text for details.

189
Figure 5-8 (e). Midline approach to fourth ventricle. See text for details.

190
Figure 5-8 (f). Midline approach to fourth ventricle. See text for details.

191
Figure 5-8 (g). Midline approach to fourth ventricle. See text for details.

192
Figure 5-8 (h). Midline approach to fourth ventricle. See text for details.

193

195
This chapter introduces general strategies and
microneurosurgical techniques that are used in
Helsinki. We focus on some of the most com-
mon lesions encountered in our practice. We
will not go through indications for surgical
treatment, instead, we want to present a col-
lection of tricks and techniques that we find
useful in the actual execution of these surgical
procedures.
6.1. ANEURYSMS
For an unknown reason the rupture rate of in-
tracranial aneurysms is almost twice as high
in Finland as in other Western populations. In
Helsinki we have treated about 8,000 intrac-
ranial aneurysms during the microsurgical era
starting mid-70's. Nowadays, we annually op-
erate more than 300 patients with intracranial
aneurysms, more than half of them with rup-
tured ones. Over the last 20 years the catch-
ment area of our department has remained
very similar, about 2 million people. During
this time the number of ruptured aneurysms
has remained rather stable, but the number of
unruptured aneurysms is steadily increasing.
The easy availability of different noninvasive
imaging modalities has multiplied the number
of incidentally found aneurysms, and also the
policy for preventive treatment of these lesions
has become much more active over the years.
6.1.1. Approaches for different aneurysms
Nearly all anterior circulation aneurysms are
operated using the LSO approach (Figure 6-1).
The only exceptions are distal anterior cerebral
artery (DACA) aneurysms and distal MCA an-
eurysms. The DACA aneurysms are approached
through a paramedian interhemispheric ap-
proach whereas the distal MCA aneurysms ei-
ther through a frontotemporal craniotomy in
supine or lateral park bench position. In both
cases the neuronavigator may be helpful in
planning the approach trajectory.
For posterior circulation aneurysms we utilize
several different approaches depending on
the aneurysm location. The basilar bifurcation
aneurysms and those at the origin of the su-
perior cerebellar artery (SCA) are most often
approached using the subtemporal approach.
In case the basilar bifurcation is located much
higher than the posterior clinoid process and
the clivus (≥10 mm) we use the LSO and the
trans-Sylvian route. If on the other hand the
basilar bifurcation is much lower than the
posterior clinoid process, then the presigmoid
approach is needed. Even if one could reach
the actual aneurysm with the subtemporal ap-
proach, especially after cutting the tentorium,
the true problem in basilar bifurcation aneu-
rysms is proximal control. To get good proximal
control one often needs to make much more
extra work, but it is generally time well spent.
Especially in ruptured aneurysms, the risk of
aneurysm re-rupture during clipping is very
high and should be prevented by all possible
means. The basilar trunk and the vertebrobasi-
lar junction aneurysms at the middle third of
the clivus, are the most difficult to approach.
The presigmoid approach is often the only op-
tion and the clipping of the aneurysms is fur-
ther hampered by the perforators arising from
the basilar trunk towards the brain stem. Aneu-
rysms of the vertebrobasilar junction situated
at the lower third of the clivus, aneurysms at
the origin of the PICA or proximal PICA aneu-
rysms are best reached with a small retrosig-
moid approach as long as they are at least 10
mm above the level of foramen magnum. Those
closer to the foramen magnum require the lat
6. SPECIFIC TECHNIQUES AND STRATEGIES
FOR DIFFERENT PATHOLOGIES
Aneurysms | 6

196
Figure 6-1. Ruptured ICA bifurcation aneurysm clipped through left LSO approach.
6 | Aneurysms
eral approach with more bone removal. Finally,
distal PICA aneurysms are operated through ei-
ther the lateral approach or the posterior low
midline approach depending on the exact loca-
tion of the aneurysm.
6.1.2. General strategy for ruptured aneurysms
Our general strategy for surgery of ruptured
aneurysms is very similar irrespective of the
aneurysm location or size. Giant, partially
thrombosed, calcified and fusiform aneurysms
are special subgroups, which often need a cus-
tomized strategy with options for bypass pro-
cedures, endovascular balloon occlusions and
intraoperative DSA angiography. Fortunately,
these cases represent only about 5% of all the
aneurysms we see. In the majority of cases we
can follow a relatively standardized strategy.
The selection of microsurgical approach is
based on the aneurysm location as described
above (section 6.1.1.). The actual surgical strat-
egy for aneurysms includes the following steps:
(a) craniotomy; (b) brain relaxation by release
of CSF and possible partial removal of space
occupying ICH; (c) establishing proximal and
distal control of the parent arteries; (d) aneu-
rysm neck dissection under temporary clipping
of the arteries; (e) insertion of the pilot clip; (f)
further dissection of the aneurysm dome from

197
the surrounding structures and possible remod-
eling of the dome; (g) final clipping and check-
ing of the patency of the surrounding arteries;
(h) removal of the remaining ICH if present;
(i) application of Surgicel with papaverine lo-
cally to prevent vasospasm; and (j) wound clo-
sure. This whole strategy does not differ much
from our strategy for unruptured aneurysms.
The greatest differences are the more oede-
matous brain and the constant fear of aneu-
rysm re-rupture. Thus, in ruptured aneurysms
more time is initially spent on obtaining a slack
brain and more CSF needs to be released. One
needs to open several cisterns to remove suf-
ficient amount of CSF; for anterior circulation
aneurysms fenestration of the lamina termi-
nalis and subsequent removal of CSF directly
from the third ventricle is usually the action of
choice. Once the actual dissection towards the
aneurysm starts, proximal control needs to be
established as soon as possible, and the actual
aneurysm is better left alone before the proxi-
mal artery has been identified. The blood in the
subarachnoid space obstructs vision, makes
identification of structures more demanding,
and the actual brain tissue is more prone to
oozing. Manipulation of the vascular structures
near the aneurysm dome should be performed
only after proper proximal control has been es-
tablished. It is often wiser to leave some blood
clot behind than to chase after every small clot
piece, which would risk possible damage to the
surrounding perforators.
When operating on a ruptured aneurysm in a
patient with multiple aneurysms, we do not
perform multiple craniotomies. The ruptured
aneurysm is treated first. The additional an-
eurysms that can be easily accessed through
this same approach may be clipped during the
same session. If there are difficulties during the
clipping for the ruptured aneurysm, the un-
ruptured aneurysms are left alone and treated
several months later if appropriate. We usually
do not use contralateral approaches when op-
erating on an acute SAH patient.
6.1.3. General strategy for unruptured
aneurysms
Unruptured aneurysms, in general, are easier
to approach than their ruptured counterparts
(Figure 6-2). Again the complex, giant, par-
tially thrombosed, calcified or fusiform aneu-
rysms are exceptions. The basic steps in an-
eurysm surgery for unruptured aneurysms are
the same as for the ruptured ones (see above).
With good neuroanesthesia, the lack of space
is not a problem and even the aneurysm can
be approached more freely. In unruptured an-
eurysms it is usually sufficient to release CSF
from the actual cistern where the aneurysms is
located, i.e. opening of the lamina terminalis is
seldom required. All the anatomical structures
can be better identified and the dissection
plane is easier to maintain. Smaller opening
of the arachnoid is often sufficient and less of
the surrounding structures need to be exposed.
Intraoperative rupture can happen even in un-
ruptured aneurysms, but this is often caused
by direct manipulation of the aneurysm dome,
its tight attachment to the surrounding brain,
or a calcified aneurysm wall. We prefer to use
temporary clips even in unruptured aneurysms
as they soften the aneurysm dome and facili-
tate safer dissection and clipping of the neck.
In case of multiple aneurysms, we try to clip all
the aneurysms, which are accessible through
the same craniotomy during the same session.
Contralateral approaches can be used.
6.1.4. Release of CSF and removal of ICH
Release of CSF is the first and foremost step in
obtaining a relaxed brain and sufficient room
for further dissection. The whole approach
strategy has to be planned so that CSF can be
released gradually during the different steps of
the approach.
Aneurysms | 6

198
For the LSO approach, opening of the optic and
carotid cisterns is the first step. If further CSF
needs to be removed to relax the brain prop-
erly, the next choice would be to fenestrate the
lamina terminalis, unless there is a downward
projecting ACoA aneurysm. In cases where the
lamina terminalis cannot be approached, the
Liljequist's membrane can be opened in be-
tween the optic nerve and the ICA, and the
interpeduncular cistern entered for more CSF
to be released.
During the interhemispheric approach, CSF is
first released from the interhemispheric fis-
sure and the pericallosal cistern. This cistern is
relatively shallow and only a limited amount of
CSF can be released. If the brain remains tight,
there are two options: (a) to make a ventricular
puncture using a ventriculostomy catheter at
the lateral edge of the craniotomy, or (b) dislo-
cate the ipsilateral pericallosal artery laterally
5–10 mm and puncture the corpus callosum
with bipolar forceps to enter into the lateral
ventricle ("Balkenstich").
Figure 6-2. Unruptured ACoA aneurysm clipped through right LSO approach.
6 | Aneurysms

199
In the subtemporal approach the initial release
of CSF has to be obtained via a lumbar drain,
with 50–100 ml removed. Intraoperatively, ad-
ditional CSF is removed along the floor of the
middle fossa, but especially at the tentorial
edge from the interpeduncular cistern.
In the retrosigmoid approach the lumbar drain
is also implemented, but later additional CSF
is removed either from the cisterna magna by
tilting the microscope caudally, or from the
cerebello-pontine cistern.
The presigmoid approach and the lateral ap-
proach to foramen magnum both require lumbar
drain and additional CSF release from the cere-
bellopontine cistern. The prepontine cistern, and
the cisterna magna can be also approached.
In case of large ICH and lack of space, a small
cortical incision is made accordingly to the lo-
cation of the hematoma. We try to avoid elo-
quent areas such as the Broca's area. Some of
the ICH is removed via this cortical incision to
gain more space but care is taken not to cause
inadvertant aneurysm rupture as this would
be difficult to control through the ICH cavity.
While removing the ICH clot, before or after
clipping, only minor force should be applied so
as not to sever the perforating arteries. Irriga-
tion with saline helps in releasing the blood
clots from the surrounding structures. The re-
maining major part of the ICH is removed only
after the ruptured aneurysm has been secured.
Ruptured MCA bifurcation aneurysms cause
most frequently such an ICH that emergency
removal is required. In our series, as many as
44% of the ruptured MCA bifurcation aneu-
rysms had bled into the adjacent brain tissue.
In our practice, patients with massive ICHs are
transferred directly to the operating room from
emergency CT/CTA for immediate ICH removal
and clipping of the aneurysm(s). Early surgical
removal of massive ICH is believed to improve
the outcome of ruptured MCA aneurysms. The
propensity for ICH may explain the higher than
average management morbidity and mortality
in patients with ruptured MCA bifurcation an-
eurysms compared to other anterior circulation
aneurysms.
6.1.5. Dissection towards the aneurysm
With the brain relaxed, we proceed with dis-
section towards the aneurysm. In nearly all
unruptured aneurysms the distal artery is fol-
lowed in the proximal direction until the an-
eurysm is identified. For most ruptured aneu-
rysms we utilize this same strategy, but with
more emphasis on locating and controlling the
proximal parent artery as soon as possible. The
dissection starts with identification of certain
standard structures such as the cranial nerves
or bony structures. From these the arteries are
derived. In parallel running arteries such as the
pericallosal arteries or M2 and M3 segments
of the MCA, careful study of the preoperative
images for the branching patterns helps in dis-
tinguishing which artery is which. Each aneu-
rysm location has certain specific tricks, which
need to be taken into consideration. For these
we kindly refer to our numerous publications
on microneurosurgery of aneurysms at specific
locations.
In general, one should orient the dissection
along the arterial surface utilizing the natu-
ral dissection planes provided by the cisterns
in which the arteries run. The aim is to locate
the actual aneurysm, but more importantly the
proximal parent artery. All the initial steps of
the dissection are oriented towards the goal of
obtaining proximal control. Only after proximal
control has been established, the dissection
can proceed further with mobilization of the
aneurysm dome. Depending on the aneurysm
location, perforators may be found in close
vicinity to the aneurysm, or sometimes even
attached to the dome. Preserving the perfora-
tors is usually the most tedious part of the op-
eration and may require a lot of high precision
work, including multiple trials for optimal clip
Aneurysms | 6

200
position. We use high magnification during the
whole dissection along the vessels to prevent
accidental damage to all the small arterial and
venous structures. Small venous bleedings can
be tamponated with Surgicel and cottonoids,
but even the tiniest arterial bleedings should
be identified under very high magnification
and coagulated with sharp bipolar forceps.
6.1.6. Opening of the Sylvian fissure
The Sylvian fissure needs to be opened for
all MCA aneurysms, as well as some ICA an-
eurysms, namely those originating at the ICA
bifurcation and some of the aneurysms located
at the origin of the anterior choroid artery or
the posterior communicating artery. We do not
open the entire Sylvian fissure, only the portion
which is necessary for the approach, in most
cases the proximal part for the length of 10–15
mm. Factors which would require a more ex-
tensive and distal opening of the Sylvian fis-
sure for better proximal control of the M1 or
even the ICA bifurcation are: (a) ruptured an-
eurysm, (b) secondary pouch in the aneurysm
dome, (c) intertruncal or lateral projection of
the dome, and (d) involvement of branches or
the MCA bifurcation in the aneurysm. In giant
MCA aneurysms, the Sylvian fissure is opened
widely, both from the carotid cistern and distal
to the aneurysm. In most MCA aneurysms, our
strategy is to enter the Sylvian fissure and to go
from distal to proximal towards the aneurysm
(Figure 6-3). Only in some ruptured or complex
aneurysms, where proximal control might be
difficult to obtain through this route, we ini-
tially dissect the proximal M1 from the carotid
cistern side to have control before entering the
Sylvian fissure.
The best place to enter the Sylvian fissure is
usually where transparent arachnoid is present.
The venous anatomy on the surface of the Syl-
vian fissure is highly variable. Multiple large
veins often follow the course of the Sylvian fis-
sure, draining into the sphenoparietal or cav-
ernous sinuses. These veins are generally run-
ning on the temporal side of the Sylvian fissure.
In principal, we prefer to open the arachnoid
covering the Sylvian fissure on the frontal lobe
side. However, in the presence of multiple large
veins or anatomic variations the dissection
plan should be tailored accordingly. Dissection
of the Sylvian fissure is more difficult with a
swollen brain in acute SAH or with adhesions
from previous SAH or operations. Preservation
of the dissection plane is mandatory.
The entire opening of the Sylvian fissure should
be performed under very high magnification of
the microscope. First, we open a small window
in the arachnoid with a pair of jeweler forceps
or a sharp needle acting as an arachnoid knife.
Then we expand the Sylvian fissure by injecting
saline using a handheld syringe, i.e., the wa-
ter dissection technique of Toth (see section
4.9.10). The idea is to get relatively deep into
the Sylvian fissure, and to enter the Sylvian cis-
tern from this small arachnoid opening. There
are two arachnoid membranes that need to be
opened, a superficial one covering the cortex
and a deeper one inside the fissure limiting the
Sylvian cistern. Once inside the Sylvian cistern,
the dissection proceeds proximally by gently
spreading the fissure in an inside-out manner.
In our experience, this technique allows easier
identification of the proper dissection plane.
Bipolar forceps and suction act both as dissec-
tion instruments and delicate microretractors.
Cottonoids applied at the edges of the dissect-
ed space act as soft retractors, and pressure
applied gently on the both walls of the fissure
will stretch the overlying bridging tissues, fa-
cilitating their sharp dissection. All arachnoid
attachments and strands are cut with micro-
scissors, which can also act as a dissector when
the tips are closed. In order to preserve larger
veins, some small bridging veins may have to
be coagulated and cut. However, most vascular
structures can be found to belong to either side
of the Sylvian fissure, and can be mobilized
without the need of transsection.
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201
Inside the Sylvian cistern, the M3 and M2 seg-
ments of the MCA are identified and followed
proximally. The M2s should be covered by
the intermediate Sylvian membrane, another
arachnoid membrane, which in some patients
can be rather prominent in others hardly even
identifiable. By following the M2s proximal-
ly, one should arrive at the MCA bifurcation
where the most difficult task is to identify the
proximal MCA trunk (M1) for proximal control.
In the surgical view the M1 is often hidden by
the bifurcation and its course is often along the
visual axis of the microscope making its iden-
tification quite difficult during the initial dis-
section. The M2 trunk with a medial course is
easily confused with the M1 unless one keeps
this in mind. The M1 can be often more easily
reached from behind and below the bifurcation
than in front and above. A more distal opening
of the Sylvian fissure provides better angle to
visualize and obtain control of the M1 just be-
neath the bifurcation. If needed, the dissection
continues proximally along the M1 trunk in the
deepest and often the narrowest part of the
proximal Sylvian fissure. Care is needed not to
severe the lateral lenticulostriate arteries dur-
ing the different stages of the dissection. Nu-
merous arachnoid trabeculations around the
proximal M1 trunk make dissection demand-
ing, and we advocate sharp dissection.
6.1.7. Temporary clipping
Usually, it is not advisable to dissect the dome
completely free before applying the so-called
'pilot' clip. Instead, the arteries around and ad-
jacent to the base should be dissected free and
the base cleared thoroughly (Figure 6-4). Fre-
quent use of temporary clips allows for a safe
and sharp dissection of the aneurysm and the
adjacent arteries. The duration of each tempo-
rary occlusion should be kept as short as pos-
sible (max 5 minutes) (Figure 6-5). In elderly
Figure 6-3. MCA bifurcation aneurysm clipped through right LSO approach.
Aneurysms | 6

202
patients and those with very atherosclerotic
arteries, temporary clipping should be used
more sparingly. Curved temporary clips may be
more suitable for proximal control and straight
ones for distal control. Dissection and prepa-
ration of sites for temporary clips should be
performed with bipolar forceps with blunt tips
or with a microdissector. The proximal clip can
be close to the aneurysm, but the distal ones
should be at a distance so as not to interfere
with the visualization and permanent clipping
of the aneurysm neck. It is practical to gen-
tly press the temporary clip down with a small
cottonoid to protect it from the dissecting in-
struments. Temporary clips should be removed
in distal to proximal order. When removing the
temporary clips, they are first opened in place
to test for unwanted bleeding from the poten-
tially incompletely clipped aneurysm. Removal
in rush can be followed by heavy bleeding and
great difficulties in placing the clip back. While
removing the temporary clips, even the slight-
est resistance should be noted as possible in-
volvement of a small branch or a perforating
artery in the clip or its applier.
We do not use electrophysiologic monitoring
during temporary clipping or aneurysm surgery
in general. Unlike in tumor surgery, we do not
find much benefit provided by the present neu-
Figure 6-4. With a pilot clip on, the adjacent perforators are dissected free.
6 | Aneurysms

203
rophysiologic monitoring in aneurysm or AVM
surgery. The temporary clips are used only when
truly required, and they are kept in place out of
necessity and for as short time as possible. So
even if we had some indication during tempo-
rary clipping that certain evoked potentials are
dropping, this would not change our action at
that moment of time. The aneurysm would still
have to be occluded, or the artery repaired, be-
fore the temporary clips can be removed.
6.1.8. Final clipping and clip selection
A proper selection of clips with different shapes
and lengths of blades, and applicators, suit-
ing the imaged aneurysm anatomy, should be
ready for use. The optimal final clip closes the
whole base but prevents kinking or occlusion of
the adjacent branches (Figure 6-6). Usually the
smallest possible clip should be selected. Unless
dome re-modeling is used, the blade of a single
occluding clip should be 1.5 times the width of
the base as suggested by Drake. Frequent short-
term application of temporary clips during the
placement and replacement of aneurysm clips
is routine in our practice. We prefer inserting
first a pilot clip over the aneurysm dome, often
preferring Sugita clips for their wide opening
and blunt tips. The pilot clip is later exchanged
for a smaller and lighter final clip. As the clip
is slowly closed, the surrounding arteries and
perforators are inspected for kinking, twisting
and compromised flow. Adequate dissection,
proper sizes of clips and careful checking that
the clip blades are well placed up to their tips
are required to preserve the adjacent branches
(Figure 6-7). We use multiple clipping, two or
more clips, for wide-based, large and often cal-
cified thick-walled aneurysms (Figure 6-8). In
these, one should always leave some base to
prevent occlusion of the parent artery by the
clip. After the clipping, the dome of the an-
eurysm may be punctured and collapsed (Fig-
ure 6-9). It is important to inspect the tips of
the clip on both sides to make sure that they
have not caught any branches or any of the
perforators. The clip blades should completely
close the base of the aneurysm. Because the
arteries may become kinked or occluded af-
ter removal of the retractors, the flow should
be checked once more and papaverin applied.
When appropriate, not risking the surrounding
branches, we resect the aneurysm dome for the
final check of closure and for research purposes
(Figure 6-9). This policy teaches one to dissect
aneurysm domes more completely and thereby
avoid closure of branching arteries. Opening of
the aneurysm facilitates effective clipping by
reducing intraluminal pressure and should be
used in strong-walled, large, and giant aneu-
rysms.
6.1.9. Intraoperative rupture
The aneurysm may rupture during any stage of
the dissection or clipping. The risk of rupture
is highest for the aneurysms attached to the
surrounding brain or especially the dura, where
extensive manipulation and retraction of the
surrounding structures may stretch the dome
and cause intraoperative rupture of the aneu-
rysm. This is why excessive retraction should be
avoided during dissection. In case of rupture,
control should be first attempted via suction
and compression of the bleeding site with cot-
tonoids. One should not try to clip the aneu-
rysm in haste directly as this could easily end
up in tearing the aneurysm base or even the
Figure 6-5. Stop watches are used to time the
temporary occlusion, for each clip separately.
Aneurysms | 6

204
Figure 6-6.
Figure 6-7.
6 | Aneurysms

205
Figure 6-6. Proper size clip prevents kinking or accidental occlusion of perforators.
Figure 6-7. Meticulous checking to make sure that all perforators are outside the clip blades.
Figure 6-8. Multiple clips can be used in thick-walled aneurysms.
Figure 6-9. Collapsing the aneurysm dome enables viewing around the whole aneurysm dome.
Figure 6-9.
Figure 6-8.
Aneurysms | 6

206
parent artery. Instead, the aneurysm should
be isolated with temporary clips applied both
proximally and distally. With the bleeding un-
der control, the aneurysm base is dissected free
and the pilot clip applied. Short and sudden
hypotension by cardiac arrest, induced by in-
travenous adenosine, can be used to facilitate
quick dissection and application of a pilot clip
in case of uncontrolled bleeding (see below). A
small and thin walled aneurysm may rupture
at its neck during dissection. Under temporary
clipping of arteries, reconstruction of the base
by involving a part of the parent artery in the
clip should be attempted. One option, hindered
often by the deep location, is to suture the rup-
ture site with 8/0 or 9/0 running sutures or to
repair the site using anastoclips, followed by
clipping and reinforced with glue.
6.1.10. Adenosine
In recent years we have used intravenous ad-
enosine to achieve a short-lasting cardiac ar-
rest. To induce cardiac arrest, the anesthesiolo-
gist injects 20 – 25 mg of adenosine as a rapid
bolus into a large vein, preferably into the cen-
tral venous line, with flush. Injection of adeno-
sine is followed by an approximately 10-second
cardiac arrest (see also section 3.9.2). Differ-
ent patients seem to react differently to the
drug and in some patients actual cardiac ar-
rest is not observed. But more important than
the cardiac arrest is a short-lasting, significant
hypotension, with systolic blood pressure drop-
ping below 50 mmHg. This is observed even in
those patients who maintain normal cardiac
rhythm throughout the action of the drug. If the
useofadenosineisanticipated,thencardiacpads
are placed on the chest of the patient in case of
need for cardioversion. In our experience of more
than 40 cases, they have not been needed so far.
We use adenosine in essentially two differ-
ent scenarios. The first one is intraoperative
rupture, which is difficult to control by other
means. The short cardiac arrest and hypotension
allows the neurosurgeon to suck all the blood
from the operative field and place a pilot clip at
the rupture site. With the bleeding under con-
trol, the operation continues with the pilot clip
being replaced later by a better-planned, final
clip. An experienced neurosurgeon can often
see from the preoperative images which kind of
aneurysm is prone to rupture prematurely and
have the adenosine ready beforehand.
The other situation for use of adenosine is in
complex aneurysms, where proximal control is
difficult or impossible to obtain using the nor-
mal means of placing a temporary clip. In such
a situation, the short cardiac arrest and hypo-
tension makes the aneurysm dome soft and
malleable so that the pilot clip can be intro-
duced over the neck without the risk of tear-
ing the aneurysm. The soft dome allows ma-
nipulation and proper visualization of the neck,
which can otherwise be completely obstructed
by the strong and large pulsating mass of the
aneurysm.
Irrespective of the indication, the use of ad-
enosine always requires seamless co-operation
between the whole OR team. The neurosurgeon
is the one to requests its use, but the anesthesi-
ologist should not give the drug until the scrub
nurse has all the necessary clips prepared and
the neurosurgeon has his or her instruments in
position. After the adenosine injection the an-
esthesiologist starts counting aloud the systo-
lic blood pressure every one or two seconds.
When the blood pressure starts to drop, the
neurosurgeon and the scrub nurse know that
the time has come for them to execute their
pre-planned actions.
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207
6.2. ARTERIOVENOUS MALFORMATIONS
The microsurgical removal of a complex AVM
remains one of the most difficult tasks in
present day microneurosurgery. Unlike in tu-
mor surgery, incomplete removal is likely to
lead to death or disability. The most challeng-
ing aspects of caring for a patient harboring
an AVM is to decide rationally upon the man-
agement strategy. A rough estimate for the
patient is that the risk percentage to have a
fatal bleeding from an untreated AVM during
the remaining lifetime is (90 - age in years)%.
The best and most definitive treatment of cer-
ebral AVMs is still the complete microsurgical
removal in experienced hands.
6.2.1. General strategy in AVM surgery
Every AVM is different, not only due to its lo-
cation but also to its angioarchitecture. Care-
ful evaluation of preoperative angiograms is
in AVM surgery even more important then in
aneurysm surgery. Due to the high variability
between different AVMs, it is impossible to give
general advice on how all of them should be
operated on. But there are certain basic con-
cepts that are employed and the final decision
on the strategy is made on a case-by-case ba-
sis. Our microneurosurgical strategy in AVM
surgery consists of the following main compo-
nents: (a) accurate preoperative embolization;
(b) selection of the optimal surgical approach;
(c) identification and preservation of the nor-
mal passing-through arteries; (d) temporary
clipping of feeding arteries; (e) coagulation of
the small, deep feeders inside the normal brain
surrounding the AVM ("dirty coagulation"); (f)
preservation of the draining vein until the last
phase; (g) complete removal of the AVM; (h)
meticulous hemostasis; (i) intra- and postop-
erative DSA; and (j) clinical and radiological
follow-up. In addition there are several other
small details, which have been observed by us
and others over the years. All these steps are
explained in more detail below.
There are two very important aspects regarding
AVM surgery compared to e.g. tumor surgery:
(1) the aim should always be the complete re-
moval of the AVM since partial removal is of no
benefit to the patient; and (2) during micro-
surgical removal the AVM should be removed
in one piece, since internal decompression or
piecemeal excision is not possible as it would
only cause very heavy bleeding from the nidus.
We do not recommend staged operations for
AVMs as they significantly increase the rupture
risk while waiting for the consecutive proce-
dures. In addition, the anatomy becomes dis-
turbed making any further surgical attempts
even more difficult than the first one. One
should be aware that once started, the AVM
surgery must be carried all the way to the end.
T&T:
• You can not "try" AVM surgery, you must
know you can do it!
• You need to have an attitude of a tiger, a
samurai, a fighter, or whoever who is 110%
sure of winning!
6.2.2. Preoperative embolization
Large AVMs can be often reduced in size with
preoperative embolization. The feeders and the
actual nidus can be occluded or reduced by en-
dovascular means. The commonly used materi-
als are glue and more recently Onyx. With glue
the total obliteration of the nidus was uncom-
mon, but nowadays with the use of Onyx, up
to 50% of the selected cases can be occluded
completely. Although the complete occlusion
is often the aim, even partial occlusion can be
Arteriovenous malformations | 6

208
helpful from the surgical point of view. Preop-
erative Onyx embolization has revolutionalized
the treatment of AVMs, as many of them, after
extensive filling with Onyx, can be removed or
isolated from the circulation with much less
difficulties than in their native state. How-
ever, poorly performed endovascular occlusion
can be of more harm to microsurgical removal
than of benefit. Each case should be evaluated
by both interventionalists and neurosurgeons
before the final treatment strategy is decided.
Partial embolization alone, according to our
follow-up, increases the risk of rebleeding al-
most threefold, and should be used only when
followed by radio- or microsurgery.
Embolization is very useful in obliterating the
deep feeders of the AVM, those that are difficult
to reach with microsurgery, making surgical re-
moval more feasible. Unfortunately, the deep-
est, the smallest and the most tortuous vessels
can only seldom be reached and embolized to
produce any real benefit for the surgery.
There are differences among the different em-
bolic agents from the microsurgical point of
view. Precipitated glue is a hard, brittle, and
crystal-like substance, which is unmalleable
and extremely difficult to cut. Onyx on the other
hand is a softer, silicone-like material that can
be easily cut with microscissors. There is one
problem related to all the embolic substances.
If a dilated vascular structure such as an intra-
nidal aneurysm is filled with it, then it cannot
be compressed or reduced in size with bipo-
lar coagulation. Also, if there is some bleeding
in between the embolic agent and the vessel
wall, this cannot be sealed off by coagulation
and such bleeding is actually very difficult to
handle. But in general, due to the use of Onyx,
intraoperative bleeding during AVM surgery
has diminished a lot and the surgery resembles
more that of extrinsic tumor surgery.
Timing of preoperative embolization is impor-
tant. With Onyx, a large portion of the AVM
is often occluded during one embolization ses-
sion. In our experience this has resulted in sev-
eral very serious post-embolization bleedings of
the AVM. They usually take place several days
after the procedure, while the patient is wait-
ing for scheduled surgery. The reason probably
is a rapid change of the hemodynamic condi-
tions inside the nidus. For this reason, lately,
we have tried to perform both the embolization
and the microsurgical removal without unnec-
essary delays, usually on the same day or on
consecutive days.
6.2.3. Approaches
Operations for AVMs are performed under
moderate hypotension. The head is signifi-
cantly elevated above the heart level repre-
senting almost a semi-sitting position. A true
sitting position is seldom used, only when truly
required, such as in some midline posterior
fossa AVMs. Lateral posterior fossa AVMs are
operated in park bench position, as are many
of the more posterior temporally, parietally and
occipitally located AVMs. A modern, mobile op-
erating microscope is of special importance. In
fact, based on our experience, no AVM should
be operated on without a microscope. Moving
fluently around the AVM using the mouthpiece
control of the microscope markedly reduces op-
erating time. In microneurosurgery in general,
our trend has been towards rather small bone
flaps. However, in AVM surgery, especially in
cortical ones, we often use larger craniotomies
to obtain better orientation towards the AVM
and its surroundings. In deep-located AVMs the
keyhole principle, however, is still applied.
6.2.4. Dural opening and initial dissection
After the craniotomy, the dura is carefully in-
spected under the operating microscope be-
cause many draining veins, and also the AVM
itself, can be firmly adherent to the dura. Ad-
herence is especially common in redo-cases
and after severe or several bleedings and/or
6 | Arteriovenous malformations

209
embolizations. With the dura opened, we first
try to locate the feeding arteries. These can be
visualized well in superficial AVMs by using
intraoperative ICG videoangiography (Figure
6-10). The dynamic flow of the contrast inside
the vessels allows for distinguishing between
the arteries and the arterialized veins, which
with the nidus still patent, have almost the
same color under normal light.
The main draining veins are identified. They
should be preserved until the very last steps of
the AVM removal. AVMs with only one drain-
ing vein are usually more difficult to remove,
as this single vein has to be preserved at all
costs all the time. Premature occlusion of the
sole draining vein can result in uncontrollable
intraoperative AVM rupture and catastrophic
results, especially in large or medium sized
AVMs.
Sometimes the draining vein runs inside the
bone and can be accidentally damaged already
while removing the bone flap. This leads easily
to catastrophic bleeding. One possible trick in
such a situation is first to compress the bleed-
ing site in the dura with a cottonoid and then
to suture this cottonoid circumferentially to the
surrounding dura to seal the bleeding until the
final stage of the AVM removal. In situations
with damage to the single draining vein and
rapid swelling of the AVM, a fast and targeted
removal of the lesion is often the only option.
The task may become little easier, if there is
an experienced assistant at hand to allow four-
handed removal of the AVM. Infrequently, in
some small AVMs, the draining vein can be cut
on purpose during early steps of the removal,
and this draining vein can be used as a sort of
handle to help the dissection.
Figure 6-10. ICG videoangiofraphy shows different stages of arterial and venous filling in a superficial AVM.

210
T&T:
• Careful analysis of the angioarchitecture of
the whole AVM should be carried out once
the proper visual contact with the AVM has
been established.
• The draining veins must be respected and
preferably left intact until the final step of
the removal
• In the beginning of the operation, a lot of
time should be spent on careful dissection
and identification of all the vessels in the
vicinity of the AVM. This time pays back, as
with clear anatomical understanding of the
vascular relationships, the removal of even
a complex looking AVM is possible.
6.2.5. Further dissection and use of
temporary clips
The borderline between the AVM and the sur-
rounding brain is generally grayish and has
some glial scarring, especially in previously
ruptured AVMs. Following embolization, small
infarctions often surround the nidus. This soft,
macerated tissue can be easily removed with
suction for better visualization of the vascular
structures. Often, the hematoma has already
dissected the nidus from the surrounding brain,
so that the AVM is easier to find and remove.
Signs of past bleeding are found even in cases
without any previous clinical evidence of rup-
ture. In these cases the bleeding may have been
misdiagnosed as an epileptic seizure.
Identification of the cleavage plane between
the AVM and the brain is very helpful while
removing these lesions. Although some au-
thors prefer the technique of removing the
AVM together with substantial amount of the
surrounding brain tissue - they feel that the
procedure is safer in this way as one does not
get into contact with the nidus - our technique
is to proceed along the cleavage plane delin-
eating the nidus from the surrounding brain.
Although initially a more tedious technique, its
greatest advantages are: (a) better orientation
towards the different vascular structures, (b)
targeted removal of only the AVM nidus, and
(c) better identification of the passing-through
arteries. This last point is especially important
in AVMs located close to eloquent areas. Care-
ful opening of the arachnoid planes with a
sharp needle, jeweller's forceps and sharp mi-
croscissors, together with water dissection and
small cottonoids, allows to delineate the nidus
sharply and identify both the feeders as well as
the draining veins. It is of utmost importance
to understand where the borderline of the nid-
us is at all times, as accidental entering into
the actual nidus is always followed by heavy
bleeding. Already Olivecrona, and later many
others such as Drake, Peerless and Yaşargil,
have described that AVM surgery should pro-
ceed circumferentially around the whole AVM,
while simultaneously coagulating all the small
feeders. In Finnish there is a saying which de-
scribes this kind of behaviour as "a cat circling
around a hot pot of porridge".
The initial inspection of the AVM is performed
under less magnification, as this helps to un-
derstand the estimated borders of the nidus
and to orientate oneself to the surrounding
structures. Once that is done, the actual dis-
section of the AVM is performed under high
magnification to facilitate better identification
and handling of all the tiny feeders. The large
feeding arteries are identified first. These are
usually the easiest to handle both by preop-
erative embolization but also during surgery.
We usually put temporary clips on these large
feeders during the initial steps of the dissec-
tion. Later on, once the nidus has been deline-
ated more and it is obvious that these particu-
lar vessels are terminal feeding branches not
passing-through arteries, they are coagulated
and cut. The duration of temporary clipping is
monitored. Considering how long the tempo-
rary clips are usually in place, even up to sever-
al hours, surprisingly little or no adverse effects
are seen postoperatively. This is probably due to
a long-term adaptation of the collateral circu-

211
lation to the "vascular steal effect" caused by
the fistulous nature of the AVM. We usually do
not use permanent clips to seal small or larger
arteries or veins. Instead, after initial coagu-
lation and division, the vessel ends are sealed
once again with bipolar coagulation. It is our
long-term experience that with many small
bleeding sites the number of clips starts to ac-
cumulate and the clips are often accidentally
displaced leading to further bleeding. Excep-
tions of this are situations, where a relatively
large feeder or draining vein was accidentally
severed during early steps of the dissection. In
such a situation, we place a vascular clip onto
the distal end of the vessel next to the nidus.
This clip helps in intraoperative orientation and
it can be also used as a handle to manipulate
the nidus. In addition, we can also connect a
suture to the clip, which permits careful ap-
plication of little tension onto the nidus during
its excision from the surrounding brain.
6.2.6. Coagulation and dissection of
small feeders
The tiniest feeders of the AVM are always the
most difficult to handle. As mentioned earlier,
preoperative embolization is of great help for
microsurgery as it can occlude large portions of
the nidus and the large feeders. But it usually
does not help in occluding the tiny feeders as
these cannot be approached via the endovas-
cular route. Hemostasis of the small and thin-
walled fragile feeders close to the deepest por-
tions of the AVM is the most cumbersome part
of any AVM operation. The bleeding is difficult
to control, as these vessels have virtually no
wall for coagulation to be effective. They often
burst and retract back into the white matter
at which point they have to be chased deeper
and deeper with coagulation until the bleed-
ing stops. There is no possibility to tamponade
these bleedings, as they are profuse and mul-
tiple. They start again immediately once the
tamponade has been removed. The bleeding
sites are difficult to locate so we strongly rec-
ommend using very high magnification during
this step of the operation.
Earlier, as the last resort, we clipped these feed-
ers with special microclips, and, indeed, in some
cases after the use of many clips the bleeding
stopped. But the accumulation of clips in the
operative area became a problem. The clips
were often accidentally displaced, resulting in
further bleeding. Instead, we started to use the
"dirty coagulation" technique. The idea is to
surround the bleeding vessel with a little bit of
brain tissue and to coagulate the brain tissue
together with the vessel instead of coagulating
the vessel alone, hence the name dirty coagu-
lation. We use blunt bipolar forceps and rela-
tively low setting on the bipolar (20–25 on our
Malis device). The forceps must be clean and
cold to prevent sticking. Sharp forceps stick to
the brain more easily, which is why dirty co-
agulation is easier to execute with blunt for-
ceps. Interchanging several forceps speeds up
the operation. The whole bleeding area must be
meticulously and systematically covered with
dirty coagulation for all the bleedings to stop.
This a very time consuming part of the opera-
tion, but one should be patient, as hurrying
usually only aggravates the bleeding.
In case of a more serious bleeding, the whole
team is immediately alarmed. The blood pres-
sure is lowered even below 100 mmHg systo-
lic (sometimes as low as 70 mmHg for a short
period), the suction is often exchanged to a
slightly larger diameter, and the bleeding sites
are identified. As an emergency measure each
bleeding site is first tamponaded with cottonoid
and then followed by dirty coagulation as the
permanent solution to the situation. In general,
we prefer to take care of the bleeding imme-
diately before proceeding further. Seldom, the
bleeding site is packed and tamponated with
hemostatic agent and a new working site is
sought for, returning to the bleeding site later.
The problem with this strategy is accumulation
of cottonoids at the tamponation sites. These
cottonoids may prevent access to the remain-

212
ing parts of the AVM and their careless remov-
al provokes the bleeding again. When several
bleedings start to occur, the AVM should be
excised without further delays. In large AVMs
the final stages of the excision are the most
difficult ones. In prolonged operations the psy-
chomotor weakness occurs easily, and small er-
rors are made, often resulting in bleeding.
6.2.7. Final stage of AVM removal
The last step before the removal of the whole
AVM is coagulation and cutting of the last
draining vein. At this stage the draining vein
should already be dark or blue-colored as op-
posed to the red color and filling with arterial
blood at the beginning of the operation. If the
color has not changed, then it usually means
that there is still some part of the AVM left. In
such a situation, with good control over most
of the AVM nidus, we place a temporary clip on
the remaining draining vein. This temporarily
increases the intranidal pressure and the re-
maining portion of the nidus may be identified
by swelling. Besides the change in color of the
draining vein, the devascularized nidus should
be soft and malleable except for the parts filled
with embolic material. A hard nidus usually
means that some feeders are still left.
ICG can be of help during the final stages of
the operation. Unlike at beginning of the sur-
gery, the draining vein should no longer be fill-
ing prematurely. Actually, due to the relatively
large diameter of the veins, the contrast medi-
um often flows sluggishly and may even stag-
nate in place. Premature filling of the draining
vein indicates AVM residual.
As the total removal of a complex AVM in-
volves many operative steps, we prefer to oper-
ate at a brisk pace before fatigue sets in. The
only exception is the initial careful and time
consuming stage of studying the intraoperative
anatomy. Operations of some large AVMs with
myriads of feeders may last up to 8 hours, but
with experience ordinary AVMs can be removed
in 2 to 4 hours.
T&T:
At the beginning of a large AVM operation one
often feels like the world's best neurosurgeon.
This feeling changes rapidly into being the
world's worst neurosurgeon, as soon as the
ultra-small feeders of the deepest portion of
the AVM start to bleed! This describes well
how difficult and frustrating it is to control
these deep feeders.
6.2.8. Final hemostasis
After removal of the AVM we systematically
inspect the whole resection cavity by touch-
ing the surface gently with bipolar forceps and
small cottonoids. If bleeding occurs, it usually
means that a small remnant of the AVM has
been left behind. The area is inspected and all
the bleedings are coagulated until there is no
more indication of residual AVM. Finally, the
surface of the resection cavity is covered with
fibrin glue and Surgicel, which is pressed on
the fresh glue all around the cavity.
6.2.9. Postoperative care and imaging
In complex AVMs we frequently use intraoper-
ative DSA. This is both for orientation purposes
as well as to localize remaining parts of the
filling nidus. The postoperative DSA is usually
performed in nearly all AVM patients during the
same anesthesia before transportation to the
neurosurgical ICU. Patients with straightfor-
ward small and medium-sized AVMs are woken
up in the ICU over a period several hours fol-
lowing the surgery. They are kept normotensive,
and discharged to a neurosurgical bed ward on
the next day. Patients with complex or large

213
AVMs, especially those with myriads of small
deep feeders that required heavy use of dirty
coagulation intraoperatively, are usually kept
in controlled moderate arterial hypotension
(systolic 100–120 mmHg) for several days. This
may also mean prolonged sedation. In some
cases with very complex AVMs, we even use
deep hypotension and deep sedation for several
days. Despite the initial excellent postoperative
CT images, we have seen a large postoperative
hematoma occurring as late as one week after
the operation. This has happened several times
in patients with many tiny deep feeders. After
introducing dirty coagulation, postoperative
hematomas have been less frequent. In addi-
tion to hypotension, prevention of seizures is
routine.

214
6.3. CAVERNOMAS
The two most common symptoms of brain cav-
ernomas are seizures or hemorrhages. Recently,
with the wide availability of MRI imaging, the
number of asymptomatic, incidental caverno-
mas has been increasing rapidly. Patients with
cavernomas fall into two groups, those with a
single lesion and those with multiple caverno-
mas. Deciding on whether to operate in a par-
ticular case is not always straightforward. In
situations where there is a single, symptomatic
lesion the decision is rather simple. These are
usually clear-cut cases and microsurgical re-
moval is often beneficial. In patients with mul-
tiple cavernomas or asymptomatic ones the
decision has to be made on a case-by-case ba-
sis after careful consideration of both the pros
and cons of the treatment.
6.3.1. General strategy in cavernoma surgery
From the microsurgical point of view, caver-
nomas are rather easy lesions to remove. They
are clearly defined, they can be excised com-
pletely from the surrounding tissue and they
do not bleed much during removal. However, at
the same time, cavernomas are also one of the
most demanding lesions to remove, especially
if located near or in eloquent areas, brainstem
or medulla. The most frustrating part of any
cavernoma operation is to locate the lesion.
Most cavernomas are small in diameter (less
than 2 cm) and they are located somewhere
inside the brain tissue. Only seldom the caver-
noma is located superficially so that it can be
seen directly at the cortical surface.
The greatest challenges in cavernoma surgery
are: (a) to localize the lesion, and (b) not to
damage the surrounding structures during re-
moval. The whole microsurgical removal of the
cavernoma should be planned to maximize the
chances of success for finding the lesion. The
optimal approach is the key. Without care-
ful planning, one may spend hours and hours
searching for this small lesion somewhere
inside the white matter with no anatomical
landmarks to guide to the target. Meanwhile,
some of the important white matter tracts or
eloquent areas may be irreversibly harmed.
Even few millimeters of brain tissue prevents
a cavernoma to be seen from the surface. Once
the lesion is located, the rest of the procedure
is relatively straightforward, but still requires
proper microsurgical technique to minimize
unnecessary manipulation of the surrounding
tissue. If possible, we try to remove caverno-
mas in one piece, but unlike AVMs, piecemeal
removal is also possible, as cavernomas usu-
ally do not bleed profusely. Piecemeal removal
is especially recommended in brain stem and
other deep-located cavernomas.
6.3.2. Intraoperative localization
There are essentially two main techniques how
cavernomas can be localized. One option is to
rely on anatomical landmarks, the other is to
use the neuronavigator or some other coor-
dinate system device and possibly ultrasound.
We usually combine the two techniques. Ana-
tomical landmarks are useful as long as the
lesion is located close to some relatively well
defined anatomical structure such as a cranial
nerve, arterial branching site, or if the lesion
is so superficial that it can be seen at the sur-
face of the brain or in the ventricle at a defined
area. The cavernoma itself is often darkish and
its consistency is somewhat harder than that
of the surrounding brain tissue. It may or may
not be surrounded by small ICH cavity; large
hematomas caused by cavernomas are rare.
The brain tissue surrounding the cavernoma is
generally yellowish, due to hemosiderin stain-
ing. In superficial lesions it is often the discol-
oration of the brain surface at a certain area,
which is indicative of the cavernoma.
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215
Anatomical structures, which are easiest to
utilize in localizing cavernomas are arteries
and their branching patterns. Cavernomas lo-
cated close to the medial surface of the frontal
lobe or those close to the Sylvian fissure can be
often localized based on the course of the ACA
or the MCA. Localization of brain stem cavern-
omas relies more on the origin of cranial nerves
than on vascular structures. Location close to
one of the ventricles may be of help, but only
when this particular region of the ventricle is
along some standard approach (e.g. intehe-
mispheric approach and callosotomy into the
lateral ventricle) that one has sufficient expe-
rience with. Otherwise, it may be difficult to
even get into the ventricle, let alone find the
cavernoma.
Nowadays, we routinely use neuronavigator
in cavernoma surgery. It may be an adjunct to
the anatomical landmarks, or, as often is the
case, the only method on which to rely while
searching for the cavernoma somewhere deep
inside the white matter. We always take both
T1 and T2 weighted MRI images, the former are
used for image registration purposes, the latter
show the cavernoma better. With the neuron-
avigator, one has to be both familiar with the
device itself, but more importantly, aware of its
limitations. Planning of the approach, check-
ing the appropriate angle of the microscope
and even the use of ultrasound to verify the
findings should be performed several times be-
fore opening the dura. Once the dura has been
opened and CSF released, the accuracy of the
device becomes much worse due to brain shift.
At this point, it is often safer to trust meas-
urements with a ruler than the neuronavigator,
which gives only a false feeling of safety.
Intraoperative ultrasound, as nice as it may
sound, is often of much less help than expect-
ed. For someone unaccustomed to interpreting
ultrasound images, it is difficult to navigate
based on this information. In skilled and experi-
enced hands it may be of true value, especially
if the device has a small ultrasound probe. But
in our experience, ultrasound is of less value
than careful preoperative trajectory planning
and the use of neuronavigator.
What if everything fails, and despite all the
possible precautions one still cannot find the
cavernoma? In such a situation, we prefer to
leave a small vascular clip as a mark along the
approach trajectory and back off. The patient
is woken up and MRI images are taken either
on the same or the next day. In most cases the
clip is found frustratingly close to the caverno-
ma, usually 5 mm or less. In the re-do surgery,
performed within a few days, the cavernoma
is then localized with respect to the clip and
removed. Although this technique necessitates
two surgical sessions, in the end it is safer for
the patient than an extensive and possibly
harmful search for the lesion during the first
session.
6.3.3. Approaches
The approach is always selected according to
the exact location of the cavernoma. The inter-
hemispheric approach is used for cavernomas
close to the interhemispheric fissure, the LSO
for those where opening of the Sylvian fissure
is needed and the retrosigmoid, subtemporal,
lateral foramen magnum or sitting position
approaches for brainstem cavernomas. Most
of the brainstem cavernomas are very close to
the surface somewhere along the brainstem.
This is usually the place that we select as the
planned point of entry and the actual approach
is then planned accordingly to provide maxi-
mal exposure of this area. When the approach
is based mainly on anatomical landmarks, the
craniotomy and dural opening are executed in
a similar fashion as for any other type of le-
Cavernomas | 6

216
sion approached in this manner. The exposure
should be sufficiently wide to allow unhindered
dissection along the natural planes. The brain
is relaxed by the release of CSF. The aim is to
arrive at the expected site of the cavernoma,
hopefully identifiable by the discoloration of
the brain tissue, along a natural route. Only
once there, the brain parenchyma is entered.
In the vast majority of supratentorial and cer-
ebellar cavernomas the anatomical landmarks
cannot be well utilized, and we have to rely on
the neuronavigator. The approach is selected to
provide the shortest possible route to the cav-
ernoma while avoiding the eloquent areas. We
prefer either supine, semi-sitting or lateral park
bench position. In prone position the use of the
neuronavigator is generally more demanding.
Contrary to the strategy applied when using
anatomical landmarks, with the neuronavigator
we try to minimize CSF release and brain shift.
We also enter the brain tissue directly just be-
neath the dural opening. It is possible to follow
natural planes such as a certain sulci, but as
the sulci may be curving into a wrong direc-
tion, one might end up with a wrong approach
trajectory. The craniotomy does not have to be
large, 2–3 cm is often enough. Before opening
the dura, the exact trajectory towards the le-
sion is checked several times. It is very helpful,
if bipolar forceps, those used for dissection, can
be fitted with neuronavigator markers. They
are easier to handle than the often long and
cumbersome pointer. Only small dural open-
ing suffices, a curved 1 cm incision is often
enough. Care is taken to release as little CSF at
this point as possible. The cortex is incised and
the brain parenchyma is entered along the line
suggested by the neuronavigator. The angle of
the microscope needs to be along the same
trajectory, otherwise one starts to accidentally
deviate from the planned trajectory.
6.3.4. Dissection and removal
The approach through the brain parenchyma
should be as gentle and short as possible. We
use very high magnification during this step.
The suction is exchanged for small bore (6 or
8) as there is only little bleeding. Every tiny
bleeding should be identified and coagulated.
We prefer to use sharp bipolar forceps. The
neuronavigator is constantly checked for the
correct approach angle, the "autopilot" option
can be utilized if available. Close to the cav-
ernoma the resistance of the brain tissue will
suddenly increase and the tissue will become
yellow and gliotic. This is a good sign, as the
cavernoma must be very close by. The yellowish
tissue is followed further until the actual cav-
ernoma is recognised by its hard consistency
and dark colour. It is usually just before find-
ing the cavernoma, that the frustration from
the whole procedure reaches its maximum.
With the cavernoma visible and the most tedi-
ous part of the surgery behind, one can relax a
little. Thin cottonoids can be inserted into the
cavity to keep it open.
The cavernoma should be circled around with
bipolar and suction. All the tiny feeders are
coagulated and the gliotic tissue surrounding
the cavernoma is removed. In brainstem cav-
ernomas we often leave the gliotic tissue be-
hind as we do not want to risk the possibility
of damaging the surrounding. There are usually
no large feeders into the cavernoma, however,
there may be a large draining, venous angioma.
General experience is, that the venous angioma
should be left intact. Coagulating it or remov-
ing it may result in postoperative venous in-
farction of the nearby area. Small cottonoids
can be used to dislocate the cavernoma and
water dissection is carefully utilized to allow
further separation of the cavernoma from the
surrounding tissue. Small ring forceps are very
helpful to pull gently on the cavernoma while
detaching it with suction. If there is hematoma
next to the cavernoma, this should be removed
6 | Cavernomas

217
along with the cavernoma. The cavernoma
can be shrinked to a certain extent with co-
agulation, but especially in larger lesions, final
piecemeal removal may be necessary.
Once the cavernoma has been removed, the
whole resection cavity is carefully inspected for
any remnants. The cavity is flushed with saline
to detect any bleedings that are coagulated. We
cover the surface of the resection cavity with
Surgicel, sometimes even with glue. Special
care is needed in cavernomas that are found
at the surface of the ventricle. In these cases
the hemostasis is even more important as there
is nearly no counterpressure, and postoperative
hematomas can happen much more easily than
in cavernomas inside the brain tissue.
6.3.5. Postoperative imaging
Postoperative MRI scans are very difficult to
interpret after cavernoma surgery. There is
nearly always some hemosiderin ring left even
after complete removal. This can be acciden-
tally interpreted as residual cavernoma even if
the whole cavernoma has been removed. For
this reason, unlike in other lesions, we tend to
trust more the neurosurgeons evaluation of the
situation at the end of the procedure than the
postoperative images. The postoperative imag-
es are mainly taken to exclude complications,
such as hematomas or infarctions.
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218
6.4. MENINGIOMAS
Meningiomas can be roughly divided into four
groups when their surgical technique is con-
sidered: (1) convexity meningiomas; (2) par-
asagittal meningiomas; (3) falx and tentorium
meningiomas; and (4) skull base meningiomas.
In addition there are some infrequent meningi-
oma locations such as e.g. intraventricular men-
ingiomas and spinal meningiomas (see section
6.9). Each of these groups has certain specific
features, which require different approach and
strategy. The common feature of all the men-
ingiomas is that over 90% of them are benign,
they usually can be removed completely, and
they have a clearly defined border. The major
vascular supply comes from the dural attach-
ment, but especially in larger tumors there can
be also feeders from the surrounding arteries.
We advocate complete tumor removal in situa-
tions where it can be performed safely without
excessive morbidity or mortality. In skull base
meningiomas with the tumor surrounding the
cranial nerves and infiltrating the cavernous si-
nus, one should be very cautious, and consider
also other options besides surgery.
6.4.1. General strategy with convexity
meningiomas
Convexity meningiomas are excellent targets
for microsurgery. The aim is to remove the whole
tumor as well as the dural origin. If possible, we
try to remove the dural origin with a 1–2 cm
margin. This means that the keyhole principle
for craniotomy cannot be applied in these le-
sions. The craniotomy should provide at least a
few centimeter margin along the borders of the
whole dural attachment. In convexity meningi-
omas that are located cranial to the insertion
of the temporal muscle, we plan a curved skin
incision that allows a vascularized, pedicled
periostal flap to be used as a dural substitute.
The local anesthetic injected along the wound
causes swelling of the subcutaneous tissues
and the periostium facilitating easier separa-
tion of the two layers. It is much easier to pre-
pare the periostal flap at the beginning of the
surgery than when the closure starts. The bone
flap is planned to allow for sufficient exposure
of the whole tumor and its attachment. Unlike
in other approaches, the dura is elevated to the
edges of the craniotomy with tack-up sutures
already at the beginning of the procedure,
before opening the dura. This prevents oozing
from the epidural space and even diminishes
the bleeding from the tumor itself.
The next step is to remove major portion of
the tumor's vascular supply coming through
the dural attachment. To do this, the dura is
cut circularly around the whole tumor with a
few centimeter margin and the dural edges are
coagulated. We prefer to use the microscope
during this step, especially if the tumor is rela-
tively close to the superior sagittal sinus in the
midline. Cutting the dura should be performed
carefully as not to sever any adjacent arteries
or veins. At the same time this step should be
done relatively briskly, because once finished,
many of the small bleedings coming from the
tumor surface will stop.
With the whole dural margin free, the ac-
tual tumor removal may proceed. The tumor
should be dissected stepwise along the dissec-
tion plane between the tumor and the cortex.
Passing-through arteries are identified and
saved, feeding arteries are coagulated and cut.
The shape of the tumor determines whether
it can be removed in one piece or in several
pieces. A conical tumor can usually be removed
in one piece, whereas a spherical tumor with
small dural attachment may require piecemeal
removal to prevent excessive manipulation of
the surrounding brain tissue. But even with the
spherical tumor, as much of the tumor should
be devascularized as possible before entering
into the tumor itself. Entering into the tumor
6 | Meningiomas

219
is often followed by bleeding and necessity
to spend a lot of time performing hemostasis,
which slows down the whole operation. So, our
strategy in convexity meningiomas is to enter
into the tumor only if necessary, for the pur-
pose of debulking it and making some extra
room for its further dissection along the bor-
derline. Otherwise we keep strictly to the dis-
section plane along the borderline and dissect
the whole tumor free from its surroundings.
Recently, we have been successful in preserv-
ing most of the cortical veins between the tu-
mor and cortex. This certainly improves rapid
recovery of the patient. The trick here is to use
very high magnification of the operating mi-
croscope. It is much easier to follow the proper
dissection plane and to distinguish between
feeders and passing-through vessels under
high magnification. Tumor removal is followed
by careful hemostasis of the whole resection
cavity and dural repair. If the bone is intact or
only slightly hyperostotic, we use a high-speed
drill to smooth the inner surface and place the
original bone flap back. In situations when
there is tumor invasion into the bone, we do
not put the original bone flap back. Instead,
we perform immediate cranioplasty with some
artificial material such as titanium mesh, hy-
droxiapatite or bone cement.
6.4.2. General strategy with parasagittal
meningiomas
Parasagittal meningiomas originate from the
cortical dura, but they are located next to the
midline, sometimes on both sides of the mid-
line. They have a special anatomic relationship
with the superior sagittal sinus and the bridg-
ing veins, often invading them. The possible in-
volvement of the venous system requires spe-
cial considerations regarding the strategy for
their removal. In general, of all the meningi-
omas located at the convexity, the parasagittal
ones are the most difficult to remove and they
carry the highest risk of postoperative venous
infarction.
There are two main problems associated with
parasagittal meningiomas: (1) how to remove
them without harming the surrounding bridg-
ing veins; and (2) what to do with the superior
sagittal sinus? Extensive involvement of the
superior sagittal sinus, its infiltration or even
occlusion due to tumor tissue must be evalu-
ated from preoperative images. Venous phase
CTA, MRA or DSA images are used to analyze
whether the superior sagittal sinus is still pat-
ent. If the superior sagittal sinus is occluded,
we may decide to remove the entire tumor to-
gether with the dural origin by extending the
dural resection to include the occluded sagittal
sinus. In these cases, the meningioma is often
bilateral. But if the superior sagittal sinus is
still patent, we prefer not to touch the sinus.
We can leave a small tumor remnant behind, at
the lateral wall of the sagittal sinus. This small
tumor remnant can be either followed conserv-
atively or treated with stereotactic irradiation
later on. The sagittal sinus may occlude com-
pletely over a longer period of time, at which
point the removal of the tumor remnant can
be planned. During the gradual occlusion of
the sagittal sinus, venous collaterals have suf-
ficient time to develop, so that venous infarc-
tions develop seldom, unlike in acute occlusion
during or immediately after surgery. In bilateral
tumors, with the superior sagittal sinus pat-
ent, we do not resect the sinus unless it is in
the anterior-most third of the sinus. Even at
this location the risk of postoperative venous
infarction exists and one should weight all the
options before carrying out the resection. Ir-
respective of the faith of the sagittal sinus, all
the bridging veins draining the surrounding
cortex should be left intact.
Meningiomas | 6

220
The skin incision and bone flap are planned to
allow for exposure of the whole tumor with
several centimeter margin along its borders.
The tumor can be either unilateral or bilat-
eral on both sides of the superior sagittal si-
nus. Even for the unilateral tumor the bone
flap should extend over the midline so that
the whole superior sagittal sinus is exposed
alongside the tumor. In the same way as with
convexity meningiomas, the dura is elevated to
the edges of the craniotomy already before the
dural incision. In unilateral tumors the medial
border towards the sagittal sinus is not elevat-
ed because of the risk of damaging a bridging
vein. The dura is opened under the microscope.
The dural incision starts lateral and proceeds
towards the midline in a curvilinear fashion
in both anterior and posterior direction. One
has to be very careful with the bridging veins,
especially close to the midline. Once the dural
incision is made, the vascular supply of the tu-
mor has been cut from all directions except the
midline. Unfortunately, midline is the direction
from which most of the vascular supply of the
tumor comes from.
The next step depends on the anatomy of the
tumor and its relation with the superior sagittal
sinus. If the tumor has its medial edge along-
side the sinus, but does not seem to infiltrate it
on preoperative images, we proceed with cut-
ting the dura along the midline, just next to the
sagittal sinus. This step has to be performed un-
der high magnification, small cut at a time. The
superior sagittal sinus opens frequently during
this step of the procedure, so to keep the situa-
tion under control, we make only a small cut at
a time. Whenever the sagittal sinus is acciden-
tally entered, the hole should be closed immedi-
ately with a suture. The suture is a more secure
way of closing the small hole than hemoclips,
which easily slide off. Coagulation with bipolar
forceps makes the hole only bigger, so we do
not recommend it. Once the dural cut has been
completed, the tumor becomes devascularized
for most part. The dissection plane between the
tumor and the cortex is then expanded with
water dissection and small cottonoids. We usu-
ally start the dissection along the lateral bor-
der and proceed in the medial direction while
cutting the arachnoid and attachments to the
vessels. It is important to note that very often
the veins draining normal cortical surface may
pass below the tumor, but there is often a clear
arachnoid plane separating them from the tu-
mor surface. Again the dissection requires pa-
tience and high magnification. Once the whole
tumor has been mobilized, it is removed, usu-
ally in one piece. With the major part of the
tumor removed, the edges of the dural opening
can be inspected for any tumor remnants. The
dural repair can be performed either with the
vascularized periostal flap or with some artifi-
cial dural substitute in the same fashion as in
convexity meningiomas.
In tumors, which infiltrate into the sagittal sinus,
or grow on both sides of the sinus, the strategy
is a little different. Once the dural flap has been
opened with the base towards the midline, the
aim is again to devascularize the tumor as much
as possible prior to its removal. One possibility
is to start to dissect the tumor away from the
cortex starting at the lateral border. With water
dissection the proper dissection plane is entered
and followed beneath the tumor medially. The
tumor can be lifted by gentle traction with a
suture attached at its dural edge. With this
strategy one is able to get very close to the mid-
line, but the problem of the possible draining
veins along or inside the medial border of the
tumor remains. It is possible to amputate the
lateral portion of the tumor to get more room
and then start careful dissection alongside the
sagittal sinus working on the intradural attach-
ment of the tumor. In case of an occluded sinus
and especially a bilateral tumor, the resection
of the sagittal sinus together with part of the
falx can be carried out once both tumor por-
tions have been otherwise detached from their
surroundings. The other possibility is to devas-
cularize the tumor by coagulating and detach-
ing it from the inner leaf of the dura along the
whole dural attachment. This leaves the tumor
6 | Meningiomas

221
in place, while the dural flap is everted over the
midline. With the tumor free from the dura, it is
removed along its edges with water dissection
and cottonoids. With more room and better vis-
ualization of the vascular structures the dural
attachment can then be removed. Dural repair
is again performed either with the vascularized
periostal flap or artificial dural substitute.
It is often difficult to identify the exact du-
ral origin based on the preoperative images.
It is not until the actual surgery that we see,
whether the dural origin is at the convexity or
from the falx. In falx meningiomas the resec-
tion of the cortical dura is not always possible,
sometimes even unnecessary, and there may be
no need for duraplasty. In general, we tend to
prepare for the more complicated option while
planning the surgery and then modify our
strategy based on the actual situation.
6.4.3. General strategy with falx and
tentorium meningiomas
Falx and tentorium meningiomas differ from
typical convexity meningiomas mainly due to
their possible invasion into a venous sinus, typ-
ically the superior sagittal sinus or transverse
sinus in the same way as parasagittal meningi-
omas. Preoperative MRA, DSA or CTA with ve-
nous phase are helpful in determining whether
the sinus is still patent or occluded. In case of
a patent sinus, we generally leave the tumor
infiltrating the sinus intact and later treat this
region with stereotactic irradiation. Chasing the
tumor all the way into the sinus often results
in damage to the sinus and sinus thrombosis
with possible catastrophic venous infarctions.
Repairing a damaged sinus intraoperatively is
very demanding as it bleeds profusely. Even if
the repair is initially successful, sinus throm-
bosis can still occur several days later. Along
the anterior one third of the superior sagittal
sinus the risk of venous infarctions is smaller,
but we seldom resect the sagittal sinus even at
this location. If the sinus is truly occluded, then
partial resection of the sinus together with the
falx is possible.
In the similar fashion as for parasagittal menin-
giomas, the craniotomy should be planned ac-
cording to the exact tumor location and tumor
size, so that the whole tumor can be visualized
well. The craniotomy is planned to extend on
both sides of the sinus, more on the side where
the majority of the tumor is. It is much easier
to repair an accidentally severed sinus if one
has good access to both sides. Also, with this
kind of craniotomy one is able to push the ve-
nous sinus together with the falx or tentorium
slightly to the opposite side to gain a little ex-
tra room for dissection. In planning the dural
opening one has to take into consideration the
presence of bridging veins running from the
cortical surface to the dural sinus. These veins
should be left intact during the operation, so
the opening needs to be usually a little longer
alongside the sinus than what the tumor size
itself would require to facilitate tumor dissec-
tion in between the bridging veins. The dura is
opened as U- or V-shaped flap with the base
towards the venous sinus. In bilateral falx
meningiomas or tentorial meninigiomas with
major extension to both the supra- and infra-
tentorial region, the dural opening has to be
planned on both sides of the venous sinus. If
the tumor is only on one side, unilateral dural
opening is sufficient. The same applies for tu-
mors with little extension to the opposite side
but with an occluded sinus.
With the dura opened, the first step is to gain
more room by releasing CSF. In falx meningi-
omas this means entering into the interhemi-
spheric fissure, in tentorium meningiomas into
the superior cerebellar cistern and the quad-
rigeminal cistern. Once the brain is relaxed, the
whole attachment of the tumor to either the
falx or the tentorium must be visualized. Tumor
removal starts with coagulation of the whole
dural attachment. This removes majority of the
tumor's blood supply facilitating cleaner sur-
gery. With the dural attachment disconnected,
Meningiomas | 6

222
part of the tumor may be debulked with suction
if necessary to provide more room. Otherwise,
the dissection plane along the borderline of the
tumor is identified and expanded with water
dissection and cottonoids. All the arachnoid
attachments, the arterial feeders and veins are
coagulated and cut. The whole tumor is encir-
cled until it is freed and can be removed in ei-
ther a single piece or several pieces depending
on the size of the tumor and the room provided
in between the bridging veins. All the passing-
through arteries and veins should be left intact.
The same applies for bridging veins.
Depending on patient's age, other diseases and
the patency or occlusion of the venous sinus,
the falx or tentorium is then either resected
along the area of the original dural attachment
or the dural attachment site is just further co-
agulated. If the sinus is occluded, we usually
choose to resect the dura with the occluded
sinus. Before cutting the occluded sinus, we
ligate it with several sutures proximal and dis-
tal to the planned resection segment. In situa-
tions with a patent sinus, resection of the dural
attachment has to be planned so that it starts
just below the lower margin of the sinus. In
older patients, or if the dural tail is only very
small, instead of resecting the dura, we may
only coagulate it thoroughly over a wider area.
This is done with blunt bipolar forceps and a
higher than usual setting of coagulation power
for intracranial work (50 on our Malis device).
We resect the tentorium less frequently than
the falx, since the tentorium is often more
difficult to access and there are more venous
channels running inside it.
In bilateral tumors the strategy of tumor re-
moval may be a little different. There are actu-
ally two different options. The first option is to
handle tumor extensions on both sides in the
similar way as described above, followed by
resection of the falx or tentorium. The other
option is, to start directly with coagulation and
cutting of the falx anterior and posterior to the
tumor, as this devascularizes both sides at the
same time. The tumor is then detached on both
sides along its border and removed as a sin-
gle piece. This strategy is really feasible only in
situations with an occluded venous sinus.
The dural flap can be often sutured directly
along the line it was opened, unless, the ve-
nous sinus has been partially removed leaving a
large dural defect. In such a case, duraplasty is
performed either with a periosteal flap or some
artifical dural substitute. As with convexity
meningiomas, the original bone flap is placed
back if intact, but in case of tumor invasion,
immediate cranioplasty is performed.
6.4.4. General strategy with skull base
meningiomas
The skull base meningiomas are the most com-
plex group of all the meningiomas. They origi-
nate from different locations at the base of
the skull and due to their central location they
are frequently involved with large intracranial
arteries as well as the cranial nerves and im-
portant basal structures of the brain. It is cer-
tainly very different to plan surgery for a small
olfactory groove meningioma than for a large
petroclival meningioma. Each of the most com-
mon locations has its specific anatomic and
functional considerations. It is not possible to
address all these issues in this relatively limited
text, but we try to present some of the general
considerations for surgery of these lesions.
In large skull base meningiomas, some neuro-
surgeons aim to remove the tumor to the last
tiny portion through extensive skull base ap-
proaches, even if the tumor is extensively in-
volved with vessels and cranial nerves. Others
do not want to touch these lesions at all. Our
policy has lately shifted in the direction of small
approaches and sometimes only partial remov-
al of the tumor. We target only that portion
of the tumor, which can be accessed through
small and targeted openings, without exten-
sive drilling of the skull base and without tak-
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223
ing extreme risks of postoperative cranial nerve
deficits. If there is some tumor left behind, this
is either followed, or treated with stereotac-
tic radiosurgery. We are well aware, that with
some of the huge skull base approaches it is
possible to obtain slightly better tumor remov-
al rate, but the downsides of these approaches
are frequent postoperative complications and
neurological deficits. Many times, even in the
best and most experienced hands, there is still
some tumor left behind even after this kind of
extensive removal and the patient is left with
much worse deficits than what would be the
case after a less ambitious approach. Whenever
it is possible to remove the whole tumor with
reasonable risk, we go for this option. But in
large and invading skull base meningiomas, e.g.
meningiomas invading into the cavernous si-
nus, we have learned to be more conservative.
The approaches used with skull base menin-
giomas depend entirely on the exact location
of the tumor. The approach is always selected
so that it provides the best possible view to-
wards the dural origin of the tumor as well as
to the major vascular structures and cranial
nerves. Since most of the tumors are relatively
far away from the actual craniotomy site, the
keyhole principle can be applied. The only truly
extensive approach we use is the presigmoid
approach for petroclival meningiomas. For
other locations we generally find our normal
small approaches sufficient (see Chapter 5).
In re-do cases, we try to select a different ap-
proach than what was used in previous surgery
to evade the tedious process of going through
arachnoid scarring.
Intradurally, the first task is always to relax the
brain by removal of CSF from the appropriate
cisterns. The actual tumor is approached only
after a slack brain has been achieved. With
more room for dissection, the tumor location
is inspected and all the surrounding arteries,
veins and cranial nerves are identified. The final
strategy for tumor removal is planned based on
visual inspection of the surroundings as well as
on how the tumor is involved, possibly encir-
cling or invading all the important neurovas-
cular structures. Any vessels or nerves covering
the tumor are carefully dissected free and mo-
bilized if possible.
With the dural origin of the meningioma visible,
we start devascularizing the tumor by traveling
along the dural attachment, coagulating and
cutting it. The aim is to cut off the main blood
supply, which comes through the base of the
tumor. Sometimes the tumor may be so big,
that it prevents identification of the structures
covered by it. To obtain some room for better
visualization of the surrounding structures, the
tumor is usually partially debulked, before the
removal continues. For debulking, the tumor is
entered with constant blunt bipolar coagula-
tion (higher setting than normally, Malis 50-
70), and the macerated and coagulated tumor
tissue is removed with suction. An ultrasonic
aspirator is seldom used because the combined
repetitive movement of suction and bipolar for-
ceps achieves the same result with less bleed-
ing. Once there is sufficient room, the dissec-
tion continues along the tumor surface. Water
dissection is used to gently expand the plane
between the tumor and the brain tissue. Skull
base meningiomas have frequently also other
feeders than just the dural attachment. These
can be often seen already on the preoperative
images as originating from one of the major
intracranial arteries or one of their branches.
Careful identification and disconnection of all
these small feeders should be performed un-
der high magnification. Each feeder or vein
should be coagulated and cut. If any of these
small vessels are torn accidentally, they usu-
ally retract backward into the brain tissue and
become very difficult to identify and to coagu-
late. The devascularized tumor is then removed
either in a single piece or in several pieces de-
pending on the anatomical situation.
In skull base meningiomas we do not resect
the dural attachment routinely. Rather, with
the tumor removed, we carefully coagulate the
Meningiomas | 6

224
whole dural origin with bipolar forceps (Ma-
lis 50-70). In patients with a long life expect-
ancy and suitable anatomical conditions, the
dura near the origin of the tumor is stripped
off with either a monopolar or knife, and the
hyperostotic bone is drilled away with a dia-
mond drill. The diamond drill can also be used
to stop some of the small oozing coming from
the bone. Fat and fascia graft together with
some artificial dural substitutes and fibrin glue
are used to cover dural and bony defects of the
skull base to prevent CSF leakage. Seldom, a
bone graft taken from the bone flap is added to
seal a bony defect at the skull base. Finally, the
craniotomy as well as the wound are closed in
standard fashion.
6.4.5. Tumor consistency
In essence the consistency of meningioma tis-
sue varies from very soft and almost transpar-
ent tissue, which can be easily sucked away, to
very hard calcified tissue, which can be removed
only in small pieces. So far, it has not been pos-
sible to accurately determine the tumor con-
sistency from preoperative MRI images, so one
never really knows until the tumor has been
exposed. A hard tumor is always more difficult
to remove than a soft tumor. A hard meningi-
oma cannot be properly debulked. Even slight
manipulation leads easily to compression and
possible damage of the surrounding structures,
and a hard tumor is more difficult to coagu-
late. Postoperative complications in the form
of cranial nerve deficits are more frequent in
patients with a hard tumor. In convexity men-
ingiomas the tumor consistency does not play
that much of a role, but especially in skull base
tumors it very much determines how much of
the tumor can be removed and whether ex-
tensive removal should be attempted or not. A
hard tumor, which is involved with surrounding
structures and possibly invading into the e.g.
cavernous sinus is better partially left behind
than risking significant postoperative deficits
due to extensive manipulation of neurovascu-
lar structures. A soft tumor, where suction can
be used to remove tumor remnants from small
gaps in between the important structures, can
be removed more completely. Furthermore, the
tumor consistency does not seem to be indica-
tive of its grade.
6.4.6. Approaches
For convexity meningiomas the patient posi-
tion and approach is selected so as to provide
the best possible visualization and access to
the whole tumor. The neuronavigator is often
of help in planning the exact location of the
craniotomy and the skin incision. We use su-
pine, park bench, semi-sitting or sometimes
even prone position for convexity meningi-
omas. The important thing to remember is to
keep the head well above the cardiac level to
keep the bleeding at a minimum.
For parasagittal and falx meningiomas the most
common positions are supine, semi-sitting and
prone combined with the interhemispheric ap-
proach. The exact position depends on the lo-
cation of the tumor in anterior-posterior direc-
tion. The aim is to have a relaxed posture for
the surgeon but at the same time both anterior
and posterior border of the tumor should be
visualized.
Tentorium meningiomas are operated on either
in lateral park bench position or in sitting posi-
tion. The lateral park bench position is used in
tentorium meningiomas, which have the major
part of the tumor mass supratentorially. The sit-
ting position with supracerebellar-infratentori-
al approach is used for tentorium meningiomas
that are mainly infratentorial. Prone position is
problematic, because it requires the chin to be
flexed considerably downwards and the head
to be placed well below the cardiac level to
obtain a good visual trajectory infratentorially.
This, on the other hand, increases the venous
bleeding and makes the surgery more difficult.
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225
All of the anterior fossa, parasellar and sphenoid
wing meningiomas are operated through the
LSO approach. Medial sphenoid meningiomas
with extension into the middle fossa need an
LSO approach with temporal extension or pte-
rional approach. The subtemporal approach is
used for meningiomas of the lateral wall of the
cavernous sinus and those of the anterior and
middle parts of the middle fossa. Petroclival
meningiomas usually require a presigmoid ap-
proach with partial resection of the petrous
bone. Meningiomas of the cerebellopontine
angle are approached via a retrosigmoid ap-
proach. Those at the level of foramen magnum
are approached either through the "enough"
lateral approach to the foramen magnum or,
infrequently, using a sitting position and the
low midline approach.
6.4.7. Devascularization
Devascularization of the tumor is the corner-
stone of every meningioma surgery. As already
described earlier, most of the tumor's blood
supply comes from the dural base. Thus, this
should be attacked first. For skull base, falx and
tentorium meningiomas the best technique is
to coagulate with bipolar forceps along the du-
ral surface and detach the whole base in step-
by-step fashion. In convexity and parasagittal
meningiomas it is possible to detach the tumor
from the dura as well, but this process is of-
ten more time consuming and does not provide
any true benefits if compared with immediate
excision of the dura around the whole tumor.
We prefer to do this step under the microscope
to prevent unnecessary damage to any cortical
or passing-through vessels. In general, most of
the arteries and veins are found beneath the
tumor on surface of the cortex, but especially
close to the midline there may be vessels cov-
ering the tumor as well.
With the dural attachment cut, the remain-
ing blood supply of the tumor will come from
smaller or larger perforators surrounding the
tumor. In convexity meningiomas this is less
frequent than in the other meningioma types.
Extra feeders are also more often found in
large tumors than in small ones. The trick here
is to use high magnification and, while dis-
secting the tumor from its surroundings along
the tumor surface, to identify all the feeders
and veins, and to coagulate and cut them pre-
emptively. Coagulating the vessels is often not
enough, since they may overstretch while the
tumor is manipulated, and be accidentally torn.
These torn, small vessels tend to retract into
the brain and continue to bleed from there. In a
large resection cavity it may become extremely
difficult to reach some of the retracted vessels
later on as they may be hidden behind a corner.
We prefer not to enter the tumor itself, unless
it is necessary for debulking purposes. Even
then it should be done cautiously with bipolar
and suction rather than ultrasonic aspirator to
keep the bleeding at minimum. Preoperative
embolization of the tumor may be beneficial in
case the tumor is large and highly vascularized.
Even then the attempt should be made to oc-
clude the small perforators and feeders instead
of the big ones, which are usually easy to han-
dle during surgery, a situation similar to AVM
surgery.
6.4.8. Tumor removal
The crucial part of dissecting a meningioma
is to find the proper dissection plane between
the tumor and the brain. Sometimes there is a
clearly defined arachnoid plane that is easy to
follow, but at times the tumor can be densely
attached to the cortex. We use water dissec-
tion extensively when detaching meningiomas
from their surrounding. The small arteries and
veins are left intact by the water dissection, so
they can be then either coagulated and cut or
saved in case of passing-through vessels.
We start the dissection at a location where the
borderline between the tumor and the cortex
Meningiomas | 6

226
can be clearly defined. The arachnoid plane is
first expanded with water dissection. Saline is
injected with a blunt needle along the dissec-
tion plane that expands and pushes the tumor
away from the cortex. Then under high mag-
nification the tumor is pushed away from the
cortex and arachnoid attachments and feeders
are coagulated and cut. Small cottonoids are
inserted into the already dissected location and
the dissection continues in the same stepwise
fashion along the whole surface of the tumor.
During dissection the tumor should be at all
times pulled away from the brain tissue and
one should compress the brain as little as pos-
sible. One should remember that while pulling
the tumor away from the brain on one side, it
may be pushed against the brain on the op-
posite end. This is important in situations when
the brain is edematous and there is lack of
space. CSF release and partial debulking of the
tumor should help under these circumstances.
T&T:
When removing a meningioma, always work
away from the normal brain tissue.
Even if we decide to remove the tumor in
pieces, we first devascularize and detach a cer-
tain portion of the tumor along its border and
only after that we cut and remove this piece
with microscissors. We no longer use loop dia-
thermia except in very special cases of a very
hard tumor. In our experience, the current from
diathermia spreads over a larger area causing
easily damage to the surrounding neuronal and
vascular structures. In addition, the resection
bed may start to bleed after each slice is re-
moved and one has to spend a lot of time on
hemostasis before proceeding any further.
Sharp dissection and high magnification are
used at sites where the tumor is attached to
either nerves or important vascular structures.
The aim is to preserve all these structures in-
tact and remove only the direct attachments
to the tumor. Saving a passing-through artery
may easily turn the otherwise and straightfor-
ward removal of a small convexity meningioma
into a tedious and time consuming procedure.
But we feel this is time well spent, and with
time and experience it also becomes easier.
Once the whole tumor has been removed, the
whole resection cavity is inspected for any pos-
sible tumor remnants and all the small bleed-
ing points are coagulated once again. The walls
of the cavity are covered with Surgicel, some-
times also with fibrin glue.
6.4.9. Dural repair
In skull base and falx meningiomas we always
weigh the benefits and potential harm caused
by removing the dural origin. In case there is a
larger defect in the basal dura, we try to seal
it either with fascia or artificial dural graft. In
addition, fat graft is used in situations with
potential CSF leak. The more extensive the re-
moval of the bone and the larger the dural re-
section, the greater also is the subsequent risk
for postoperative CSF leak.
In patients with convexity meningiomas we
often use a vascularized pedicled periosteal
flap, which was prepared already during open-
ing. This pedicled flap is sutured to the edges
of the dural defect with a running suture along
the entire defect. The other possibility is to use
an artificial dural graft, which saves the time
of detaching the periosteal flap. The problem
with the artificial grafts is that they are usually
more difficult to seal watertight. Irrespective
of the dural closure method, we do experience
subcutaneus CSF effusions in some patients.
Most of them are easily treated with compress
dressings, but some may require a spinal drain
for a few days.
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227
6.5. GLIOMAS
Gliomas are frequent targets for intracranial
microneurosurgery. The aim of the operation is
two fold: (1) to remove as much of the tumor
as possible without causing new neurological
deficits, and (2) to obtain accurate histological
diagnosis of the tumor grade. Except for some
grade I tumors, gliomas cannot be cured by
surgery. On the other hand, with good micro-
surgical technique it is possible to remove large
quantities of the tumor mass without causing
damage to the surrounding areas. Since gliomas
usually do not have a clearly defined border,
one of the most challenging tasks is to decide
how far to proceed with the tumor removal and
when to stop. This becomes even more impor-
tant in tumors located close to or in eloquent
areas. New neurological deficits caused by the
surgery decrease the quality of life and there
are even indications that they may shorten the
life expectancy. From the microsurgical point
of view gliomas can be divided into two main
groups: (a) low-grade gliomas (grades I and
II), and (b) high-grade gliomas (grades III and
IV). The surgical strategy and technique dif-
fers slightly between the two groups mainly
due to tumor consistency and vascularization.
The microsurgical strategy has to take also into
account the possible benefits or complications
caused by the surgery.
6.5.1. General strategy with
low-grade gliomas
In low-grade gliomas we aim at more aggres-
sive tumor removal than in high-grade gliomas.
The potential benefit of removing the entire
visible tumor is greater and the recurrence
free survival time can be increased more than
in high-grade tumors. This is especially true
for some grade I gliomas where total removal
may even be curative. The tumor tissue itself
is different from high-grade tumors. Its color
is usually paler than the surroundings, its con-
sistency can be slightly elastic, and it does not
bleed much. It does not contain necrotic parts
but there may be cystic components.
The approach and craniotomy is selected so
that the tumor can be visualized well. In corti-
cal tumors the exposure should allow for the
whole tumor with its borderlines to be visual-
ized. In deeper-seated tumors the access route
needs to be such that the whole tumor can be
accessed. The aim is to remove the whole tu-
mor as seen on preoperative images. It is in-
evitable that there will be some tumor cells
left behind at the border due to the infiltra-
tive nature of gliomas. In situations where the
tumor is located in a relatively safe area such
as the anterior portion of the frontal lobe or
anterior part of the temporal lobe, it is often
possible to remove the tumor with a few cen-
timeter margins. Close to eloquent areas this is
not possible and one should stick to the tumor
boundaries.
The intracranial part of the operation starts
with CSF removal and relaxation of the brain.
Especially in large and expansive tumors the
approach should be planned so, that it not
only provides good visualization of the tumor
itself but also gives access to one of the major
cisterns to allow CSF to be released. The ac-
tual tumor removal starts with identification
of the tumor and its borderlines with respect
to the surrounding anatomy. Once the extent
of the tumor is known, it is possible to start
with the actual tumor removal. We plan the re-
section along the borderline, following natural
anatomical planes if possible, such as gyri and
sulci. All the passing-through vessels should
be saved. The cortex is devascularized at the
entry point, incised and entered with bipolar
forceps and suction. We follow the borderline
while constantly coagulating and suctioning
the softened tumor tissue. The ultrasonic as-
pirator may be helpful in low-grade gliomas
Gliomas | 6

228
since the tumor tissue is not very vascularized
and does not bleed much. But while using the
ultrasonic aspirator, one has to be aware of the
course of all the major arteries and veins not to
accidentally severe them. Initial tumor decom-
pression may be sometimes necessary to obtain
better access to the borderline region. The tu-
mor resection along the predefined borderline
continues until the major tumor mass can be
removed either in one or several pieces. With
the major portion removed, the resection cav-
ity is closely inspected and the resection con-
tinues with removal of the portions that have
been left behind. The aim is to reach relatively
normal looking brain tissue at the borderline.
All the small bleedings from the resection cav-
ity must be stopped and finally the resection
cavity is lined with Surgicel. The dura and the
craniotomy are closed in standard fashion.
6.5.2. General strategy with
high-grade gliomas
In high-grade gliomas, surgical treatment is
only part of the whole treatment process. Our
presenttreatmentstrategyistoremoveasmuch
of the contrast-enhancing tumor as possible,
followed by radiotherapy or more frequently
by chemo-radiotherapy. Each case is discussed
in our neuro-oncology group that consists of
neurosurgeons, neuroradiologists, neurologists,
neuropathologists and neuro-oncologists.
The surgery itself aims at removal of the tumor
mass, but again with minimizing the risk of
neurological complications. New postoperative
deficits may actually shorten the life expect-
ancy of these patients. However, this does not
mean that we would settle only for moderate
internal decompression as may be the policy in
many departments. If we decide to go for open
microsurgical operation, than we try to use all
our technical skills to remove as much of the
enhancing tumor as possible while preserving
all the surrounding structures. Especially in
older patients with deep-located tumors, we
may choose only stereotactic biopsy followed
by radiotherapy.
The approach is selected so that the tumor can
be reached optimally. High-grade gliomas are
usually more vascularized than low-grade glio-
mas, which has to be considered while plan-
ning the tumor removal. Slack brain is obtained
by release of CSF from various cisterns. Addi-
tional room may be achieved by internal tu-
mor decompression, or by releasing fluid from
the cysts inside the tumor if present. Entering
into the actual tumor results often in bleeding
from its numerous pathological feeders. While
the outer border of the tumor is highly vascu-
larized, the innermost portion may be almost
avascular, necrotic and sometimes cystic. The
vascularized tumor tissue is often darker or
redder than the surrounding brain, while the
necrotic portions are yellowish and may con-
tain thrombosed veins. The high vasculariza-
tion and tendency to bleed is the reason why in
malignant gliomas the use of ultrasonic aspira-
tor is kept at a minimum. Instead, we prefer to
remove the tumor with constant coagulation
of blunt bipolar forceps in the right hand and
small repetitive movement of the suction in the
left. This technique provides better hemostasis
throughout the procedure.
In superficial tumors the removal should be per-
formed in a very similar way as with AVMs. The
tumor should be followed along the borderline,
coagulating and making hemostasis all the time.
The center of the tumor is not entered unless
necessary for decompression purposes. This
keeps the bleeding at a minimum. In tumors
located either close to eloquent or subcortical
areas, we alter this approach strategy. In these
cases, we enter into the tumor directly and per-
form most of the removal from inside out. In this
way we try to manipulate as little of the sur-
rounding functional tissue as possible. Constant
use of bipolar coagulation is a must to keep the
bleeding at minimum. While inside the actual
tumor tissue, the risk of causing new neurologi-
cal deficits is small. The problems arise close to
6 | Gliomas

229
the borderline of the tumor. Like with low-grade
tumors, there will be always tumor tissue left
behind due to the infiltrative nature of the glio-
mas. But the contrast enhancing tissue is usu-
ally removed, once the resection surface stops to
bleed and the tissue starts to look similar to nor-
mal white matter. The use of 5-ALA with a suit-
able microscope camera system helps in iden-
tifying the borderline of the enhancing tumor.
All passing-through arteries should be saved in
the same way as with low-grade gliomas. Once
the tumor has been removed to the best of our
knowledge, careful hemostasis is performed
along all the walls of the resection cavity and
the resection bed is lined with Surgicel.
The closure is performed in a normal fashion in
layers. In redo-surgeries of patients with previ-
ous radiation therapy the skin tends to be thin
and atrophic. In these cases, risk of postopera-
tive subcutaneous CSF collection as well as CSF
leakage through the wound is much higher.
Both the subcutaneous and the skin layer have
to be closed even more carefully than usual
and we keep the skin sutures in place for long-
er, sometimes even several weeks, before the
wound has properly healed.
6.5.3. Approaches
In glioma surgery, the tumor location de-
termines the exact approach to be used. We
use all the different positions (supine, lateral
park bench, prone, semi-sitting, and sitting)
described earlier in Chapter 5. Our aim is to
get to the tumor along the natural anatomi-
cal planes while damaging as little of the nor-
mal tissue as possible. The craniotomy should
provide nice and easy access to not only the
tumor, but it should also allow CSF release in
situations with lack of space. The head should
be well above the heart level to allow for bet-
ter venous drainage and less swelling. In corti-
cal tumors the craniotomy and dural opening
is usually larger so that the bordelines of the
whole tumor can be accessed. In deeper-seated
lesions the access route can be small, based on
the keyhole principle.
While planning the skin incision one should re-
member that especially in malignant gliomas,
the patient is likely to receive postoperative
radiotherapy. Straight or only slightly curved
incisions tend to heal better as they have more
extensive blood supply, than flaps with only a
narrow pedicle.
6.5.4. Intracranial orientation and
delineation of the tumor
Due to the infiltrative growth of the gliomas,
intracranial orientation and delineation of the
tumor is one of the most difficult tasks in any
glioma surgery. On the cortex, the tumor tis-
sue itself can be often recognized by a darker
color, but its borderline is not sharp, so one has
to estimate where the tumor ends and normal
tissue begins.
Whenever possible, we try to orientate accord-
ing to anatomical structures. Natural planes or
vascular structures can be utilized as orienta-
tion marks. One should also plan the operation
in steps so that removal of each part of the
tumor should end once a certain anatomical
structure has been reached. Often there are no
clearly defined anatomical structures in the vi-
cinity. Then the only option is to rely on one's
3D imagination, careful inspection of the tis-
sue, using a ruler, and pure intuition. Measuring
the tumor dimensions on preoperative images
and comparing them with on-site ruler meas-
urements provides usually good estimate of the
extent of the tumor resection. Before the tumor
removal starts, one needs to have a rough plan
about the dimensions of the tumor in differ-
ent directions as well as the location of all the
potentially endangered structures. It is almost
impossible to orientate oneself if the surgery is
entered midway through. The initial inspection
and orientation phase is better performed with
less magnification as it helps in understand-
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230
ing the different dimensions. Once the actual
tumor removal starts, we go to a higher mag-
nification. If one gets lost midway through the
surgery, reducing the zoom and careful meas-
urements with the ruler usually help.
In tumors close to eloquent areas we like to use
the neuronavigator. It is helpful while planning
the approach and identification of the border-
lines of the tumor immediately after the dura
has been opened. Once CSF has been released
and part of the tumor debulked, the informa-
tion provided by the neuronavigator becomes
less accurate.
Constant coagulation of the tumor tissue with
blunt bipolar forceps and suctioning of the
macerated tissue away is the most important
technique for removing gliomas. Unlike with
the ultrasonic aspirator, the use of bipolar for-
ceps not only dissects the tumor tissue but also
coagulates. Whenever there is a bleeding, it is
better to spend time to coagulate it completely
before proceeding further. Once the resection
surface increases, all the small oozing trans-
forms into a pool of blood which is much more
difficult to handle. We like to flush the opera-
tive area frequently with saline, as this helps in
identifying all the small bleeding points.
We often use cottonoids to mark different
dissection borders of the tumor. This helps in
orientation towards the borderline when ap-
proaching the same borderline from a different
direction. At the same time the cottonoid tam-
ponades the resection surface and lessens ooz-
ing from the resection bed. In larger resection
cavities the cottonoids can be used to prevent
the cavity from collapsing facilitating easier
removal of the remaining tumor.
During glioma surgery, it is essential to take
many representative samples of the tumor. We
take some samples already from the borderline
of the tumor and then continue throughout the
procedure, whenever there is some change of
consistency in the tumor tissue. Frozen sec-
tions are analyzed immediately, but it takes
usually about a week before the final grading
is obtained.
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231
6.6. COLLOID CYSTS OF THE THIRD VENTRICLE
Colloid cysts are small-sized, well-circum-
scribed and relatively avascular lesions, prin-
cipally ideal for surgical removal. However,
their deep location in the midline poses its
challenges. Nowadays, with good illumination,
magnification, and improved imaging and sur-
gical techniques, third ventricle colloid cysts
can be removed safely. There are several pos-
sible approaches and techniques which can be
used to operate on colloid cysts including: (a)
interhemispheric route and lateral transcallosal
approach; (b) interhemispheric route and mid-
line transcallosal route between the fornices;
(c) transcortical route directly into the lateral
ventricle; (d) sterotactic approach; and recently
(e) endoscopic approach. Of the microsurgical
approaches we prefer the lateral transcallosal
approach via the interhemispheric route. In this
approach the risk for damaging either fornix is
extremely small as the lateral ventricle is en-
tered way lateral from the midline. Compared
to the transcortical approach, the trancallosal
approach involves only a small part of the com-
missural system, whereas the transcortical ap-
proach injures several layers of connective sys-
tems and other essential components of white
matter. The endoscopic approach provides best
illumination and visualization of the lesion and
its surroundings. Unfortunately, the instru-
ments are still very rudimentary compared to
microsurgical instruments and do not provide
as good control over the situation as one would
wish for.
6.6.1. General strategy with colloid
cyst surgery
The most important cause of symptoms from
the third ventricle colloid cyst is hydrocepha-
lus. The aim of the removal of the colloid cyst is
to free both foramina of Monro and to normal-
ize the CSF flow. Simple aspiration of the fluid
from inside the colloid cyst seems to result in
more frequent recurrences than if the cyst is
removed completely including its outer layer.
We prefer the interhemispheric route with
transcallosal opening lateral to the midline to
arrive directly at the frontal horn of the lat-
eral ventricle at the level of foramen of Monro.
A right-sided approach is usually more con-
venient for a right-handed neurosurgeon. The
potential complications of this approach arise
mainly from damage to the bridging veins,
damage to the fornix at the level of foramen of
Monro (infrequent), and intraventricular bleed-
ing from the small feeders of the colloid cyst.
In addition, there is the possibility of entering
the lateral ventricle either too anterior or too
posterior, which may result in orientation prob-
lems and difficulties in accessing the foramen
of Monro and the colloid cyst. All the steps of
the operation should be planned to minimize
these potential problems.
6.6.2. Positioning and craniotomy
The patient is placed in a semi-sitting position
and fitted with G-suit trousers. The head is
slightly flexed, but there is no rotation or later-
al tilt. We use the Sugita head frame for semi-
sitting position. With the correct head position
the approach trajectory is almost vertical. Tilt-
ing the head to either side increases the chance
that the bone flap is placed too laterally from
the midline. This would make the entrance
into the interhemispheric fissure and naviga-
tion there more difficult. A slightly curved skin
incision is planned with its base frontally just
behind the coronal suture. The incision extends
on both sides of the midline, little more on the
side of the planned approach. A one-layer skin
flap is reflected with spring hooks frontally and
one spring hook is used to spread the wound
also in the posterior direction. Without this
posterior spring hook the whole bony expo-
Colloid cysts of the third ventricle | 6

232
sure can migrate too anterior due to the heavy
spring hook retraction of the skin. This would
then lead to a too anterior intracranial angle of
approach. The coronal suture should be about
midway through the exposed area. The crani-
otomy and opening of the dura are performed
as described in section 5.2.3.
6.6.3. Interhemispheric approach
and callosal incision
With the dura open and the cortex exposed,
before any brain retraction, it is mandatory to
be oriented to the landmarks that lead toward
the foramen of Monro. The best guide is an im-
aginary line drawn from the coronal suture at
the midline to the external auditory meatus,
the line used in ventriculography to get the
catheter inside the third ventricle. It is also im-
portant to check the angle of the microscope is
in line with the planned approach trajectory.
Upon entering the interhemispheric fissure,
bridging veins may obstruct the view, prevent-
ing even the slightest retraction of the frontal
lobe. The veins are likely to restrict the work-
ing area, and one may have to work between
them. It may help to dissect some of them for
one or two centimeters from the brain surface.
Cutting a few small branches may allow safe
displacement of the major trunk. One may have
to sacrifice a smaller vein, at the risk of venous
infarction though. Extensive and long-lasting
use of retractors, obstructing the venous flow,
may have the same result as severing a bridg-
ing vein.
We use water dissection to expose and to ex-
pand the interhemispheric fissure for further
dissection. Arachnoid membranes and strands
are cut sharply by microscissors, which can
be also used as a dissector when closed. Use
of retractors is kept at a minimum, and they
are not routinely used at the beginning of the
approach. Instead, bipolar forceps in the right
hand and suction in the left, with cottonoids of
different sizes as expanders, are used as micro-
retractors. When the interhemispheric fissure is
widely opened and the frontal lobe mobilized,
the retractor may be used to retain some space
but otherwise should be avoided. Rolled cot-
tons, placed inside the interhemispheric fissure
at the anterior and the posterior margin of the
approach, gently expand the interhemispheric
working space and reduce the need for me-
chanical retractors.
Insidetheinterhemisphericfissure,aftercutting
the arachnoid adhesions, dissection is directed
along the falx toward the corpus callosum. At
the inferior border of the falx, dissection plane
is identified between the cingulate gyri at-
tached to each other. The dissection must be
continued deeper toward the corpus callosum,
identified by its white color and transverse fib-
ers. Mistaking the attached cingulate gyri as
the corpus callosum or other paired arteries as
the pericallosal arteries lead to serious prob-
lems of navigation. After reaching the corpus
callosum, the right hemisphere is usually well
mobilized and can be gently retracted approxi-
mately 15 mm.
Once inside the callosal cistern, both perical-
losal arteries are visualized, realizing that they
can be on either side of the midline. The right
pericallosal artery is dissected and displaced
laterally avoiding the damage of the perforat-
ing arteries directed laterally to the right hemi-
sphere. Sometimes there can be also crossover
branches providing vascular supply to a small
area of the medial wall of the contralateral
hemisphere. The callosal incision, confined to
the anterior third of the body of the corpus cal-
losum, is performed medial to the right sided
pericallosal artery but as lateral as possible to
preserve the fornix. If hydrocephalus is present,
the corpus callosum is thin; otherwise, it can
be up to 10 mm thick. With sharp bipolar for-
ceps, an oval callosotomy of less than 10 mm
is performed. Its size tends to increase slightly
during the later stages of the surgery.
6 | Colloid cysts of the third ventricle

233
As the callosal transit is completed, formerly,
a retractor was placed to prevent collapse of
the lateral ventricle. Nowadays, we usually use
only bipolar forceps and suction as retractors.
Additionally, a thin cottonoid can be inserted
into the callosal opening to keep it open, and
to protect the pericallosal artery. Inside the lat-
eral ventricle, the foramen of Monro is found
by following the choroid plexus and the thala-
mostriate vein anteriorly and slightly medially
towards their convergence point. The antero-
medially located septal vein joins the thalam-
ostriate vein at the foramen of Monroe to form
the internal cerebral vein, which runs in the
roof of the third ventricle. The correct orien-
tation is given by the lateral ventricular veins,
which become larger as they approach the fo-
ramen of Monro. Opening of a small window in
the septum pellucidum is effective to release
CSF from the contralateral lateral ventricle. In
patients with hydrocephalus, the septum pellu-
cidum is often thin and may have been already
perforated by itself.
6.6.4. Colloid cyst removal
First, the part of choroid plexus that is often
overlying and eventually even hiding the cyst, is
coagulated to expose the cyst. The cyst is then
opened with a fine hook or microscissors. The
opening is widened with straight microscissors.
The contents of the cyst are removed with suc-
tion and bipolar forceps. If the cyst consists of
more solid material, a small ring forceps can be
used for its removal. The remaining contents
of the cyst as well as its wall are resected with
microscissors. The colloid cyst is usually at-
tached to the roof of the third ventricle and the
tela choroidea. This attachment, usually one
artery and two veins, has to be coagulated and
cut to avoid bleeding from these small vessels.
After removal of the cyst, irrigation should be
clear, confirming adequate hemostasis. Brain
collapse and postoperative subdural hematoma
is a potential risk in cases with severe preop-
erative hydrocephalus. To prevent this, we first
fill the ventricles with saline and then place a
piece of Surgicel followed by fibrin glue into
the incision of the corpus callosum.
Colloid cysts of the third ventricle | 6

234
6.7. PINEAL REGION LESIONS
Lesions of the pineal region are histopathologi-
cally heterogeneous but often accompanied by
severe progression of clinical signs. Surgical
treatment remains challenging because of the
close vicinity of the deep venous system and
the mesencephalo-diencephalic structures in
this region. Most of the lesions of the pineal
region are tumors, either malignant (germino-
mas, pineoblastomas, anaplastic astrocytomas,
ependymomas, teratomas, and ganglioneu-
roblastomas) or benign (pineocytomas, pineal
cysts, and meningiomas). Vascular lesions such
as AVMs, cavernomas or Galenic vein malfor-
mations comprise only about 10% of the le-
sions. Unfortunately, MRI is not always reliable
in differentiation of malignant pineal region
tumors from the benign ones. Some neurosur-
geons prefer to take a stereotactic biopsy of
a pineal region lesion before deciding to per-
form a microsurgical operation. In our experi-
ence, in most cases, direct surgical treatment
can be offered as the first treatment option
for pineal tumors. We approach these lesions
using the infratentorial supracerebellar route
(see section 5.7.), which is safe and effective,
associated with low morbidity, a possibility for
complete lesion removal, and definitive his-
topathologic diagnosis. Pineal cysts are oper-
ated only if symptomatic, if they increase in
size during MRI follow-up, or if neoplastic na-
ture is suspected.
6.7.1. General strategy with pineal
region surgery
Surgical strategy is planned based on presur-
gical MRI and CT results. MRI and particularly
the study of the deep venous system seem to
be the most valuable modality in planning the
surgical trajectory and assessing structures in
the vicinity of the lesion. In highly vascularized
lesions we also use DSA to identify the arte-
rial feeders that need to be handled first during
the approach to keep the bleeding at a mini-
mum. We prefer the paramedian infratentorial
supracerebellar approach in sitting position
for lesions of the pineal region. The greatest
advantages of this approach are: (1) the deep
venous system is left intact as the approach
trajectory comes from below; (2) the cerebellar
veins in the midline are evaded; and (3) gravity
creates a gap between the tentorium and the
cerebellum without the need for retractors. Our
main strategy is to obtain histological diagnosis
by open microsurgery, followed by total tumor
removal if possible. Some tumors may contain
mixed elements so we prefer to take many tu-
mor samples from various parts of the tumor.
In benign lesions, complete tumor removal is
possible; in malignant lesions, one has to settle
for gross total resection. During tumor removal,
all the venous structures should be left intact
to prevent postoperative venous infarction.
Parinaud's syndrome or diplopia, usually tran-
sient, can be seen postoperatively in about 10%
of the patients, probably due to manipulation
of structures close to the tectum area.
The infratentorial supracerebellar approach
can be performed even in situations with ob-
structive hydrocephalus before the operation.
This can be managed either by releasing CSF
through the posterior wall of the third ventri-
cle, from the cisterna magna, or through an
occipital ventriculostomy. Nowadays, perform-
ing endoscopic third ventriculostomy is a good
option. However, in our experience, obstructive
hydrocephalus can be managed satisfactorily
in the same setting as the tumor surgery, in
most cases by radical excision of the tumor and
opening the posterior third ventricle.
6 | Pineal region lesions

235
6.7.2. Approach and craniotomy
Infratentorial supracerebellar approach in
sitting position has been described in detail
in section 5.7.
6.7.3. Intradural approach
Once the arachnoidal adhesions and possibly
some of the bridging veins between the cere-
bellum and the tentorium have been coagulat-
ed and cut, the cerebellum falls down, allowing
a good surgical view without brain retraction.
Opening of the cisterna magna with removal
of CSF improves the surgical view if needed.
Along the surgical route are the dorsal mes-
encephalic cisterns, and their opening releases
CSF and provides optimal room for further dis-
section. At this point, distinguishing the deeply
located veins from the dark blue-colored cis-
terns is crucial. Exposure of the precentral
cerebellar vein, and coagulation and cutting
of this vein if needed, clears the view; and the
vein of Galen and the anatomy below it can be
identified. This is the most important part of
the operation, but sometimes the thick adhe-
sions associated with chronic irritation of the
arachnoid by the tumor makes this dissection
step difficult. We usually begin the dissection
laterally. After finding the precentral cerebel-
lar vein, we become well oriented towards the
anatomy of the pineal region. During further
dissection, special care is needed not to dam-
age the posterior choroidal arteries.
6.7.4. Lesion removal
The tumor is often covered by a thickened
arachnoid and may not be immediately ap-
parent. After careful opening of the arachnoid
with microscissors and the bipolar forceps, the
tumor is exposed and entered to obtain histo-
logical samples. Debulking of the tumor is per-
formed using suction and mechanical action of
the bipolar forceps, which also coagulates the
vessels inside the tumor. After debulking, the
tumor is dissected free from the surrounding
veins, with the help of water dissection. Dis-
section of the tumor starts from lateral to me-
dial. Eventually, the feeders supplying the tu-
mor from outside are coagulated and cut. The
posterior part of the third ventricle is finally
opened and CSF removed, giving additional
space for better dissection of the rest of the
tumor from its surroundings.
The angle below the posterior commissure
warrants extreme caution because the slight-
est bleeding in this area may have fatal con-
sequences. Therefore, even the smallest vessels
in this angle should be coagulated and cut,
instead of tearing them by manipulating the
tumor. Some of the small vessels may be hid-
den behind the tumor. They may be visualized
by mirror or endoscope. A careful hemostasis is
of the utmost importance, as even the smallest
clot in the third ventricle or the aqueduct may
result in acute hydrocephalus.
In malignant and infiltrative tumors, we per-
form only a subtotal resection. Debulking with
suction and bipolar forceps continues until the
posterior part of the third ventricle is visualized
and entered. The ultrasonic aspirator is seldom
used in the pineal region because the working
space is small and narrow, and extra-long in-
struments are needed, especially in the anterior
part of the tumor. Recently, new ultrasonic as-
pirators have been introduced with longer and
thinner shafts, which could be also used at the
pineal region. If possible, we try to remove the
lesion completely.
Pineal region lesions | 6

236
6.8. TUMORS OF THE FOURTH VENTRICLE
Tumors of the fourth ventricle constitute a
multitude of different lesions, both benign and
malignant. The most common ones are pilo-
cytic astrocytomas, medulloblastomas, epend-
ymomas, hemangioblastomas, and epidermoid
tumors. Although these tumors are different
from a histopathological point of view and they
have different clinical courses, the microsurgi-
cal strategy and planning is rather similar. The
fourth ventricle tumors nearly always present
with posterior fossa mass-syndromes, especial-
ly hydrocephalus. Typically, the fourth ventri-
cle is either partially or completely filled with
the lesion, and the brainstem is compressed
against the clivus. It is not possible to deter-
mine accurately whether the lesion is benign
or malignant based only on the preoperative
MRI images. Therefore the goals of the surgery
are twofold: (a) to obtain accurate histological
diagnosis of the tumor, and (b) to relieve hy-
drocephalus and to remove compression on the
brainstem. These goals can be usually achieved
irrespective of the tumor type.
6.8.1. General strategy with fourth
ventricle tumors
The presenting symptom for a fourth ventricle
tumor is very often hydrocephalus. In patients
with decreased level of consciousness, we in-
sert an extraventricular drain (EVD) as an emer-
gency measure to treat the hydrocephalus. The
actual tumor surgery is then performed either
on the same day or during the next few days.
In situations where the patient might need to
wait for the surgery for several days, instead of
using the EVD, we might opt for a shunt. Unlike
with the EVD, with a shunt the patient can wait
at an ordinary bed ward. Endoscopic third ven-
triculostomy may also be considered, but due
to the tight posterior fossa, there may be very
little room between the clivus and the basilar
artery to carry out the procedure safely. In pa-
tients, whose level of consciousness is good, we
prefer to operate directly on the tumor without
previous CSF diversion procedures. With the
tumor removed, normal CSF flow is usually re-
stored. When planning a shunt, it is good to
remember that a ventriculo-peritoneal shunt
may be a better option in these patients, since
ventriculo-atrial shunt is a relative contrain-
dication for surgery in the sitting position, the
preferred position for fourth ventricle tumors.
In our experience, the fourth ventricle tumors
are best approached using the low posterior
fossa midline approach with the patient in sit-
ting position (see section 5.8.). The advantages
of this approach are: (1) easy orientation to-
wards the midline; (2) the vermis can be left
intact as the fourth ventricle is entered in be-
tween the cerebellar tonsils through the fo-
ramen of Magendie; (3) by rotating the patient
forward, the whole fourth ventricle can be vis-
ualized including the opening of the aqueduct;
and (4) the risk of manipulating or damaging
the anterior wall of the fourth ventricle (i.e.
the brain stem) is smaller since one is working
mainly tangentially to the fourth ventricle, not
perpendicular. Naturally, the advantages have
to be weighted against the risks of the sitting
position (see section 5.8.).
MRI images give important information for the
planning of the resection of a fourth ventricle
tumor. The sagittal view is used to determine
how high the tumor extends and how much
forward tilting will be necessary to reach the
most cranial portion of the lesion. The closer
the tumor is to the aqueduct the more forward
rotation will be necessary. On axial images one
should observe how the compressed fourth
ventricle is related with respect to the tumor. Is
there a CSF plane surrounding the tumor, and
if so, from which directions? The other impor-
tant aspect is the tumor origin or the possible
attachment to the surroundings. Sometimes, it
6 | Tumors of the fourth ventricle

237
might be possible to pinpoint the actual origin,
but in most cases one can only see whether
or not the tumor infiltrates cerebellar tissue
or the brainstem. Especially in situations with
brainstem infiltration, complete removal is un-
realistic, carrying a very high risk of extensive
neurological deficits with it. In such cases our
main aim is to obtain good histological sam-
ples and release the mass effect by debulking
the tumor. In highly vascularized lesions such
as hemangioblastomas, we prefer to do also
preoperative CTA or DSA to visualize the course
of the main feeders.
The anatomic structures at risk during the ap-
proach and the tumor removal are mainly both
PICAs and the posterior portion of the brain-
stem. If the approach is directly in the midline,
as planned, the cranial nerves are not encoun-
tered. However, careless dissection of the tumor
from the brainstem can result in direct damage
to the tracts inside the brainstem or the differ-
ent nuclei. PICAs circle around the brainstem
and medulla oblongata to reach its posterior
aspect, where cerebellar tonsils often cover
them. They turn cranially, pass each other close
to the midline and then deviate back laterally.
The course of both PICAs should be identified
prior to resecting the lateral most portions of
the tumor on either side. The PICAs may also
provide major feeders to the tumor. The actual
PICAs should always be left intact to prevent
postoperative cerebellar infarction.
Our general strategy for actual tumor removal
goes as follows. With the dural opening at the
midline close to the foramen magnum, the
cerebellar tonsils are spread and the region
of the fourth ventricle is entered. The tumor
is partially debulked form inside to provide for
more room. The tumor removal then proceeds
along its posterior border cranially to reach
the tumor free cranial part of the fourth ven-
tricle. Once this has been entered, additional
CSF comes out. The tumor is then dissected
free with special attention to the anterior wall
of the fourth ventricle, which is kept intact.
Whenever possible, we aim for complete tumor
removal. Normal CSF flow is generally restored
by the tumor removal. Shunts are used only in
those patients in whom hydrocephalus remains
also postoperatively.
6.8.2. Positioning and craniotomy
The positioning and craniotomy for this approach
have been described in detail in section 5.8.
6.8.3. Intradural dissection towards
the fourth ventricle
The dura is opened under the microscope. We
use a reversed V-shape flap with the base to-
wards the foramen magnum. Two additional
dural cuts can be made in the supero-lateral
direction if more room is needed, but the singe
reversed V-shaped flap is often enough. Several
sutures are used to lift the dura and to pre-
vent venous congestion of the superficial veins
against the dural edge. The arachnoid is opened
as a separate layer and attached by a hemoclip
to the dural edge to prevent it from flapping in
the operative field. With the arachnoid open,
CSF flows out from the cisterna magna. From
this point onward, we continue under a high
magnification that is maintained throughout
the whole tumor removal.
Using water dissection and small cottonoids
the cerebellar tonsils are gently spread apart.
Arachnoid bands in between the cerebellar
tonsils are stretched and cut with microscis-
sors. The aim is to enter into the fourth ventri-
cle through the foramen of Magendie, which
in most cases is enlarged and filled with the
tumor. Frequently, the tumor can be visualized
Tumors of the fourth ventricle | 6

238
already before even spreading the cerebellar
tonsils. We do not use retractors routinely in
this approach. Instead, to obtain a better view
into the fourth ventricle, the entire table is
rotated forward. Cottonoid(s) can be placed
between the cerebellar tonsils to keep them
apart once they have been mobilized. We try
to identify both PICAs as soon as possible, so
that they can be preserved during the actual
tumor removal. The feeders coming from the
PICA into the tumor are coagulated and cut
under high magnification.
With the caudal portion of the tumor visual-
ized and before the actual tumor removal
starts, we take the first tumor tissue samples
for frozen section histological diagnosis. The
tissue sample is best taken with a ring for-
ceps. In the same way as with intrinsic tumors
in general, we try to take as many samples as
possible from different parts of the tumor, since
the histology may vary throughout the tumor.
After the initial samples, the tumor removal
progresses with partial debulking of the tumor.
The tumor is entered with blunt bipolar forceps
and suction. Under constant and repetitive co-
agulation, the tumor is reduced from within.
Without internal debulking there might be too
little room for dissection of the tumor along
its edges. It is important to remember that
pushing the tumor into the anterior direction
compresses also the brainstem, so this should
be avoided. Some tumors may contain cystic
components, which can be opened to obtain
additional room.
Once the tumor has been partially decom-
pressed, the dissection should continue along
the borderline of the tumor. A natural dissec-
tion plane is identified if present, and this plane
is followed utilizing the techniques of water
dissection, gentle spreading of the dissection
plane with bipolar forceps and sharp dissection
of arachnoid and vascular attachments. The
dissection plane is followed as far as possible.
It is easiest to start the dissection along the
posterior surface of the tumor, since this por-
tion is initially visible. The posterior surface is
exposed in the lateral and especially superior
direction. The aim is to reach the cranial bor-
der of the tumor to gain access towards the
superior part of the fourth ventricle and the
aqueduct. From here additional CSF can be re-
leased. Once the cranial part has been reached,
the dissection turns in lateral direction. In case
of intrinsic tumors, the tumor often originates
from the lateral border on either side. Identifi-
cation of the imaginary borderline of the tumor
may be difficult and one should be very careful
not to accidentally enter the brainstem. If pos-
sible, we prefer to pull the tumor away from the
normal tissue and to resect it along this plane
held under tension. Ring forceps may provide
better grip on the tumor, since they have larger
surface area then bipolar forceps.
In highly vascularized tumors, such as heman-
gioblastomas, the strategy for tumor removal
needs to be a little different. Debulking of the
tumor is not a real option as this would only
result in serious bleeding. Instead, these tu-
mors should be removed in one piece. The aim
is to devascularize them from their major blood
supply as soon as possible. This is the reason for
the preoperative use of CTA or DSA. With the
tumor devascularized, it is then removed either
in one or several pieces.
With the majority of the tumor removed, the
fourth ventricle can be inspected for tumor
remnants. Appropriate table orientation should
provide an unobstructed view all the way into
the aqueduct. Especially ependymomas can
grow also into both foramina of Luschka. They
are difficult to visualize from the midline. The
tonsils may need to be spread wider and the
microscope oriented properly to obtain a suf-
ficient view into the lateral direction. By gen-
tly pulling on the tumor, it may be possible to
dislocate it into view, even those portions of
the tumor that are inside or on the outside of
6 | Tumors of the fourth ventricle

239
the foramina of Luschka. In ependymomas one
should always try to remove the tumor com-
pletely.
Careful hemostasis is carried out along the
whole resection cavity, especially at the re-
gion of the tumor attachment. With minimal
counter pressure, the risk of postoperative
bleeding into the ventricle is high. We try to
avoid coagulation with bipolar forceps, when
the bleeding comes from the anterior surface
of the fourth ventricle, and not to damage the
brainstem. Instead, hemostatic agent such as
TachoSil has proved valuable in this situation.
A small piece is placed along the resection bed
and gently tamponated with cottonoids. In our
experience, it stops the tiny oozing effectively.
It also sticks to the wall of the ventricle and
does not cause obstruction of the CSF flow.
The dura as well as the other layers are closed
in layers in standard fashion. The patient is
taken to the ICU. After two to four hours, a
control CT scan is performed and if everything
looks good, the patient is woken up. In gen-
eral, there should be no deficits of the lower
cranial nerves after this kind of posterior ap-
proach. Despite this, we monitor the swallow-
ing function carefully both before and after the
extubation.
Tumors of the fourth ventricle | 6

240
6.9. SPINAL INTRADURAL TUMORS
The most common spinal intradural lesions are
schwannomas, meningiomas, neurofibromas,
ependymomas, and astrocytomas. In addition,
some vascular lesions such as spinal caver-
nomas, spinal AVMs and spinal dural arterio-
venous fistulas (dAVFs) require a very similar
microneurosurgical approach. The approach
itself as well as the dural incision is almost the
same in all of these entities, whereas the ac-
tual intradural part of the surgery is tailored
according to the pathology. The true challenge
of all the intradural spinal lesions is the rela-
tively small size of both the spinal canal as well
as the structures inside. There is less room for
manipulation and with the narrow approach
route, high magnification and high quality
microsurgical technique are essential in treat-
ing these lesions.
6.9.1. General strategy with intradural
spinal lesions
Nearly all intradural spinal lesions are ap-
proached performing a hemilaminectomy at
the appropriate level. Laminectomy is used only
in those lesions, where the most important aim
of the procedure is decompression of the spi-
nal canal, since the actual pathology cannot be
properly removed, e.g. lipomas, or most glio-
mas. The disadvantage of a hemilaminectomy
might be a smaller lateral exposure of the dura
on the contralateral side, but with partial re-
section of the base of the spinous process and
appropriate tilting of both the microscope and
the table, good visualization of the whole le-
sion can be obtained.
The most difficult task whenever approach-
ing an intradural spinal lesion is to determine
the exact cranio-caudal location of the lesion.
Counting the spinous processes by palpation is
inaccurate and leads easily to wrong level. In-
traoperative fluoroscopy with C-arm is a good
way to determine the appropriate level. Un-
fortunately, this works only in the cervical and
lumbar regions. In the thoracic spine we prefer
marking the appropriate level by methylene
blue injection before the operation. This is car-
ried out by radiologist in the angio suite. After
identification of the targeted spinous process,
a needle is placed at the spinous process and a
small amount of methylene blue is injected to
mark this particular spinous process. The mark-
ing should be preferably done on the same day
as the planned surgery, since the color has the
tendency to spread into the surrounding tissues
with time. Intraoperatively, the blue marking
on the spinous process is then used for orien-
tation.
In extra-axial tumors (meningiomas, schwan-
nomas or neurofibromas) we aim for complete
tumor removal, while leaving the medulla and
all the nerve roots intact. In schwannomas the
tumor typically originates from one of the dor-
sal roots, the sensory root. Although we try to
save this nerve if possible, in most cases the
tumor cannot be dissected free from the nerve
and the tumor is removed together with the
nerve. Fortunately, this seldom leads to any
new deficits. The reason probably is that the
affected nerve root has not functioned prop-
erly for already some time, and its function
has been distributed among the adjacent nerve
roots. In spinal meningiomas we aim for com-
plete tumor removal, but we do not remove the
dura at the site of the tumor origin. The dural
origin is only coagulated with bipolar forceps.
In our experience, this policy does not increase
the recurrence rate.
In intra-axial spinal tumors the histological
nature of the lesion determines our strategy.
In ependymomas one might be able to find a
borderline, which would allow for the tumor to
be separated from the normal tissue. However,
most spinal gliomas grow infiltratively without
6 | Spinal intradural tumors

241
any proper borderline, so that internal decom-
pression with good histological samples and
decompression of the bony spinal canal is all
that can be achieved. Lipomas, although clear-
ly defined on preoperative MRI scans, are ex-
tremely sticky, almost glue-like when it comes
to their removal. They are densely attached to
the medulla and the surrounding nerve roots.
Some of the nerves may be even embedded in-
side the tumor tissue. Most lipomas cannot be
removed completely without major damage
to the surrounding neural tissue. Neurophysi-
ologic monitoring is helpful when operating
on intra-axial spinal tumors, sometimes also in
extra-axial tumors.
In spinal AVMs and dural AVFs we try to treat
the lesion by endovascular means first. If this
is unsuccessful, microsurgical removal follows.
The aim is similar as for intracranial surgery, to
obliterate the pathological vascular structures
but to keep the normal vasculature intact.
In these lesions we plan for a more cranio-
caudal margin of the dural exposure than in
tumors. It is important to be able to evaluate
the anatomical configuration of the whole le-
sion already from the beginning. ICG is often
helpful when distinguishing the various ves-
sels. The same strategy is applied for all the
spinal vascular lesions; we try to remove them
completely without disrupting the surrounding
neurovascular structures.
6.9.2. Positioning
The positioning for spinal intradural lesion
varies depending on the level of the lesion. In
positioning there are always two aims: (1) to
have an optimal working angle; and (2) to keep
the operative field well above the heart level
with minimal obstruction of the venous flow.
The latter point is very important in keeping
the intraoperative bleeding at minimum.
For cervical lesions the patient is placed in
prone position with the head attached to a
head clamp (Figure 3-7 - page 58). The neck
is flexed a little forward and the head is ele-
vated above the heart level. The table is placed
in anti-Trendelenburg position, and the knees
are flexed to prevent the patient from sliding
in the caudal direction. Two stiff cushions are
placed longitudinally in parallel fashion below
the thorax with a 10 cm gap in between. These
are meant to decrease the intra-abdominal
pressure, help the movement of diaphragm,
decrease the ventilation pressure, and increase
the venous outflow. The neurosurgeon stands
on the side of the patient working from the ip-
silateral side of the lesion.
For thoracic and lumbar lesions we prefer
to use the kneeling or so-called "praying to
Mecca"-position (Figure 3-9 - page 60). The
advantage of this position compared to the
prone position is, that the operative area can
be placed higher than the rest of the body
keeping venous pressure lower, resulting in less
intraoperative bleeding when compared to the
prone position. Old patients with concomitant
diseases may not tolerate the kneeling position
and normal prone position (without the head
clamp) has to be used instead. Also for lesions
at the levels of Th I and Th II the prone posi-
tion may be sufficient. The kneeling position-
ing starts by placing the patient first in prone
position, with the ankles just hanging over the
caudal edge of the operating table. Then one
person keeps the ankles or knees in place, while
two persons lift the upper torso upward and
backward. Unless the knees are kept in place
during this step, the patient will slide caudally
off the table. A specially designed, high, and
relatively stiff cushion is placed underneath the
sternum to support the whole upper body. The
cushion for supporting the upper body should
be designed so, that it leaves the belly hang-
ing free, keeping the abdominal pressure low.
Spinal intradural tumors | 6

242
In the final position the knees and hips are in
line and both are at about 70°–80° angle. A
trapeze–like support is placed to hold the but-
tocks in place. The patient should not be sitting
on this support; rather, the body weight should
be evenly distributed between the sternum, the
knees and the buttocks. Placing the knees in too
much flexion prevents venous outflow from the
thighs risking venous thrombosis. Side supports
are then adjusted to keep the knees from sliding
outward. A soft pillow may be placed beneath
the ankles to prevent pressure from the table
edge. The arms are brought forward and sup-
ported with armrests and pillows in such a way
that the shoulder blades are neither lifted up,
nor hanging. The brachial plexus region should
be left without compression. The head can be
kept either in a straight neutral position or
turned to side. Special head pillows are designed
for this purpose, but even a classical dough-
nut pillow works well. The important thing is
to make sure that the neck is not left hanging
or over-rotated. An appropriate number of soft
pillows is used to achieve optimal head posi-
tion. With the final head position one needs to
confirm that the eyelids are shut and that there
is an even pressure distribution on the face. The
head is not supposed to carry any extra body
weight. Finally, the whole table is tilted in such
a way that at the site of the planned approach
the back is almost horizontal.
We do not use low molecular weight heparin
to prevent venous thrombus during the kneel-
ing position, as seems to be the standard at
some other departments. Despite this, the risk
of thromboembolic complications has not been
any higher in our patients.
6.9.3. Approach
With the patient in position, the appropri-
ate level for the approach needs to be iden-
tified. For cervical and lumbar spine this can
be achieved easily with C-arm fluoroscopy.
For thoracic lesions we navigate according to
the previously placed methylene blue mark. A
longitudinal incision is planned at the midline.
The length of the incision varies depending on
the size of the lesion, especially on the cranio-
caudal length of the lesion. In small lesions a
2 to 3 cm incision is enough, in larger lesions
the length has to be adjusted accordingly. Also
the amount of subcutaneous fat affects the
approach, in obese patients with a longer dis-
tance to the spinal canal, the exposure needs
to be somewhat more extensive.
After the skin incision the subcutaneous fat is
entered. We prefer to use diathermia for linear
and sharp dissection. The wound is spread and
kept under tension with a retractor. It is better
to carry out a meticulous hemostasis through-
out the approach, since this prevents oozing
blood from obstructing the operative field. In
addition, closing becomes much faster, since
less time has to be spent on chasing after all
the small bleeding sites. Beneath the subcuta-
neous fat lie the fascial layer and the spinous
processes. Once one or several spinous proc-
esses have been identified, the level is again
checked with C-arm fluoroscopy, and the ap-
proach is adjusted accordingly. In case methyl-
ene blue was used, the targeted spinous proc-
ess is distinguished by the color.
During hemilaminectomy, we open the muscle
fascia at the midline on the ipsilateral border of
the spinous processes. Then we follow the lat-
eral wall of the spinous process, while stripping
the paravertebral muscle attachments with
diathermia until the actual vertebral lamina
is reached. The lamina is then exposed in the
lateral direction to the level of the pedicle. In
cranio-caudal direction the exposure is tailored
according to the length of the lesion.
One of the challenges in performing a multiple
level hemilaminectomy is selecting an optimal
retraction system. If the lesion is so small, such
that one or two level hemilaminectomy is suf-
ficient, a retractor for microdiscectomy can be
used. There are several designs available.
6 | Spinal intradural tumors

243
We prefer to use the Caspar microdiscectomy
specula retractor set. However, for larger hem-
ilaminectomies we have not yet found an opti-
mal retractor. We use the framed laminectomy
retractor, which is very powerful, but unless
the retractor blades are placed optimally, the
blade at the midline may obstruct the working
angle.
Once the appropriate laminas have been ex-
posed, we proceed by performing the bony
hemilaminectomy. This is done with a high-
speed drill. If the bone is expected to be thin,
we start immediately with a diamond tip, oth-
erwise the outer cortex and the cancellous
bone can be first removed with round cutting
drill before switching to a diamond drill. We
leave only a very thin bony shell against the
ligamentum flavum. The dura is then exposed
by removing the ligament together with the re-
maining bony shell with a Kerrison rongeur. It is
important to extend the exposure also over the
midline by drilling away the medio-basal part
of the spinous process.
With the dura exposed, the lesion is sometimes
already visible through the partially transpar-
ent dura. Also in case of DAVFs, one should be
able to see the enlarged epidural veins. Before
opening the dura, we place Surgicel along the
edges of the exposure to prevent venous ooz-
ing from the epidural space. The dura is opened
in a linear, longitudinal fashion. First, we make
a small cut with microscissors to penetrate
the dura. Then a blunt microhook is inserted
into this opening and pulled both cranially and
caudally to open the dura along its longitudi-
nal fibers. The arachnoid is kept intact during
this phase. The dura is lifted up with multiple
sutures, which are kept under tension. Finally,
the arachnoid membrane is opened in the same
longitudinal fashion and it can be attached to
the dural edge with a hemoclip.
6.9.4. Intradural dissection
The intradural dissection depends entirely on
the lesion. A common factor is the use of very
high magnification due to the small size of
all the structures. Also the suction is usually
exchanged for one with a smaller caliber, and
sharp bipolar forceps are often used. The le-
sion removal should be planned so that normal
neural structures are manipulated as little as
possible. In extra-axial tumors we first devas-
cularize the tumor and then try to separate it
from all the surrounding structures before the
actual removal. In intra-axial tumors we first
debulk the tumor before searching for the pos-
sible tumor edge as in ependymomas. All the
bleeding points should be taken care of imme-
diately. Even a small amount of blood obscures
easily the view down in the deep, and narrow
operative field.
6.9.5. Closure
Once the lesion has been removed the dura is
closed in one layer. This can be performed ei-
ther with a running suture (e.g. 6-0 or 7-0 Pro-
lene) or with AnastoClips originally developed
for vascular anastomosis. We do not close the
arachnoid as a separate layer. The dural closure
is further sealed with fibrin glue. Careful he-
mostasis is carried out in the muscle layer. The
muscle fascia is closed in a single layer with
dense interrupted sutures. Then subcutaneous
layer and skin are closed separately. We do not
use drains and there are no restrictions with
respect to mobilization.
Spinal intradural tumors | 6

245
Neurosurgical residency in Helsinki | 7
7.1. NEUROSURGICAL RESIDENCY IN HELSINKI
7.1.1. Residency program
The Neurosurgery Department in Helsinki is
the largest unit for training neurosurgeons in
Finland, where there are altogether five neu-
rosurgical departments in the whole country,
each department associated with university
hospitals in different cities. One professor,
several associate professors and one assistant
professor together with staff neurosurgeons
are responsible for training of the residents in
a 6-year program. EU recommendations con-
cerning the number of required procedures are
followed. All residents have a dedicated men-
tor representing different fields of neurosur-
gery changing every 6 months. In addition to
4.5 years of neurosurgery, the residents have to
do 3 months of neurology, 3 months of surgery,
9 months of general practice and the remain-
ing 3 months neuroanesthesiology or research.
To become a board-certified neurosurgeon one
has to pass the national examination making
one automatically EU eligible. The so-called
EANS-examination at the end of the 4-year
EANS training course program is recommended
to all residents or young neurosurgeons, but is
not compulsory as of now.
Academic dissertation of Dr. Martin Lehecka (right),
with Prof. Robert F. Spetzler, as the opponent (left), and
Prof. Juha Hernesniemi, as the supervisor (center).
List of residents trained during
Prof. Hernesniemi's time:
Jussi Antinheimo, MD PhD
Jari Siironen, MD PhD
Atte Karppinen, MD
Joona Varis, MD
Nzau Munyao, MD
Matti Wäänänen, MD
Kristjan Väärt, MD
Esa-Pekka Pälvimäki, MD PhD
Johanna Kuhmonen, MD PhD
Minna Oinas, MD PhD
Martin Lehecka, MD PhD
Riku Kivisaari, MD PhD
Aki Laakso, MD PhD
Emmanouil Chavredakis, MD
Miikka Korja, MD PhD
7. NEUROSURGICAL TRAINING, EDUCATION AND
RESEARCH IN HELSINKI

246
7 | How to become a neurosurgeon in Helsinki | Aki Laakso
7.1.2. How to become a neurosurgeon in
Helsinki – the resident years
by Aki Laakso
It is actually quite hard to tell why anybody
would want to be a neurosurgeon. Almost eve-
ry day you put yourself willingly, even eagerly,
into situations where your performance may
dictate the quality of life – or even the differ-
ence between life and no life – for another hu-
man being. When I look at my colleagues here
in Helsinki, I see an extremely wide variety of
different human personalities – everything
from a quiet, unassuming philosophical type
to extroverted, flashy connoisseurs of extreme
sports. What is common, however, is that eve-
rybody seems to love what he or she is doing.
My path leading to a neurosurgical residency
was probably not a typical one. I was rather
old, 32 years, when I started my training, and
had spent years doing research after medical
school. The field of my research was always
neuroscience, but it was still something that
seemed light-years away from drilling holes
into other people's heads. I have the great-
est admiration for science and scientists, and
should a thing or two in my life have happened
differently, I might still get my daily dose of
playing with neurons in the lab instead of in
the operating room. In 2003, I nevertheless
made the decision to put my medical school
education into use and become a physician
again.
So, why neurosurgery? I sometimes like to an-
swer with a story of a poll in which a large
number of American women were asked to
vote for the sexiest profession a man can have.
Racecar drivers turned out to be the hottest
guys, while brain surgeons came second on the
list. Since I am too tall to fit in a Formula one
car, I had no choice but… (Although heard by
many, the story itself must be an urban legend,
since nobody in the States gives a hoot about
Formula One races, and I find it very hard to
believe that many American girls would con-
sider NASCAR drivers that desirable…) The real
answer for me, however, is twofold: the human
brain and the consciousness arising within it
being the greatest mysteries of the modern-
day biology (and the brain is pretty much the
only organ I find interesting enough to devote
my career to – who would call a kidney or a
gut as "great mysteries of nature", even if they
indeed are small miracles of evolution?); and
my desire to train myself in a profession where
I can accomplish something meaningful us-
ing manual skills and knowledge that only few
people in the society have.
When I begun my residency, my previous ex-
perience in clinical medicine came from two
disciplines that are very different from neuro-
Dr. Aki Laakso

247
surgery: psychiatry and neurology. What unites
all three, however, is that they all are about
treating people's brains. For my generation, the
6-year neurosurgical residency in Finland con-
sisted of 4.5 years of neurosurgery, a total of
one year of neurology and some other surgi-
cal discipline than neurosurgery combined, and
six months of general practice in a municipal
health care center (the reason for that one
having everything to do with social politics and
nothing with the training itself). Many people
asked me in the beginning how I dare to start
a neurosurgical residency without any previ-
ous surgical experience, and did not hide their
skepticism when I told them that I do not share
their concerns, and feel that some knowledge
on clinical neurology will probably be way more
important and useful than a know-how to re-
move appendices. Today, after completing my
residency, which also included three months
of plastic surgery (which, for the record, was
a quite useful period), I still feel the same way.
The neurosurgical procedures, especially the
ones you perform early during your training,
are so different from anything you would learn
in any other surgical specialty, that I still do
not consider it mandatory in any way to try and
get a lot of experience in some other surgical
discipline before starting the neurosurgical
residency. However, the basic knowledge and
understanding of neurological signs, symptoms
and diseases was a tremendous help, at least
for me.
A typical day of a resident in the department
starts around 7.45 AM with ward rounds with a
senior staff neurosurgeon and nurses. Since the
current number of doctors usually allows for
two to three seniors and residents in each ward,
the resident rarely has to be responsible for
more than a dozen of patients. The paperwork
is usually the residents' chore, but its volume
is easily manageable (which may be difficult to
believe if you look at the piles of unfinished pa-
tient files some of us have been able to create
at some point of our junior careers!). Rounds
are quick and efficient (compared to 3-4 hour
rounds many of us has suffered at neurologi-
cal departments), and there's usually time for
the morning's first cup of coffee between them
and the radiology meeting which starts at 8.30
AM. The radiology meetings, where all imag-
ing studies done during the previous day are
reviewed together, are incredibly educational
and even entertaining occasions. Looking at
the results of your own operation with the au-
dience of your colleagues can lead to an emo-
tional state of deep satisfaction and reward
- or bitter self-torture and humiliation; both
of these extremes serve to make you a better
surgeon. Sometimes the debate about a certain
case may get heated, and especially younger
residents do wisely when they remember Dr.
Pentti Kotilainen's words: "A good resident has
big ears and a small mouth"!
Around nine o'clock or so, people start to dis-
sipate to their daily activities. Many go to the
operating room, but maybe twice a month a
poor resident has to face the most feared as-
signment of them all: the outpatient clinic. If it
happens to be the "resident outpatient clinic",
consisting of mostly trauma and shunt patient
follow-up visits with no first-time patients
coming for consultation, one can congratulate
him- or herself, since the day will likely be short
and rather pleasant. All too often, however, the
unlucky resident finds himself substituting for
a senior staff member, facing a horde of pa-
tients with bilateral acoustic schwannomas,
diffusely growing low-grade gliomas, brain
stem cavernomas, malfunctioning deep brain
stimulators, failed lumbar spine fusions and
spinal arteriovenous fistulas. I guess this will
remain a problem as long as the waiting list
for the outpatient clinic will be two to three
months like it is now, and the absence of a sen-
ior neurosurgeon cannot always be taken into
account when the patients are given the ap-
pointments. Naturally, the seniors will help and
consult with difficult patients, but many times
the situation is frustrating for both the resident
and the patient.
Aki Laakso | How to become a neurosurgeon in Helsinki | 7

248
Luckily, even after two or three days of out-
patients, the resident still has twenty days of
good and happy stuff each month: operations.
Each resident who has been chosen for train-
ing will have a senior mentor, changing in six-
month cycles. The resident may and should as-
sist his mentor in all operations, which usually
means a great front-row seat to see all the ac-
tion: all of our microscopes are equipped with
high-quality assistant eyepieces, enabling the
neurosurgeon and the assistant to share the
same magnified view. The sense of depth is not
comparable to what you get through the pri-
mary eyepieces, but the views are still superb.
Following 7-8 different seniors during your
residency gives you a great armament of tricks
and tips to build your own surgical technique
and style upon. The mentor will also be the
first one to consult with your own cases, and,
if necessary, will back you up in the OR should
you need guidance or help.
Yes, I mentioned own cases. No law in Fin-
land forbids a surgical resident to operate in-
dependently. Once you have learned a certain
procedure well enough, taught by seniors or
more experienced residents, it is common for
residents to operate on their own – even dur-
ing the night when the resident on call may be
alone in the hospital. I personally liked this a
lot, and I believe others have liked it as well.
It teaches you responsibility, ability to make
decisions independently, and builds stamina, or
"sisu", when you cannot immediately hand over
the instruments to someone more experienced
at each small obstacle. This is not to say that
the department's policy is to put patients at un-
necessary risk or to let inexperienced residents
to do whatever silly thing they think might be
"a great idea". There is a strong spirit that fa-
vors an extremely low threshold for consulting
someone more experienced, day or night. If you
end up doing a stupid mistake without consult-
ing anybody, you can rely on receiving prompt
feedback for that. If you feel that the senior is
not giving you a straight answer, or refuses to
scrub in to help you in the operation, it is prob-
ably because he or she knows your limits, trusts
you in that given situation (even if yourself do
not), and wants to encourage you to think and
act independently. A great deal of hands-on
teaching of surgical tricks, especially during
early phase of residency, comes also from the
experienced scrub nurses. Our OR nurses are
dedicated professionals assisting only in neu-
rosurgical operations, some of them with dec-
ades of experience, and having closely watched
thousands of operations. A smart resident
should display utmost respect for them, and
listen closely to valuable tips they have to offer.
The same truth applies also to our experienced
nurses in neurosurgical ICU and bed wards –
their "clinical eye" often easily outperforms
that of a young resident: please listen to what
they have to say and learn!
The number and diversity of operations one can
perform during the resident years depends ob-
viously a lot on the resident him- or herself,
but the total number of operations will easily
reach several hundreds. During the first half of
residency, you will probably learn shunt opera-
tions, traumatic brain injury cases, and some
simpler spine and tumor operations. During the
second half, your repertoire probably extends
to more difficult gliomas, small meningiomas,
a few posterior fossa craniotomies, more so-
phisticated spinal surgery (though most likely
not extensive instrumentations), maybe some
spinal tumors. And of course you gain gener-
ally more experience, more cases, all leading to
better results, more elegant surgical technique,
faster operations, improved self-confidence…
until you encounter your first really bad com-
plication, and immediately feel miserable and
rewound back to the starting point. Luckily, if –
or, rather, when – that happens, the colleagues
are very supportive, and from their own expe-
rience understand that there is no room for
accusations and cynicism, but constructive
re-evaluation of the case and circumstances is
probably desirable.
7 | How to become a neurosurgeon in Helsinki | Aki Laakso

249
A significant proportion of operative experi-
ence during one's residency comes during
on-call shifts, which usually take place two or
three times a month (the on-calls are shared
by eight residents and three or four youngest
specialists). On-calls may be really quiet, or you
may end up answering dozens of phone calls,
doing seven operations and struggling to find
a two-minute break for taking a leak. The on-
calls are not really scary, though, even for less
experienced young residents. You will always
have a senior backing you up, just a phone call
away, an anesthesiologist will be on-call with
you just for neurosurgical patients, and the
nursing staff is usually experienced and helpful
as well. You have probably also been "the day-
time on-call resident" for a few times before
doing nighttime on-calls, which gives you the
opportunity to train being on-call safely, with
all your colleagues around you to help.
You cannot become a good neurosurgeon just
by operating without building a strong theo-
retical background knowledge as well. All resi-
dents trained in Helsinki will attend the four-
year cycle of EANS (European Association of
Neurosurgical Societies) training courses, and
many younger residents not yet eligible for
EANS courses go to Beitostølen courses organ-
ized by the Scandinavian Neurosurgical Society.
The Finnish Neurosurgical Society will also or-
ganize an annual two-day course for all Finnish
residents. The department has a weekly meet-
ing schedule, and more likely than not, you will
give a talk there yourself a few times if you
enter the residency program. And of course you
have to read. And, finally, when you will take
the final exam to get your board certification,
you will have to read a lot.
All in all, I think I can honestly say that Hel-
sinki has been a great place to spend my resi-
dent years. The atmosphere in the department
is really friendly and supportive, and the large
catchment area for patients ensures a steady
flow of rare cases, as well as vast numbers of
patients with more common pathologies. Con-
tinuous presence of visitors from abroad and
other Finnish university departments ensures
that the "household ways of doing things" are
all the time susceptible to fresh influence, crit-
ical observation and different points of view.
And, if you are inclined to doing research, you
will get a lot of support for that, too.
Aki Laakso | How to become a neurosurgeon in Helsinki | 7

250
7.2. ACADEMIC AND RESEARCH TRAINING
7.2.1. PhD program
In Helsinki and Finland, there is a long tradition
of completing a PhD thesis before, during or af-
ter a residency program. Nowadays, it consists
of 3-4 papers in international peer-reviewed
journals, some 200 hours of classes passed,
together with writing and defending a PhD
thesis summary. The topic can be of basic or
clinical research or both combined. Of the 16
neurosurgeons in Helsinki, 13 have an MD PhD
degree. One fourth of the Finnish physicians
are MD PhDs. Typically, a post-doctoral period
is spent in research or clinical practice in some
recognized lab or department of neurosurgery
outside Finland to broaden the horizons and
obtain special skills to be brought back home.
7.2.2. Making of a PhD thesis in Helsinki,
my experience
by Johan Marjamaa
In Finland it is common for a medical doctor to
make a PhD thesis; at Helsinki University 65%
of all MDs do it. In order to be able to aspire
for a good position at the university hospital,
I also felt that it was necessary to make one.
As a fourth year medical student I was not yet
quite sure about my field of interest, but I im-
mediately got very excited when I heard that
the Neurosurgery Research Group was recruit-
ing new members. Without hesitation, I up-
dated my CV, wrote a detailed application and
sent it to Professor Juha Jääskeläinen, who was
the group leader at that time (before becom-
ing the Chairman of Neurosurgery Department
in Kuopio). To this date I don't know by which
criterion I was chosen, but later I have heard
that there were several other applicants. Also
a younger medical student, Riikka Tulamo, was
recruited. At that time the group consisted of
Professors Juha Jääskeläinen and Juha Hernes-
niemi, Doctors Mika Niemelä and Marko Kan-
gasniemi and PhD students Juhana Frösen and
Anna Piippo.
After six months we were assigned our own
projects. Riikka was helping Juhana in studying
inflammation in aneurysm wall samples col-
lected by Prof. Hernesniemi at surgery. Riikka´s
special interest became complement activation
in the aneurysm wall. My project became to
Dr. Johan Marjamaa
7 | Academic and research training | Johan Marjamaa

251
further develop endovascular treatment meth-
ods in our newly established aneurysm model
in rats and to improve MR-imaging methods of
experimental aneurysms. I was thrilled at the
project, since it gave me the chance to start to
learn microsurgical skills in addition to learn-
ing scientific approach and thinking as well as
manuscript writing, statistics and other scien-
tific methods.
The title of my thesis was to become "Micro-
surgical aneurysm model in Rats and Mice:
Development of endovascular treatment and
optimization of magnetic resonance imaging".
During the years I made more than one hun-
dred microanastomoses and performed coiling
of the experimental aneurysms which were
then followed up with a 4.7 Tesla MR-scanner
for lab animals.
Technically speaking, for the PhD, one needs to
complete three to four manuscripts about the
subject. The thesis book consists of a literature
review, a presentation and discussion of one's
own results, as well as reprints of the manu-
scripts. Moreover one needs to participate in
courses on research methods and attend meet-
ings as well as present own results. The project
usually equals five years of fulltime work. The
thesis book is finally reviewed and commented
on by two reviewers, who are professors spe-
cialized in the topic. In the end there is a pub-
lic defense where the PhD student defends his
thesis against the opponent, a respected pro-
fessor who more often than not comes from
abroad. The celebration party after the defense,
in honour of the opponent, is called "Karonk-
ka". This important and often anticipated part
of the project is seldom cancelled since very
few doctoral dissertations are any longer re-
jected at the time of the defense.
Since I was simultaneously studying and work-
ing in the clinic for most of the time, it took
me six years to complete my PhD thesis. During
the first two years I was still a medical student,
so at that time I could do research only during
evenings and weekends. But, since the medical
faculty highly appreciates research among stu-
dents, also Wednesday afternoons were always
dedicated for this purpose. The work did not
delay my studies, although it is quite common
that students take time off from medical school
if they are doing research simultaneously.
The facilities in the lab at Biomedicum Helsinki
are excellent, the lab is in the hospital campus
area and it was always possible to drop in even
for a shorter time. Collaboration with other
groups is easy because of good connections and
an open-minded atmosphere, but also since the
facilities are designed in an unenclosed way
with open lab spaces and plentiful meeting
rooms and social areas. Since it was common
that the days were long and the experiments
were finished late in the night, good accom-
modation is necessary. Affordable, rather new
apartments (with saunas!) for PhD students
were conveniently located at walking distance
from the campus area and Biomedicum.
After my graduation I worked full time for one
year in the lab. The funding in the Neurosur-
gery Research Group was exceptionally well ar-
ranged. Most PhD students in other groups did
not receive any salary from the group, but had
to rely on small personal scholarships. In Janu-
ary 2006 I started as a resident at the Helsinki
Neurosurgery Department. As a member of the
research group I had also already become fa-
miliar with most of the staff at the department.
During the next three years I worked in the
department but was at the same time doing
research. The department encourages research
and made it possible for me to take 1-2 months
off every year for my project.
Finally after six years, in May 2009, came the
day I had anxiously been waiting for, the day
of the dissertation and Karonkka. After finish-
ing the actual scientific work, I could never im-
agine how much there still was to do during
the last months before the dissertation. All the
administrative work, the printing of the book,
Johan Marjamaa | Academic and research training | 7

252
the reprinting of the book, the organizing of
the Karonkka party and, of course, the prepara-
tion of my talk and the defense. The evening
before was scheduled for minor preparations,
but I ended up decorating the Karonkka-party
venue until late in the night. The dissertation
itself remains in my mind as a rather pleasant
experience. My opponent Professor Fady Char-
bel did an excellent work in commenting my
results and discussing the subject as well as
future goals with me. I am honoured by how
relevantly he was prepared. The dissertation
was attended by my family, friends as well as
hospital staff and collaborators from the lab.
The Karonkka party was held in a nice atmos-
phere and great weather, and only one guest
was taken to the emergency room, only to
make good recovery.
I have been privileged to work in the Helsinki
Neurosurgery Department and Research Group
in many ways. The international atmosphere
with hundreds of visitors every year is very in-
spiring and at a very early stage I was given the
opportunity to travel to international meetings
to present my results. In those meetings I did
not need to be nervous since I had already been
discussing my work with many influential pro-
fessors visiting the department back home. In
addition to reputable professors, Helsinki was
and is also visited by many young promising
neurosurgeons from all over the world. I believe
it is a valuable asset to meet and discuss with
colleagues who are more or less in the same
stage of training as yourself.
7 | Academic and research training | Johan Marjamaa
Figure 7-3. List of international fellows and visitors from August 2010.

253
Microneurosurgical fellowship with Prof. Hernesniemi | 7
7.3. MICRONEUROSURGICAL FELLOWSHIP
WITH PROFESSOR HERNESNIEMI
Fellowships are available with Prof. Hernesnie-
mi to learn microneurosurgical techniques and/
or to do scientific work. It is recommended to
make a short one-week visit to be introduced
and see the department before being accepted
as a fellow. From 2010 on, an Aesculap Hernes-
niemi Fellowship of 6 months was founded and
will be announced twice a year in Acta Neuro-
chirurgica and Neurosurgery. Also shorter visits
(one week to three months) are possible, and
in fact they are the most usual ones. Fund-
ing for shorter visits should be arranged from
the home country. Around 150 neurosurgeons
from all over the world visit the Department
of Neurosurgery annually. Most neurosurgeons
trained in Helsinki during Prof. Hernesniemi's
time have also spent a year as his fellow after
completing their residency.
List of Prof. Hernesniemi's fellows:
Romain Billon-Grand 2010-
Ahmed Elsharkawy 2010-
Miikka Korja 2010-
Bernhard Thome Sabbak 2010
Hideki Oka 2010
Aki Laakso 2009-2010
Jouke van Popta 2009-
Mansoor Foroughi 2009
Martin Lehečka 2008-2009
Puchong Isarakul 2008
Riku Kivisaari 2007-2008
Stefano Toninelli 2007-2008
Özgur Celik 2007- 2008
Ondrej Navratil 2007- 2008
Rossana Romani 2007-
Christian N. Ramsey III 2007
Esa-Pekka Pälvimäki 2006-2007
Ana Maria Millan Corada 2007
Baki Albayrak 2006-2007
Kraisri Chantra 2005 and 2006
Rafael Sillero 2006
Reza Dashti 2005-2007
José Peláez 2005-2006
Ayse Karatas 2004-2005
Keisuke Ishii 2003-2004
Minoru Fujiki 2002-2003
Joona Varis 2002
Jari Siironen 2001
Mika Niemelä 2000 and 2003
Hu Shen 1998-2000
Avula Chakrawarthi 1999
Munyao Nzau 1999
Leena Kivipelto 1998

254
Figure 7-4. World map in the OR lobby with pins showing hometowns of many visitors to the Department.
7.4. MEDICAL STUDENTS
Each fall 120 new medical students begin their
studies at Helsinki University (founded in 1640
as The Royal Academy of Turku and moved to
the new capital Helsinki in 1828 after the city
of Turku was destroyed in The Great Fire). Dur-
ing their fourth year of studies they come to
the Department of Neurosurgery, divided into
smaller groups, for one week of training in
basics of neurosurgery. Each student attends
20 hours of teaching by senior neurosurgeons
at the wards, ICU and ORs. In addition, sev-
eral medical students each year write a thesis
for their MD degree on a neurosurgical topic.
These students are supervised by senior neuro-
surgeons of the Department.
7.5. INTERNATIONAL VISITORS
Helsinki Neurosurgery is a very international
training unit, having had altogether 1500 visi-
tors from all over the world for shorter or long-
er (fellows) periods since 1997 from all over the
world. At the same time, most neurosurgeons
from Helsinki have visited, done scientific or
clinical work at top units abroad.
7 | Medical students | International visitors

255
Some prestigious visitors:
M. Gazi Yaşargil, Zürich, Switzerland, and Little
Rock, AR, USA
Dianne Yaşargil, Zürich, Switzerland, and Little
Rock, AR, USA
Ossama Al-Mefty, Little Rock, AR, USA
Toomas Asser, Tartu, Estonia
James I. Ausman, Los Angeles, CA, USA
Peter M. Black, Boston, MA, USA
Fady Charbel, Chicago, IL, USA
Vinko Dolenc, Ljubljana, Slovenia
Shalva S. Eliava, Moscow, Russia
Ling Feng, Beijing, China
Robert Friedlander, Boston, MA, USA
Askin Gorgulu, Isparta, Turkey
Guido Guglielmi, Rome, Italy
Murat Gunel, New Haven, CT, USA
Jan Hillmann, Linköping, Sweden
Akihiko Hino, Shiga, Japan
Egidijus Jarzemskas, Vilnius, Lithuania
Yasuhiko Kaku, Gifu, Japan
Mehmet Y. Kaynar, Istanbul, Turkey
Farid Kazemi, Teheran, Iran
Günther Kleinpeter, Vienna, Austria
Hidenori Kobayashi, Oita, Japan
Thomas Kretschmer, Oldenburg, Germany
Alexander N. Konovalov, Moscow, Russia
Ali F. Krisht, Little Rock, AR, USA
David J. Langer, New York, NY, USA
Jacques Morcos, Miami, FL, USA
Jacques Moret, Paris, France
Michael K. Morgan, Sydney, Australia
Evandro de Oliveira, São Paulo, Brazil
David Pitskhelauri, Moscow, Russia
Ion A. Poeata, Iasi, Romania
Luca Regli, Utrecht, The Netherlands
Duke S. Samson, Dallas, TX, USA
Hirotoshi Sano, Toyoake, Japan
Peter Schmiedek, Mannheim, Germany
Renato Scienza, Padova, Italy
R.P. Sengupta, Newcastle, UK, and Kolkata, India
Robert F. Spetzler, Phoenix, AZ, USA
Juraj Steno, Bratislava, Slovakia
Mikael Svensson, Stockholm, Sweden
Rokuya Tanikawa, Abashiri, Japan
Claudius Thomé, Mannheim, Germany
Nicolas de Tribolet, Geneva, Switzerland
Cornelius A.F. Tulleken, Utrecht, The Netherlands
Uğur Türe, Istanbul, Turkey
Dmitry Usachev, Moscow, Russia
Peter Vajkoczy, Berlin, Germany
Anton Valavanis, Zürich, Switzerland
Bryce Weir, Chicago, IL, USA
Manfred Westphal, Hamburg, Germany
Peter Winkler, Munich, Germany
Sergey Yakovlev, Moscow, Russia
Yasuhiro Yonekawa, Zürich, Switzerland
Grigore Zapuhlîh, Chisinau, Moldova
International visitors | 7

256
7.6. INTERNATIONAL LIVE SURGERY COURSES
7.6.1. Helsinki Live Course
The annual Helsinki Live Demonstration Course
in Live Microneurosurgery, or shortly just the
Helsinki Live Course, has become the signature
course of Helsinki Neurosurgery over the past
decade. The course was held for the first time
in 2001 and has been continuing on yearly
basis ever since. The infrastructure, logistics
and program content have been evolving all
the time, but the original idea still remains; to
demonstrate complex neurosurgical live opera-
tions performed by true masters. The partici-
pants have the privilege to observe not only the
actual procedure, but also all the preparation,
discussion, planning, as well as the postop-
erative treatment, while interacting with the
whole team treating the patient. The neuro-
surgeons are ready to share their opinions and
thought process behind realization of even the
most complex surgeries. At the same time the
course offers laid-back interaction between
neurosurgeons coming to Helsinki from all
around the world.
Each year, during the first week(s) of June
about 50-70 neurosurgeons come to Helsinki
for the Live Course. They travel here to see Pro-
fessor Hernesniemi along with his staff and the
international faculty to tackle 20-30 complex
neurosurgical cases such as aneurysms, AVMs,
cavernomas, intrinsic and extrinsic brain tu-
mors, bypasses or spinal tumors. During the
first three years (2001-2003) the course par-
ticipants were fortunate to observe the seam-
less co-operation between Prof. Yaşargil and
Ms. Diane Yaşargil while performing excellent
microneurosurgical operations. During the later
courses the international faculty has included
such prominent neurosurgeons as Vinko Dolenc
(Slovenia), Ugur Türe (Turkey), Ali Krisht (USA),
Fady Charbell (USA), Rokuya Tanikawa (Japan)
and others, all of them performing state of the
art neurosurgical operations and discussing
about their surgeries with the participants.
The earlier versions of the Helsinki Live Course
lasted for two weeks; nowadays, due to better
infrastructure and organization the course has
been shortened to 6 days. The first day consists
of lectures on topics related to microneurosur-
gery and different intracranial and intraspinal
pathologies. During the subsequent five days
there are 6-8 live neurosurgical cases operated
each day simultaneously in three ORs. Each of
the cases is presented with all the appropriate
imaging studies and after that some of the par-
ticipants watch the surgery directly inside the
OR while others follow live image on screen in
the lobby of the OR together with commenting
and explanations from the faculty members.
In addition, there are short lectures or videos
between the live cases. The operative schedule
runs every day from 8 AM to approximately 6 PM.
In 2010 the Helsinki Live course celebrated its 10th
anniversary. The course has been organized in col-
laboration with Aesculap Academy since 2003.
Further information on the upcoming courses
can be found at www.aesculap-academy.fi.
Figure 7-5. Prof. Yaşargil operated on the Helsinki
Live Course during the years 2001-2003.
7 | International live surgery courses | Helsinki Live Course

257
Figure 7-6. (a) Participants of the Helsinki Live Course are observing three simultaneous procedures in
the OR lobby. (b) Prof. Juha Hernesniemi commenting on surgery he just finished. (c) Prof. Vinko Dolenc
is explaining his approach for the next case.
Helsinki Live Course | International live surgery courses | 7

258
7.6.2. LINNC-ACINR course
(Organized by J. Moret and C. Islak)
The first Live Interventional Neuroradiology and
Neurosurgery Course (LINNC) was held in 2007.
It evolved from the earlier Live Interventional
Neuroradiology Course (LINC) held every second
year in Paris, when the chairman of the organiz-
ing committee, Prof. Jaques Moret, came up with
the idea of involving both endovascular surgeons
and neurosurgeons in the same live demonstra-
tion course. Thus LINNC 2007 was formed, com-
bining live neuroradiological intervention from
Paris and live surgeries from Helsinki, all being
viewed by nearly 800 participants at the Car-
rousel du Louvre in Paris, France. Over the years
the LINNC course has become the benchmark
in live demonstration neurovascular courses in
the world. Every year at the end of May nearly
900 participants, both neurosurgeons and neu-
rointerventionalists gather together for three
days of lectures and, more importantly, obser-
vation and discussion of neurovascular cases
treated live in front of their eyes by experts
from Helsinki, Paris and lately also Istanbul and
Ankara. Since 2009 LINNC has become a joined
meeting with the Anatolian Course in Interven-
tional Neuroradiology (ACINR).
During the three course days the OR in Helsinki
is transformed into a TV studio with cameras,
monitors and cables filling all the empty space.
Each day three to four live surgeries are per-
formed in two ORs and broadcasted via satel-
lite to the lecture hall in Paris. The surgeries
are different vascular cases such as aneurysms,
AVMs, cavernomas and bypasses. Each opera-
tion is presented with live commentary on the
strategy, microanatomy and various techniques
employed during the surgery by faculty mem-
bers both in Helsinki and at the course venue.
The ambience in the OR during the course days
resembles that of a World Cup game with a lot
of anticipation, hectic time schedule and joy
out of good results. Success comes only through
involvement of the whole department where,
apart from the direct work in the OR, there has
to be seamless co-operation also with ICU and
the wards to carry out all the tasks in a very
tight time frame.
The LINNC-ACINR course is organized by Eu-
ropa Organisation. More information on the
upcoming courses can be found at www.linnc-
acinr.com.
7 | International live surgery courses | LINNC-ACINR course

259
Figure 7-7. (a) Camera setup inside the OR during the LINNC course 2009. (b) Dr. Martin Lehecka (left) directing the satel-
lite broadcast to Paris in a temporary TV control room built in one of the storage rooms of the OR.
LINNC-ACINR course | International live surgery courses | 7

260
7.7. PUBLICATION ACTIVITY
Over the last few years about 35 scientific pa-
pers have come out every year from the depart-
ment focusing on molecular biology and op-
erative techniques on aneurysms and natural
history of AVMs. Earlier, clinical series of he-
mangioblastomas, schwannomas and meningi-
omas were published in collaboration with pa-
thologists and molecular geneticists. The WHO
classification of meningiomas is based on Hel-
sinki series. Also, risk factors for SAH and natu-
ral course of unruptured aneurysms have been
studied with many classical papers published.
There is also an increasing activity on basic and
clinical research on functional neurosurgery as
well as some research on spine surgery, as well
as on cavernomas and dural AV fistulas.
During the past few years, the annual number of
articles from the Department published in inter-
national peer-reviewed journals has doubled:
2010: 32 2004: 17 1998: 14
2009: 30 2002: 13 1997: 13
2008: 28 2001: 19 2003: 12
2007: 31 2000: 21
2005: 16 1999: 18
In the Appendix 1 of this book, we have col-
lected a reference list of recent articles focus-
ing on microneurosurgical and neuroanesthe-
siological techniques and principles.
Figure 7-8. Doctoral theses from the Biomedicum aneurysm research group from 2006-2010.
7 | Publication activity

261
7.8. RESEARCH GROUPS AT HELSINKI
NEUROSURGERY
7.8.1. Biomedicum group for research on
cerebral aneurysm wall
The Department of Neurosurgery at Helsinki
University Central Hospital is one of the larg-
est neurovascular centers in the world treat-
ing about 500 patients a year with cerebral
aneurysms, AVMs, cavernomas and dural AV
fistulas. The department has published several
classic papers in aneurysm and SAH literature
concerning e.g. risk factors of SAH and tim-
ing of aneurysm surgery, as well as imaging of
cerebral aneurysms. With a busy clinic with a
lot of clinical research behind us, we now have
a great opportunity to try to find answers to
some clinical problems, utilizing basic research
conducted in Biomedicum. Our research group
in Biomedicum was established in 2001 and
has grown over the years having now four sen-
ior scientists, four research fellows and eight
PhD students. The group has studied the snap-
frozen fundi of cerebral aneurysms resected
after microsurgical clipping. We have shown
that before rupture, the wall of a saccular cer-
ebral artery aneurysm undergoes morphologi-
cal changes associated with remodeling of the
aneurysm wall. Some of these changes, like
smooth muscle cell proliferation and macro-
phage infiltration, likely reflect ongoing repair
attempts that could be enhanced with phar-
macological therapy. Our group investigates
the role of inflammation as possible causes
of cerebral aneurysms. We collaborate with
Yale Genetics & Neurosurgery to identify the
aneurysm gene among familial aneurysm pa-
tients treated in Helsinki and Kuopio, Finland,
and The Netherlands, Japan and Germany (see
www.fiarc.fi). We also have an experimental
aneurysm model to study occlusion of aneu-
rysms by endovascular means with the possi-
bility to use 4.7T MRA to compare the findings
with histology. The ultimate goal is to develop
more efficient ways to occlude the neck of an
aneurysm completely by endovascular means.
So far, three PhD thesis have been completed
from the lab group:
• Juhana Frösen, MD PhD: "The pathobiology of
saccular cerebral artery aneurysm rupture and
repair-aclinicipathologicalandexperimental
approach"in2006,discussedwithProf.Robert
Friedlander, Harvard Medical School.
• Johan Marjamaa, MD PhD: "Microsurgical
aneurysms model in rats and mice: develop-
ment of endovascular treatment and opti-
mization of magnetic resonance imaging" in
2009, discussed with Prof. Fady Charbel, Uni-
versity of Illinois at Chicago.
• Riikka Tulamo, MD PhD: "Inflammation and
complement activation in intracranial artery
aneurysms" in 2010, discussed with Prof.
Peter Vajkoczy, University of Berlin.
Research groups at Helsinki Neurosurgery | 7

262
7.8.2. Translational functional
neurosurgery group
A significant number of people are suffering
from medically intractable pain or neurologi-
cal and neuropsychiatric disorders resistant to
conventional treatments. Functional neurosur-
gery offers clinical methods of relieving severe
forms of some of these disorders. The most
common current methods used are epidural
medullary stimulation, deep brain stimulation,
cortical stimulation, and vagus nerve stimula-
tion. Even though these methods are shown to
be clinically effective and their use is increas-
ingly widespread, the mechanisms of action are
not well understood and the choice of targets
is not uniform.Our group focuses on studying
neuromodulation of clinically significant dis-
ease models and targets in preclinical models.
The aim is to increase understanding of the
mechanisms of neuromodulation and to pro-
vide hypotheses for clinical studies. The main
interests are experimental models of movement
disorders, obsessive-compulsive disorder and
depression and the neural targets used in the
neuromodulatory treatment of these disorders.
7.8.3. Helsinki Cerebral Aneurysm Research
(HeCARe) group
This group studying clinical aspects on cerebral
aneurysms was established in 2010 with five
senior scientists and six students. The group is
focused on subarachnoid hemorrhage, cerebral
aneurysms and their treatment. This includes
comprehensive pro- and retrospective analysis
of all aneurysm patients treated at the Depart-
ment of Neurosurgery. The data is collected
from the Helsinki Aneurysm Database that
currently includes 9000 patients, treated since
1932 at the department. Our database includes
information from all patient files and radio-
logical imaging studies.
7 | Research groups at Helsinki Neurosurgery

263
Figure 7-9. Helsinki Aneurysm Database in the making. (a) Drs. Riku Kivisaari and Hanna Lehto analyzing old angiographies
from past decades. (b) The reality of performing clinical research.
Research groups at Helsinki Neurosurgery | 7

265
Jouke S. van Popta | Visiting Helsinki Neurosurgery | 8
In this chapter we present memories of some of
the visitors and fellows who have spent longer
or shorter periods of time in Helsinki. These
texts are meant to provide useful information
and practical details for those neurosurgeons
planning to visit Helsinki in the future.
8.1. TWO YEAR FELLOWSHIP –
JOUKE S. VAN POPTA (ZARAGOZA, SPAIN)
8.1.1. Why to do a fellowship?
Why to do a fellowship in neurosurgery? I
guess there may be several different reasons
and it may well be that it is different for every-
one, but of course I can only speak for myself.
Fellowship means a period of medical training
after a residency. I received adequate and prac-
tical neurosurgical training in The Netherlands
and when I came to work in Spain I was eager
and very motivated to put all that I had learned
into practice. After an organizational change
in my department I got more surgical responsi-
bilities and that is why I decided to apply for a
fellowship. Further improving my surgical skills
and learning new surgical techniques would
not only benefit myself but also my depart-
ment and of course, most important of all, the
patients.
8. VISITING HELSINKI NEUROSURGERY
Dr. Jouke S. van Popta

266
8 | Visiting Helsinki Neurosurgery | Jouke S. van Popta
8.1.2. In search of a fellowship
I have a genuine interest in neurovascular
surgery, and there is still need and future for
"open" cerebrovascular surgery, also in the
community where I work. After having decided
to apply for a fellowship, I asked myself where
would I go? I wanted a department known for
its neurovascular surgery, where I could see a
high number of operative cases, and where I
would feel myself, if possible, also comfortable.
There were several options on my list and I de-
cided to check them all out and to take a look
before making a definite decision and commit-
ment. One of the options was the neurosurgical
department of Professor Juha Hernesniemi at
the Helsinki University Central Hospital.
8.1.3. Checking it out
I knew the name "Hernesniemi" from the book
by Drake et al., "Surgery of Vertebrobasilar An-
eurysms" that I saw when I was a resident. I
met him for the first time during a congress
and I went to listen to all his lectures and pres-
entations. I was not only very impressed by
what I heard and saw, but I also had a good
feeling about the man himself. I checked Hel-
sinki Neurosurgery out by going to the 2008
Live Course. At the end of the first day I already
felt that "this was the place" for me to be and
after a few weeks I made the definite decision.
My acceptance was confirmed in a letter stat-
ing I was "cordially invited for a cerebrovascu-
lar fellowship for a 6 months period" starting in
January 2008. Since that moment I have never
looked back! And needless to say that the other
options on my list were of no importance any-
more!
8.1.4. Arrival in Helsinki
The last weeks before my fellowship were quite
hectic doing my daily work and meanwhile pre-
paring and organizing everything for my stay in
Finland. An apartment nearby the hospital was
available but up to only a few days before my
arrival I still did not know where it was or how
I could get in. I began to worry. I pictured my-
self arriving late at night with a delayed flight
in Helsinki, standing with my luggage in the
freezing cold, temperatures low beyond im-
agination, heavy snow storm raging, no public
transport, walking over icy roads and through
dark deserted streets, with no apartment to go
to and all the hotels closed. But a last minute
emergency e-mail and great secretarial help
brought an end to all of these worries and a
couple of days later I arrived safely and on time
in the early afternoon at Vantaa airport and
within an hour or so I was sitting comfortably
in a warm apartment. It felt good!
8.1.5. The very first day
On the first day Juha Hernesniemi took me for
a round through the OR complex, the ICU's and
the patient bed wards. After a (very early) lunch
we sat in the lobby of the OR and he asked
me about my neurosurgical background, and
my professional and personal interests. He ex-
plained to me the structure and the content of
the fellowship, and he stressed the importance
of observation "which is severely underesti-
mated in neurosurgery", (the importance of) the
books of Yaşargil and Sugita, the knowledge of
neuroanatomy from the practical neurosurgical
point of view, to be able to visualize the whole
operation first "in your own mind", to practice
(and practice and practice), to watch and edit
videos of operations, the power of repeating
and of course the absolute necessity to operate
everything (everything) with the microscope. In
all the weeks and months I came to spend with
him in the OR, slowly and bit-by-bit, I started

267
to understand and could clearly see and expe-
rience for myself in all of his surgeries how true
this all was and is. Often I think back on that
moment and every time I realize that basically
he told me everything that there was to tell on
that very first day!
8.1.6. A day in the life (of a fellow)
I arrive just before 8 o'clock in the morning in
the hospital. I change into my surgical clothing
and then I go to OR 1. I check the operation
program. Next I will select the images of the
patient from the radiological workstation and
put the patient data into the memory of the
microscope. I check the microscope, the video
recording equipment, the video screens and
monitors, OR lamps and the lamp camera. Af-
ter intubation we start with the positioning of
the patient. Assisting here is needed, obligatory
and extremely important! The sterile surgical
field is prepared and I will take a last quick look
at the screens and lights. Then we scrub, take
our positions and off we go!
The number of surgeries varies but on aver-
age Hernesniemi will operate three cases a day
and when he is on call it will probably be even
more. Between surgeries I make notes of the
operations and write them down in my note-
books. At the end of the day we will look at
the surgical cases of the next day, discuss the
images and the surgical techniques involved.
At home I will study and read. I made a study
program for myself although sometimes it has
been difficult to stick to it because these days
in the life of a fellow are long and winding, but
at the end always good!
8.1.7. Assisting in surgery
Assisting in surgery is not easy, although it may
seem so. Juha Hernesniemi is the fastest sur-
geon I have ever seen and that is why assist-
ing him is even more demanding. So you better
become quick and swift yourself! But is also
the best and fastest way to learn because it
keeps you on your "surgical toes" so to speak!
During the operation I concentrate on the real
Figure 8-2.

268
live neurosurgical anatomy which is unfolding
before my eyes, on his surgical technique and
I try to predict his next surgical move. When
not looking through the side tube of the mi-
croscope I prefer to stand to his right side in
a somewhat postero-lateral position so I can
simultaneously see him, the scrub nurse (and
not be in her way!) and the video screens. His
surgeries are of the highest level and that is
why he needs all the support and should be as
comfortable as possible.
8.1.8. Nurses
These surgeries could not be performed and
their high level not maintained without the
assistance of the OR nurses of the neurosurgi-
cal department. I have been to and seen neu-
rosurgical departments around the world but I
have never seen better OR nurses than here in
the Helsinki department. Professor H. may not
be the easiest person in surgery (he will be the
first to acknowledge that), but even in the most
difficult cases their professionalism and sup-
port stands out for everyone to see. This also
holds true for the nurses of the anesthesiologi-
cal department: their work seems less visible
from our surgical point of view but that does
not mean that it is less important!
8.1.9. Anesthesiologists
When I was a medical student I did a project
in anesthesiology so at an "early medical age" I
came to see the whole operation theatre from
the anesthesiological side of the stage. Anes-
thesiologists and surgeons should form a team,
because they cannot work without each other.
High-level neurosurgery of course demands
and requires high-level neuroanesthesiology.
Without a doubt, this is given and cared for,
in the OR and in the ICU's, by the anesthesi-
Figure 8-3.

269
ologists here in the neurosurgical department
of HUCH. About their techniques and tricks is
written elsewhere in this book, so read it and
invite your own (neuro)anesthesiologists to
come and visit!
8.1.10. Music in the OR
Hernesniemi operates with the radio on. He
prefers a certain channel with the music on
a certain volume. I very much love music and
that is why in the beginning I was pretty much
disturbed by this radio although I tried hard not
to pay attention to it. But there is a reason for
the radio. It provides some kind of background
music or "muzak" and this, I admit, works rather
well. Without it the OR would be far too silent
and serious music would make the ambience
indeed too serious, which of course does not
mean that we are not serious during surgery!
These radio channels tend to repeat the play-
lists of their songs so after more than one year
I believe that I have heard them all, and some
of them have even become favourites by now!
8.1.11. Rounds
Every week Hernesniemi will do the rounds
with his fellows and visitors. Sometimes we
skip one week (or two), but that is because of
heavy operating schedule. He will take us first
to the ICU's and the patient wards where will
see the patients who were operated upon and
we discuss their clinical evolution. If there are
new visitors, we extend the round to visit the
neuroradiological angio suite, and we will make
a stop to see the plaque in honor and memory
of Mannerheim, who founded the hospital, and
the portraits of Snellman and af Björkesten,
the first pioneering neurosurgeons in Finland.
I like these rounds very much and it reminds
me that doctors care for patients and that we
Figure 8-4. The monument of Jean Sibelius near Töölö Hospital.

270
Figure 8-5.

271
work for them. Hernesniemi will also tell about
the history of the hospital and the neurosurgi-
cal department, which in a way is also his own
history. There are many good stories being told,
so lend him your ear and take a listen!
8.1.12. Visitors
Juha Hernesniemi believes in an open-door
policy. That means that everyone is (cordially)
welcome in his department to come and take a
look and that there are no secrets in relation to
the surgeries and the surgical techniques. The
excellence of his surgeries is known through-
out the world and that is why visitors from all
around the globe come to visit his department.
All of them are different regarding their back-
ground, culture, experience, etc., and they form
a colourful group from humble and shy medical
students to well known neurosurgeons in the
field. There is much to tell about these visitors,
but the majority of them are polite, interested,
and respectful. There are also exceptions of
course, but that is a different story!
8.1.13. Pins and their stories
That the visitors indeed come from all around
the world is something you can see for yourself
when you take a look at the big world map near
the lobby of the OR complex. Every visitor is
kindly asked to place a coloured pin in the map
that corresponds with the city where she or he
is working. Europe, the United States of Amer-
ica and also Japan are very well represented.
Sometimes I look at the map and I wonder
what their stories are, because in a way every
pin has a life and a story of that life attached
to it. Some pins stand out for being the only pin
in a certain country and I call these the "lonely
pins". They almost always represent a colleague
from a far away country who took the effort
(and sometimes had to make the necessary fi-
nancial sacrifice) to come all the way to visit
the neurosurgical department in Helsinki. Visi-
tors are also asked to write something about
their stay in the guestbook, and there you will
find many interesting commentaries, also from
many famous neurosurgeons!
8.1.14. LINNC and Live Course
The LINNC and the Helsinki Live Course are very
special and important events in the year for the
department. They also mean a big logistical, or-
ganizational and surgical stress for all involved,
so we have to be at our best! During the LIN-
NC Hernesniemi performs live neurovascular
operations which are linked by satellite to an
important endovascular congress elsewhere.
During the Live Course 40 to 60 neurosurgeons
from all around the world come to Helsinki to
see and watch during one week Hernesniemi
perform a high number of neurovascular op-
erations and operations of skull base and
cerebral tumors. Also invited are well known
neurosurgeons from abroad who will also per-
form, at the same time in different OR's, special
operations for which they have become known.
All these operations are projected onto video
screens inside and outside the OR's and record-
ed. All the surgical interventions are pre- and
postoperatively discussed and explained by all
the participating surgeons, so you can learn a
lot! This amazing course had me glued to my
chair every day when I came to see it for the
first time. The Live Course is also a good oppor-
tunity to meet and contact other colleagues;
there is a very nice course dinner, and an in-
triguingly interesting party in the evening of
the last day (there is no excuse for not attend-
ing!).

272
8.1.15. Weather and the four seasons
When one thinks of the weather in Finland
maybe the first associations which come to
mind would be snow and ice, very low temper-
atures, long and dark winters, and short sum-
mers. The winter seems certainly long and dark,
and although the average temperatures may
be lower than you might have wished for, you
get used to it. Finns say that there is no bad
weather, only wrong clothes. The snow makes
for a beautiful sight in the streets and parks,
and Helsinki life is not in the least disturbed
by it. The sea is frozen and you can walk on
it, which seems so strange that it may be dif-
ficult to believe or imagine. Spring is amazing,
when nature starts to open up and blossom in
just over two weeks time. Summer is relatively
short but very nice. The temperatures are very
agreeable (not too cold, not too warm) and on
the many sunny days it seems as if almost all
in Helsinki are in the streets and on the ter-
races enjoying the sunny weather. Another
good reason to take a look! Autumn is very
beautiful, especially because of the changing
of the colour of the leaves. A curious experi-
ence is the delusion of time sense, which oc-
curs in the winter and the summer. During the
darkest months December and January it feels
like late in the evening when it is only still early
in the afternoon, and in June and July, when
the days are long and the nights are short, you
tend to wake up automatically very early in the
morning.
Figure 8-6.

273
8.1.16. Apartments
My apartment is small, but nice and clean, and
most important, it is quiet, and so it is good for
studying, reading and resting. It has become
my home for the time being. I spend almost all
of my time in the hospital or in my apartment
and maybe that seems abnormal but I decided
for myself to dedicate as much time as possible
to my fellowship. I know myself well enough
to realize that I also need to disconnect from
the work and that is why I prefer to take some
time off during the weekend and do something
different not related to neurosurgery. I have an-
other apartment, my real home, and I kept it on
purpose. It is important once in a while to go
back home and be in your own environment again
and reconnect with your friends and family.
8.1.17. Helsinki
I like Helsinki very much! The city is surrounded
by the sea, which makes it very special. It is
clean and quiet, there are many green spaces
like parks and trees, and the people are really
nice. If you consult a good travel guide you will
see that the city has a lot to offer and you will
surely find many things of interest and to your
liking.
Helsinki, because of its size, it is also an ide-
al place for walking, for example around the
Töölönlahti, downtown along the Esplanadi to
Kauppatori, or through the Kaivopuisto park
and along the seaside. Take a walk and see for
yourself!
8.1.18. Finnish food
As I spend a lot of time in the hospital I also
take my meals in the hospital restaurant. The
food is excellent with a great variety of soups,
salads, meat, fish, vegetables, pastas, rice, de-
serts and bread. I cannot read the Finnish menu
but I have never been disappointed! And when
I have some difficulties with certain combina-
tions I take a look at someone's plate and that
usually tells me what to do. Especially recom-
mended is the blueberry pie! Take a bite!
8.1.19. Languages
Finnish is considered to be a very difficult
language and that, even for those with a gift
for languages, it takes two or more years to
be able to speak and understand it fluently. In
the hospital everyone speaks English so learn-
ing Finnish is not a requisite to do a fellow-
ship in this department. I nevertheless made a
list of names of the surgical instruments (that
was kindly translated for me), so in the OR I am
Figure 8-7.

274
able to communicate also in Finnish during the
operations. Finland is bilingual (Swedish being
the other official language) and with a combi-
nation of German and English it is not impos-
sible, within a given context, to understand the
Swedish words. In Finland you will not be lost
in translation!
8.1.20. Famous words
They say that Finnish people are not so talka-
tive, but what does this mean? Not so talka-
tive, compared to whom or what? Compared
to your own culture, to your own people, or to
yourself?
Is there some standard that dictates how many
words you should say or speak in a given time
period, or use in a sentence or during a conver-
sation? Maybe someone who is not so talkative
only seems to be so, or has really nothing to
say at that moment, or knows that it is just
not the right moment to say something or to
speak, or communicates in a different way that
you maybe don't know or understand. Here are
some famous words and expressions spoken
by an equally famous Finn: "no niin", "which
side?", "where is the aneurysm?", "which kind
of tumor?", "pää nousee", "pää laskee", "pöytä
nousee", "pöytä laskee", "light is not good",
"tight! tight!, it is not tight!", "good trick!", "oh,
my goodness!", "you're left handed?!", "terri-
ble!", "which year?", "good case!", "this is im-
portant!", "we could manage!".
8.1.21. Practice, practice, practice
Hernesniemi told me that during microneu-
rosurgical operations it is very important "to
concentrate", "to isolate yourself", "to go step-
by-step" (like reading the story in a comic book
image-by-image), and "not to try to want to
go too fast". He also stresses the importance
of practicing because microneurosurgical skills
have to be learned and trained. In the rear of
the OR complex is a microscope for practicing
which also has a mouthpiece attached to it. I
started with suturing gloves, every time with
finer sutures and under a higher magnification,
and gradually for longer periods of time. There
is also a model that is used for practicing by-
pass surgery and in the supermarket I bought
some chicken parts, took the vessels and start-
ed suturing and "bypassing". Professional mu-
sicians practice their instruments, and there is
probably no end to practicing. Maybe (neuro)
surgeons should do the same?
8.1.22. Video editing
All of Hernesniemi's operations are recorded on
the microscope and on high-definition vide-
otapes. You can watch these tapes as many
times as you like (there are no surgical secrets,
remember?), download and/or edit them for
your own use (on condition of anonymity of the
patient data, of course). Video editing forms a
part my study program and I make my own
personal archive of his operations that I can
consult in the future for my own work.
8.1.23. The surgery of Juha Hernesniemi
This book is about the surgery and the surgical
techniques of Juha Hernesniemi. In a way his
surgeries speak for themselves, but of course
there is so much more to tell and write about
it, and that is done elsewhere in this book, far
more eloquently and better than I could ever
do. To watch him operate is a truly unforget-
table experience and the excellence of his sur-
geries is unparalleled. This was acknowledged
publicly, for everyone to hear and read, by a
world famous leading neurosurgeon who came

275
to visit the department. To me it is not only his
surgical technique, but also his great experi-
ence, his positive attitude, his unbreakable for-
ward fighting spirit, and the human that makes
him unique. And that is why I consider him to
be the best!
8.1.24. The choice of a fellowship
The success of a fellowship depends for a large
part on ones own attitude, but of course the
department where you actually will realize
your fellowship is even so important, especially
if you plan to stay for a longer period of time.
My decision to come to the neurosurgical de-
partment of HUCH was not only a "cerebral"
decision, but also a decision of the heart. The
high number of neurovascular and tumor op-
erations, the excellence of the surgeries, the
open-door policy, the genuine feeling that you
are welcome and the willingness of everyone
(yes, everyone) to listen and explain, makes
this department the perfect place to come to
learn and an obvious choice for a fellowship.
So come and take a look!
Table 8-1. Key elements of the Helsinki fellowship
• Observation of surgeries
• Assisting
• Closing (under the microscope)
• Discussions (pre- and postoperatively)
• Rounds (ICU and bed wards)
• Reading (library in the OR lobby, with
textbooks and journals)
• Preparation of scientific papers and
presentations
• Video editing
• Practicing of microsurgical skills under
microscope

276
8.2. ADAPTING TO FINNISH CULTURE
AND SOCIETY – ROSSANA ROMANI
(ROME, ITALY)
"Consider your origin: you were not born to live
like brutes, but to follow virtue and knowledge"
(Dante: The Divine Comedy, Inferno, Canto XXVI, lines
118-120)
One of my esteemed Italian colleagues, who
was working in Florence, advised me to go to
see Prof. Hernesniemi because, he said: "He is
the best". I visited Professor Hernesniemi for
the first time for a period of two weeks, in Au-
gust 2006. I was very impressed by him, as well
as by his staff and I decided to interrupt my
work in Italy and to come to Finland in June
2007 to learn microneurosurgery.
8.2.1. The difference between "to talk the talk"
and "to walk the walk"
WhenIarrived,Ispentalmosttwomonthstrain-
ing under the microscope and in the beginning
it was difficult. I was very slow and awkward
but after a few months I became better and
faster. I also studied the basic neurosurgical
books recommended by Professor Hernesniemi.
Also, knowledge of the Finnish language made
it easier for me, from the beginning, to under-
stand in a faster way several of the microsur-
gical steps and the use of the surgical instru-
ments. However, to understand Hernesniemi's
surgical style one needs time and knowledge,
and only after assisting in many cases you real-
ize what he is doing, and how well-thought his
microneurosurgical techniques are. We record
all operative videos and we edit most of them.
Professor Hernesniemi has been very nice to
me and supported me - but at the same time
very demanding. If I was not a hard worker
with good results I would not have been able
to remain so long time. During my stay I have
assisted him in 1182 cases (677 vascular cases,
426 tumors and 79 others) and learned the
anatomy. I have made a personal file of my
whole experience here, and this is an experi-
ence I can always refer to and take a look in the
future. I have edited numerous videos for our
publications, and by doing that, learnt a lot. To
watch and edit operative videos is the modern
way to learn microneurosurgical techniques,
better than any neurosurgical book. When you
are young, you have to "steal and store" your
experience. I had also the chance to operate
one patient with two aneurysms.
Dr. Rossana Romani
8 | Visiting Helsinki Neurosurgery | Rossana Romani

277
Being close to Finns all the time I learned to
listen. It is difficult to know, which of the few
words said by Professor Hernesniemi are teach-
ing, and which are not. Many times he says:
"I'm teaching you". Finnish attitude is very ed-
ucative and teaches how to work in an efficient
way without losing time in useless small talk.
Many times I heard Prof. Hernesniemi to say:
"It is different to talk the talk than to walk the
walk". In Italy we say: "Between saying and do-
ing there is a sea".
Finnish neurosurgeons are efficient. They do
not lose time talking about what they have to
do because they know very well what to do and
they just do it. They can do the rounds, have a
meeting, perform surgeries and research, all of
that between 7 AM and 3 PM, and after that
they relax with their families or hobbies. Every-
thing is perfectly organized and it works.
In the OR nurses are doing their job in an ex-
cellent way. Only the essential instruments are
displayed and for all intracranial lesions (vas-
cular or neoplastic) the instrument set is almost
the same. The most impressive is to see how all
staff work together and even in difficult opera-
tions nobody loses control.
Besides the microneurosurgical activity and
the microscope training there is another im-
portant work: the paperwork! Professor Her-
nesniemi is speaking of his own experience:
"If you don't publish you perish!" You can be
the best neurosurgeon in the world but with-
out publications and scientific papers nobody
will know you, and you will not have the power
needed to make changes and improvements in
your local neurosurgical community. Scientific
paperwork is demanding and it requires a lot
of time besides the surgical activity, but on the
other hand it increases your knowledge. "Be-
hind all aneurysms lies the truth", Professor Da
Pian, a former chairman of the neurosurgical
department in Verona, once said, and I would
paraphrase his words as follows: "Behind every
scientific paper lies the truth". When you study
a topic of which you know everything, the
weak as well as the strong points, you begin
to realize that your contribution can improve
the knowledge available to the scientific com-
munity. When I arrived, Professor asked me to
rewrite some papers and after that I started to
review all the meningioma cases. Professor is
one the best not only in cerebrovascular surgery
but also in tumor surgery, especially in menin-
giomas. Contrary to vascular cases, which, in
many neurosurgical departments, especially in
Italy, are an exclusive area of the chairman
of the department, meningioma surgeries are
performed by a large number of neurosurgeons,
and this was the reason why I became inter-
ested in them.
I learned how to do a scientific paper, from the
collection of the data to the discussion, and I
have prepared many successful publications
(more than 20) and book chapters (more than
6), not only on meningiomas but also on vas-
cular surgery. I'm having a great opportunity
to work here and to learn from Professor Her-
nesniemi.
In Italy I was not happy about what I was
learning, especially in terms of microneurosur-
gical techniques. Many young Italian scientists,
researchers and doctors go abroad to work and
many never come back.
The initial plan was to stay one year doing a
cerebrovascular fellowship, but during my stay
I worked so hard and I got good results that I
was offered the opportunity to prepare the PhD
thesis. I'm now actually involved in the proc-
ess of writing it and day by day I'm getting a
different "forma mentis", a different state of
mind, "the Finnish attitude to work".
Rossana Romani | Visiting Helsinki Neurosurgery | 8

278
Figure 8-9. Tower of the Helsinki Olympic Stadium

279
8.2.2. Difficult to learn but good for life:
The Finnish language
When you grow up in a country where you
study Latin at school and where you study only
languages originating from Latin you think
that all European languages are based on Latin
- but this was small Italian thinking. Finnish is
just Finnish coming from… Finnish.
Many neurosurgeons visiting Helsinki Neuro-
surgery, and coming from all over the world,
were very impressed by my knowledge of Finn-
ish. Almost all of them asked me: “Why did you
study Finnish? Do you want to live here all your
life? Do you have a Finnish boyfriend?“ In their
questions they were looking for a reasonable
explanation why someone would undertake the
study of such a difficult language.
I didn‘t study Finnish because of the hand-
some Finnish male; at least not in the begin-
ning when I didn‘t know that the most beau-
tiful neurosurgeon in the world was Finnish. I
studied Finnish because I was interested, since
the beginning, in Finnish culture and Finnish
people. And to know people, to bond with them
and their culture you have to speak their own
language.
When you see written Finnish for the first time,
you think that somebody, seated at the com-
puter keyboard, wrote a random mixture of
characters. The most difficult is to understand
where one word ends and the next one begins.
Before studying Finnish I thought that German
with four cases and a logical construction of
grammar and syntax was the most difficult
European language, but compared to Finn-
ish, it was an easy language to learn. Finnish
language has 15 cases and no prepositions or
articles, making the construction of sentences
a challenge.
I asked my Finnish friend whom I met in Flor-
ence before coming to Finland, how to trans-
late “buonanotte“ and she answered, smiling:
“It is very difficult to pronounce“, and contin-
ued: “Finnish is very difficult, almost impossible
to learn“. That was incredibly true and to say
“hyvää yötä“ - that means “buonanotte“ - was
extremely difficult because you have to speak
and breathe at the same time. Italian language
is spoken in the lips, Finnish in the throat.
But the problem of the Finnish language is that
after going to the language school at Helsinki
University, after many courses and sacrifices,
I realized that the language you need in your
daily work is altogether another language. The
spoken language is different from the official
one studied at school, and this completely de-
stroys you.
To study Finnish is like to run a marathon or
to climb a mountain …you should not give up.
Finnish is a rich and beautiful language and it
is not impossible to learn. If I did, everybody
can.
Studying Finnish completely changed my life in
Helsinki, in Finland and in the OR. This is be-
cause when you speak to Finns, especially in
the beginning, in their own language they feel
happy and they like you despite your poor Eng-
lish or your whimsical Latin temperament. I will
never forget my first Pikkujoulu (a Christmas
party where there is much alcohol and happi-
ness), when one of the OR nurses told me: “We
like you very much“. In vino veritas and I was
very happy because that was true.
Many times I changed the rules. If I would be
in my neurosurgical department in Italy and

280
a foreign neurosurgeon would be visiting the
department, I would be very happy to hear my
own language especially if it had been very dif-
ficult to learn for him or her. When you learn
a language you discover a new world, because
you can live close to the people and share a life
with them, and this is something that no books
or pictures can give you.
8.2.3. When in Finland do as the Finns
My first week in Finland was terrible because
I was alone in a new culture and a new coun-
try. I lived my first month in Helsinki with a
Finnish family, and after a while, I became
their fourth daughter. Thanks to them and their
support I learned all Finnish habits very fast.
Everything was different from my Italian cul-
ture, but “different“ does not mean worse. You
cannot compare a Mozart symphony or a Raf-
faello painting with a beautiful flower or with
a summer sunset. Beauty has different faces.
A Roman proverb says: “When in Rome do as
the Romans“ (Sant Ambrose, 387 A.D.), and this
was what I did in Finland.
I discovered Finland as a beautiful country. Liv-
ing with my Finnish family allowed me, since
the beginning, to go to a summer cottage
where you live in the middle of nature. I had a
sauna close to the lake and I thought to myself,
how lucky Finnish people are to be delighted
by such beautiful scenery. I took a bath in the
sauna and I went for a swim in the lake. I cel-
ebrated Juhannus, the astronomical midsum-
mer, the shortest night of year, with my Finnish
family and friends in their cottage. I realized
that in Finland there is a great respect for na-
ture and animals. In the countryside, immersed
in nature, I could understand the Finnish at-
titude much better.
If you come from a country with several million
inhabitants and you are used to talk everywhere
with everybody, you will note a completely dif-
ferent world in Finland. The Finnish concept of
politeness is different compared to most other
countries. Especially in Italy, it is considered
polite to communicate. In Finland it is polite to
leave people alone. This explains why they are
so quiet and silent everywhere. This aspect of
Finnish culture impressed me very much. I had
never before been in a silent crowded tram and
never studied in the same room with ten nurses
talking to each other. This is impossible to expe-
rience in Italy where there is noise everywhere.
In Finland even in the football stadium during
a match the atmosphere is quiet, safe and si-
lent compared to the confusion and sometimes
dangerous atmosphere of the Olympic stadium
where I used to go in Rome.
Finnish people are quiet, but to be quiet doesn‘t
mean that they are weak. Finns are strong peo-
ple and in sport you can see their attitude. Fin-
land has many important athletes, not only in
Formula One but also in high-speed downhill
skiing, cross-country skiing, long-distance run-
ning, rowing and the most important Finnish
sport: ice hockey. This is like football for Ital-
ians. People go crazy for this sport. Recently
Finland won the Olympic bronze medal, com-
ing after Canada and USA. This victory was very
important, especially since neither Russia nor
the loved-hated Sweden got a medal. Finland is
the best European country in ice hockey. Eve-
rybody does sports. Even at -15 °C, with ice
on the street, or on a windy or rainy day, you
can see someone who is walking or running or
cycling. I used to do sports and here in Finland
I started to practice cross-country skiing and
also skating on ice. It is an incredible experi-
ence to walk or skate on the frozen sea. It is
fascinating, and also emotional at the same
time, especially for me coming from Southern
Europe.
What I liked and I learned in Finland is honesty.
When you come from a country where dishon-
esty is more common than honesty, you note
immediately that in Finland it is exactly the
opposite. A Chinese fellow once forgot an ex-
pensive camera in the OR pants, and after two

281
months his camera came back from the laun-
dry. In Italy it would be rare to get back some-
thing that was lost. The Finnish attitude to be
honest is in their blood. They are honest in their
work and everybody works hard during working
time. The honesty is in the respect for nature,
animals and all common things. Everything is
clean and everything is respected. I learned and
I‘m still learning a lot working with Finns.
8.2.4. Never good weather
I learned very fast that Finns love their country
and love to hate it. More than anything else
they complain about weather. Climate is a hard
task and Finns complain about it almost eve-
ry second. I was waiting terrified for my first
Finnish winter since June 2007, when I arrived
in Finland. I was very disappointed when I real-
ized that the winter, at least in Helsinki, is not
as terrible as Finns say. I remember my Italian
winters when I went to the hospital in Rome in
the darkness of the morning and got out in the
darkness of the evening. The difference in the
amount of light is not as big as Finns say, and I
didn‘t suffer for the lack of light. In the winter
you can ski or skate on the sea and you can en-
joy the beautiful white landscape. The atmos-
phere is magical and makes everything like a
fairy tale. I really liked the Finnish winter.
What is different in Finland, and Finns are proud
of that, is the summer. The light of the sum-
mertime shocked me, because there was too
much of it. In summer the darkness disappears
and if you wake up at three o‘clock in the night
the sun is already high in the sky. The stars dis-
appear for a few months. This strong contrast
between winter and summer makes the winter
seem to be dark, but in truth it is not.
The weather is something that every Finn com-
plains about. If in the winter there is no snow,
they complain for the lack of snow. If there is
snow and everything is light they complain
Figure 8-10.

282
Dr. Leena Kivipelto

283
about the snow and finally when the summer
comes they complain about summer too: too
cold or too warm! Finnish people are never
happy about the weather. The first words that
a foreign neurosurgeon learns in the OR is: “voi
voi, voi, voi…“, which is just a way to complain,
often without a true reason. I can understand
that weather was a problem for Nordic coun-
tries in the past, but nowadays it is not any-
more and winter is not so terrible compared to
Southern Europe.
8.2.5. Finnish attitude: “Sisu“
Working with Prof. Hernesniemi, I understood
very well what makes Finns so special. It is
something called “sisu“. It is difficult to trans-
late, but to see Prof. Hernesniemi performing
four or five difficult operations in one day, you
understand what sisu is. How Finns could man-
age during the Second World War is because of
sisu. Sisu is a kind of force inside the Finnish
gene, like a strong attitude that gives the abil-
ity to perform beyond the human capabilities.
I can understand very well how Finnish people
could manage against the huge Soviet Union
and how they retained their independence,
thanks to their “sisu“.
8.2.6. He and she = hän
In the Finnish language there are no separate
words for “she“ or “he“, there is only “hän“.
Finland is a matriarchal society and to me this
explains why it is an advanced country. Here
women got the right to vote in 1906, compared
to Italy, where women obtained it 40 years lat-
er. The current president is a woman. Finland is
a democratic country and there is equality be-
tween women and men. Even priests in Finland
can be women.
In the neurosurgical department I was very im-
pressed by the microsurgical operations of the
female senior neurosurgeon Leena Kivipelto.
She performs cerebrovascular operations, by-
pass surgery and many other neurosurgical
procedures. Watching her explains more than
words can express to describe the equality be-
tween women and men in Finland.
I understood, since the beginning, that leaders
in the OR are not the neurosurgeons with Pro-
fessor Hernesniemi but all the nurses. Nurses
have the true power. Professor Hernesniemi
many times says that “nobody is operating
alone“ and without nurses and anesthesiolo-
gists, no surgeon can operate. Nurses in the OR
have supported me very much. Without them
I couldn‘t have managed, especially in the be-
ginning. I‘m grateful to Saara for her daily sup-
port and encouragement. I will never forget my
first aneurysm surgery and the support of Sari,
the instrument nurse. All nurses are so profes-
sional and all visitors in the OR have noted
that. They are an example of how females are
leaders in Finland and how the society supports
them. Professor Hernesniemi says: “When you
fail in such a good working environment you
can blame only yourself“.
8.2.7. Conclusions
When I left Italy I also left a lot of problems
and negative aspects and some of them came
with me because they form a part of me and
my genes. Thanks to Finland I‘m improving.
Finland and the Finnish people have had a
healthy effect on me. They taught me to do my
job with method, they taught me to listen and
to speak less. They widened my horizons, they
taught me to see things from a different angle
and finally they made me understand that the
centre of the world can be anywhere and not
only in Rome.
After almost three years I can say that I love
Finland and Finnish people and I will make this
beautiful country and people known in Italy or
wherever I will decide to live. I will be forever
grateful to them for what I learned.

284
8.3. IMPRESSIONS OF HELSINKI:
ACCOUNT OF A VISIT – FELIX SCHOLTES
(LIÈGE, BELGIUM)
“Please, no neurosurgery“, he said, “just a per-
sonal account.“ That is what he asked for, the
Professor, as we respectfully call him. To most
of the local co-workers he is simply Juha. That
is also how he signs his emails before he has
even met you. This immediate friendly famili-
arity does not come as a surprise if you have
had the chance to see him in his department.
One immediately senses the serene atmosphere
in this microcosm lead by Professor Juha Her-
nesniemi.
Those who work here do exactly that: work,
with competence, attention and pride in a job
well done. No grumpy face, no raised voices, no
inconsideration. Everything happens with great
collegiality that expresses respect: respect for
each other, as well as for the challenging work
and its subjects, the patients. After a few weeks
in Finland, to me, this attitude seems repre-
sentative of a people that shines with humility,
calm, and helpful friendliness.
The Finns are well aware of life‘s essentials
and national history. Finland, which spans
across the polar circle, had been occupied for
a long time. The country became independent
less than a century ago, freed from Russian re-
gime by Lenin who had benefited from Finn-
ish hospitality until the coming of Red Octo-
ber. Initially, civil war broke out between the
socialist “Reds“ and the nationalist and capi-
talist “Whites“. The latter were lead by char-
ismatic C.G.E. Mannerheim and supported by
Germany, and aimed to establish a monarchy
at the time. After the defeat of the Reds, but
also the fall of the monarchy in Germany dur-
ing the First World War, the young nation was
finally built on a republican model. It was suc-
cessfully defended in a hard and bloody Winter
War against Russia in 1939/1940, lead again
by Mannerheim. Through a long, delicate act
of balance between the East and the West dur-
ing the Cold War, Finland has risen to become
one of the world‘s most respected democracies.
It was the setting for the 1975 Conference on
Security and Co-operation in Europe which
led to the Helsinki Agreement and thus to a
partial de-escalation of the Cold War. Now, it
finds itself consistently among the top coun-
tries in rankings of political stability, quality of
life, and wealth. Education is exceptional, with
Finland on the top of the three PISA rankings
of OECD countries.
Do not expect to understand a word of Finnish.
Due to its Finno-Ugric roots, it is as different
as Hungarian from the Germanic and Romanic
Languages most of us Europeans are used to.
Only sometimes one detects a certain etymo-
logical familiarity of one word or the other,
like soap (saippua, German: Seife), or trousers
(housut, German: Hose)… But, as soon as you
speak to the Finns, you will receive answers
in impeccable English, and so naturally that I
rapidly stopped apologising for my deficient
Finnish… The only person I met during the two
months who did not speak English was an eld-
erly lady selling plums and apples in the stands
of Hakaniemen Kauppahalli marketplace. By
the way, this is where you can find delicious
fresh vegetables and Finnish and other Scandi-
navian fish, the dill to go with it, even Limousin
beef, and cooking advice – in perfect English!
Nevertheless, my Portuguese colleague and
roommate Pedro and I both attempted to use
at least a few Finnish words. We never got
much further than kiitos (thank you) and hy-
8 | Visiting Helsinki Neurosurgery | Felix Scholtes

285
Figure 8-12. Marshall C.G. Mannerheim, the founder of the Töölö Hospital.
Felix Scholtes | Visiting Helsinki Neurosurgery | 8

286
Figure 8-13. The Olympic Stadium

287
vää huomenta (good morning), but even these
rather pitiable attempts brought us consider-
able sympathy from the waiter in the hospi-
tal cafeteria. With diligence and patience, she
guided us through the Finnish specialities that
were being served and instructed us on how to
combine them.
One eats well in Finland. The dark whole grain
bread is similar to what I know from my child-
hood in Germany. There is also the Swedish
knäckebröd. Sweden, during its time as a great
European power, had had its grip on the Finn-
ish territory. There is still a Swedish speaking
minority of about 5.5%, and Swedish acknowl-
edged as the official second language.
I was given the opportunity to come here for a
period of almost two months, as part of a year
abroad, after nine months in Montréal, Québec,
Canada, and a month in Phoenix, Arizona, USA.
As requested, I will refrain from using neuro-
surgical jargon, enumerating challenging cases,
and reiterating in detail what attracts so many
visitors and fellows to the University of Helsin-
ki Department of Neurosurgery. Nevertheless,
there are a few outstanding impressions that I
would like to share. First, there is the humility
of the experienced and lucid neurosurgeon that
Professor Hernesniemi is. He does not hesitate
even a second to share his critical appraisal
of his own operations and performance. And,
sometimes, the post-operative discussion is
longer than the clipping of a middle cerebral
artery bifurcation aneurysm. Professor Hernes-
niemi clearly appreciates the presence of the
visitors, fellows and colleagues, and willingly
shares technical nuances, personal surgical ex-
perience, approaches to decision making, sci-
entific facts, and the epidemiological peculiari-
ties of Finland, but also amusing anecdotes and
his critical views of the world.
No one speaks during operations except for
messages concerning the operation and the
patient. There is only Iskelmä Helsinki, a local
radio station. Iskelmä is an equivalent to the
German Schlager, or, as the Professor would
phrase it himself, “lousy music.“ When he op-
erates, the OR is filled with Finnish iskelmä
music or Finnish versions of international hit
songs from the past. “Lousy music allows good
surgery. It does not divert attention and gives
an appropriate background noise, that means
less stress for the co-workers than to ask for
complete silence.“ (J.H.)
Helsinki is a wonderful place to be. I arrived
in the beginning of September, at the end of
the summer, the days still warm and long. Here
the northern climate is moderate, thanks to the
Gulf Stream‘s influence on Northern Europe.
Thus, one does not realise that Helsinki, the
second most northern capital of the world, lies
at almost the same latitude as the southern tip
of Greenland and Anchorage in Alaska.
When taking strolls through the city, one is
taken by the spotless cleanliness and the spa-
ciousness of Helsinki, the abundance of parks
and green spaces, the impressive bedrock vis-
ible even between the city‘s buildings, with
even a church constructed within it! Some of
these small inner-city “hills“ provide refreshing
perspectives and views on architectural sights
like the Olympic stadium, the recently built
Opera House that overlooks the pretty bay of
Töölönlahti and its park, and Alvar Aalto‘s Fin-
landia convention centre. These urban patches
of nature provide space to breathe, to rest
among the trees or on a big stone, surrounded
by green grass, like right in front of my apart-
ment, situated at two minutes by foot from the
hospital and at walking distance from the city
center.

288
Besides parks and rock, water is omnipresent in
this city on the Southern Finnish coastline: ca-
nals, bridges, bays, basins, and small ports full
of boats. On the western seashore of the Töölö
district, close to the Sibelius monument, the
Helsinki inhabitants jog, walk the dog, and take
a cinnamon roll with a nice hot kahvi outside,
next to the sea, at charming Regatta Café. In
2002, the people of Finland, together with its
Norwegian neighbour, were the heaviest kahvi
consumers of the world, with approximately 10
kg per person, more than three times that of
the average Italian!
Lately, the weather is starting to change, and
nowadays it has been a bit colder but still sun-
ny. Mornings are becoming darker, days shorter.
Still, even now, as I am writing this in the mid-
dle of October, I tell myself what a perfect time
it is to be here. The warm yellow late afternoon
sun shines low on the beautiful-colored au-
tumn leaves, and on Töölönlahti with its typical
old Scandinavian wooden houses, and on the
Rinkeli ferris wheel towering high in the dis-
tance. The crepuscular purple light announces
the coming of dusk, and cyclists, joggers and
walkers head home.
Despite this abundance of nature, Helsinki feels
like a true capital, with a vibrant nightlife, shop-
ping centers and department stores like the re-
nowned Stockmann, museums, an impressive
number of high quality ravintolat (restaurants),
and obviously its architecture. The older build-
ings date mainly from Russian times. After their
victory over Sweden, the new occupants made
Helsinki the capital of the semi-autonomous
grand duchy, taking the role away from Turku
at the west coast in order to bring the govern-
ing senate closer to Russia. Helsinki had been
of strategic importance before, as witnessed
by the presence of the Unesco World Heritage
Sea Fortress Suomenlinna (or Sveaborg, as the
Swedish builders called it) that every serious
Helsinki-tourist should visit.
And admiring tourists we are, in addition to our
various professional missions, the visitors and
fellows at the Department of Neurosurgery.
Hugo, the neurosurgical resident from Ven-
ezuela, with a competitive international tennis
past; Paco, the heavy metal bass player from
Spain; Youssouff, the neurosurgery professor
from Senegal; Mei Sun, the experienced neu-
rosurgeon from China; Ahmed, from Egypt and
the friendliest neurosurgeon there is; Jouke, a
Dutchman with a passion for music; Rossana,
who we hope will finally share one of her Ital-
ian recipes with us...
Here, fertile grounds are laid for informal inter-
national exchange and the creation of bonds
across borders, some of which may last for
years and will have found their origin in a com-
mon visit to the Helsinki University Department
of Neurosurgery.

289

290
8.4. TWO YEARS OF FELLOWSHIP
AT THE DEPARTMENT OF
NEUROSURGERY IN HELSINKI –
REZA DASHTI (ISTANBUL, TURKEY)
I should start from May 2005 when I met Pro-
fessor Hernesniemi during national Turkish
Neurosurgical congress in Antalya. I was re-
ally impressed after listening to his lectures on
microneurosurgery of aneurysms and AVMs. At
the first possible moment I introduced myself
to professor and asked if I could apply for a
cerebrovascular fellowship with him. After ex-
changing a couple of e-mails he suggested me
to pay a short visit to his department in Hel-
sinki before getting accepted.
This short visit happened in the second half of
September 2005. We met at the hospital en-
trance in an early Monday morning and a long
working day started. My first impression from
the Department was a busy but very well organ-
ized neurosurgical center. I was warmly wel-
comed by every member of the staff. Beside the
Finnish colleagues there were also a group of
fellows and visitors from different parts of the
world. During that day Professor Hernesniemi
operated 6 cases in the same operating room.
From the first moment I was impressed by his
extraordinary surgical skill. I left the OR after
midnight and went to my hotel. The second
day was not different, however, operations fin-
ished earlier and and we managed to go for a
beer with other fellows. This was a good op-
portunity to get to know others and get some
useful information about the department and
the city. I left the place after a couple of hours
and started to walk in the direction supposed
to be towards my hotel in the city center. Af-
ter walking for almost one hour I came to un-
derstand that I went in a wrong direction and
ended up far from my destination. This was my
first good memory with the Finnish beer.
At the end of the week I was accepted for one
year fellowship. The reference from Dr Ayşe
Karataş (his former fellow from Turkey) was
important in this decision. I was very excited
and motivated as this was the unique oppor-
tunity to work with the one of the best cer-
ebrovascular surgeons in the world. However
I had to arrange and organize everything very
well. I planned to move to Helsinki with my
family as their support would make everything
much easier for me. Being accepted in the so-
ciety and school in a foreign country, however,
could have been difficult both for my wife and
my daughter (Nakisa was almost 8 at that
time). I arranged all the necessary permissions
from both universities, closed my apartment
in Istanbul, sold my car and in the evening of
November 8th, 2005 we were in Helsinki. We
moved to a flat close to the hospital. With the
great help of Professor Hernesniemi we man-
aged to find a place in one of the oldest and
best schools in the city (Ressu) for my daugh-
ter.
I started to work immediately the next day,
Dr. Reza Dashti
8 | Visiting Helsinki Neurosurgery | Reza Dashti

291
while my wife was taking care of all aspects
of our life other than neurosurgery. In the con-
trary to our worries it took a very short time
for all of us to feel at home in this new envi-
ronment. This was because of great support we
received from all the members of staff in the
department.
Working with a mentor like Professor
Hernesniemi was a unique experience. From
the first moment it was possible to see how he
is committed to his fellows and visitors. It was
not only possible to observe the technical as-
pects of cerebrovascular surgery at the highest
level of excellence but much more. Among his
first teachings was the principle of being first a
good human, then a good medical doctor, and
finally a good neurosurgeon. The compassion
and caring that he has for his patients is one of
his most admirable qualities.
My fellowship period was later extended to
two years. During this period I had the oppor-
tunity to assist professor during 807 microneu-
rosurgical operations. Starting from the first
operation it was possible to note how every
step is clean, fast and going smoothly. To see
how every member of the team was acting so
professionally was very exciting. The operating
room was clean and calm with no noise or un-
necessary talking. Professor Hernesniemi was
rarely asking for instruments as the scrub nurse
was following every step from the monitor. This
was true for the anesthesiologist and any other
member of the team as well. As every proce-
dure was done very fast and through small,
tiny corridors in the surgical field, it was rather
difficult to understand anatomic details in the
first weeks. I can say it took me a month to
understand where M1 is. To learn how it is pos-
sible to perform the whole operation with two
classical instruments (suction and bipolar for-
ceps) and may be two additional ones, to use
no retractors except for cottonoids, effective
use of sharp dissection, expansion of subarach-
noid spaces with irrigation (water dissection
technique) and many other details was really
impressive. Apart from daily rounds we spent a
good deal of time to discuss every single case
before, during and after surgery. Analyzing op-
erative videos was another important part of
my training. This was a unique experience to
be able to watch many hundred videos as many
times as needed and then to discuss them with
Professor and other fellows. The aim was to
catch surgical tricks and to learn to “operate on
each case in your mind“. X-ray meetings every
morning and cerebrovascular meetings every
week were a good opportunity to go through
all the cases once more. Starting from the first
day I had enormous support from all the mem-
bers of the nursing staff and anesthesiology
team in the OR. This was not different in other
parts of the department. Soon I started to feel
at home by all means.
A fellowship is a unique opportunity to share
similar interests, ideals, or experiences. It is al-
ways interesting to meet people from different
cultures and backgrounds. This gives you the
chance to improve yourself both intellectually
and personally. Meeting a high number of visi-
tors and fellows from all over the world and ex-
changing experiences has been another part of
my training. Similarly, I have learned a lot from
each member of the Neurosurgery Department
at Töölö hospital.
During my stay I had the opportunity to get to
know many outstanding persons in the field of
neurosurgery. I remember that in the first
month of my stay Professor Konovalov and
a group of experienced neurosurgeons from
Moscow visited the department. I found myself
in the front line, taking care of these important
visitors. After watching a couple of cases oper-
ated by Juha, Professor Konovalov asked me to
show him some operative videos. I went to the
videotape archive and selected some videos.
Then we proceeded to watch the videos on the
big screen in the lobby of the OR. The videos
showed some difficult cases that you maybe
would not like to show to such an important
neurosurgeon as Professor Konovalov. I felt
Reza Dashti | Visiting Helsinki Neurosurgery | 8

292
that Juha was standing in the corner, watching
us, and may be wondering what I was trying
to do to his career. I stopped the videos. The
result was a sudden change to a video from
some television channel with images that one
would not immediately associate with high-
level neurosurgery but rather with some “late
nite action“ of a very different kind. “This is
from Reza‘s private collection!!“, Juha quipped,
just before I fainted and fell flat to the floor.
The visit of Professor Ausman was a turning
point in my fellowship. In the second day of
his stay he suggested Juha to publish his surgi-
cal experience. I was lucky to be in the right
place at the right moment. This was the start of
the series of publications in Surgical Neurology
on microneurosurgical management of intrac-
ranial aneurysms. This project - still running -
became the most important part of my training
as a cerebrovascular fellow. Apart from reading
and studying all the papers on anatomy and
surgical techniques for every aneurysm site,
I watched nearly 500 videos and interviewed
Professor Hernesniemi about his surgical tech-
niques based on 30 years experience on aneu-
rysms surgery. I am very thankful to Professor
Juha Jääskeläinen who trained me how to pre-
pare and write the papers. I had also enormous
support from Professor Niemelä, Dr. Lehecka
and Dr. Lehto, both as friends and co-workers.
Mr. Kärpijoki was my teacher in the technical
and audio-visual part of the work. The Helsinki
AVM database was another important project
which I took part. I worked closely with Dr.
Laakso and Dr. Väärt on this project. I had the
opportunity to check the images of more than
400 cerebral AVMs which was a great train-
ing. The result is a “never to be repeated“ AVM
database. Until now I have been involved in
38 published articles from the Department of
Neurosurgery in Helsinki. Although I am still
collaborating with the projects this extraordi-
nary number of papers has been and will be
very important in my career.
My involvement in The Helsinki Live Surgery
Courses was an exceptional achievement. With
the concept of open-door surgery I have had
the opportunity to see the surgical techniques
and experience of many world known neuro-
surgeons. Another important activity was the
LINNC course. This happened during the visit
of Professor Jaques Moret. All of a sudden we
found ourselves involved in a live transmission
of surgery from Helsinki to Paris for an audi-
ence of close to 1000 people. This has been a
unique experience for me. I was responsible for
commenting on the surgeries with my ear set
connected to the control center in Paris and
satellite people and broadcasting staff in Hel-
sinki and many others. During transmission of
the first case I was extremely excited (as usual)
and also very nervous about my ugly voice. Af-
ter knowing that my voice is tolerable and not
killing people I was happy.
Working with a hard working person such as
professor Hernesniemi was not easy, as he is
not the most flexible man in the world. Tasks
should be done fast and perfect like his sur-
gery. Days were always long and the weeks
were usually starting at Sunday afternoon.
The load of projects and operations plus many
other tasks was heavy but not intolerable. Dur-
ing this period we had some difficult moments
every now and then, but always managed to
overcome.
After spending a splendid two years in Helsinki
I returned back to my department in Istanbul.
At the beginning adaptation to my old environ-
ment was not so easy. I started to miss all my
good friends in Helsinki from the first moment.
I realized that Finland became my third home
country. Leaving Finland was much more dif-
ficult for my family than me. They were happy
and comfortable in Helsinki. After going back
we had to establish everything from the be-
ginning. Especially my daughter had to get
adapted back to her old school. This took some
time but we could manage. I started to change
my surgical habits according to what I have
learned in Helsinki. At the beginning it was not
8 | Visiting Helsinki Neurosurgery | Reza Dashti

293
so easy but the final result is good. I got enor-
mous support from Professor Kaynar and I am
now involved actively in vascular cases in my
department. Now, I feel more skilled and confi-
dent in providing care for my patients.
My experience with professor Hernesniemi had
great impact on my professional and personal
life. This has been a turning point in my life.
For me, Juha has been a teacher, a hero, a close
friend and someone very special. I am proud of
being a member of the Helsinki Neurosurgery
team.
Reza Dashti | Visiting Helsinki Neurosurgery | 8

294
8.5. MY MEMORIAL OF „GO GO SURGERY“ IN
HELSINKI - KEISUKE ISHII (OITA, JAPAN)
I was fortunate to be selected for a course of
continuing professional education at the De-
partment of Neurosurgery at the University
of Helsinki. Here, I report my memories of the
training period in Helsinki from March 2003 to
June 2004, and describe how the training has
made differences in my current attitude to my
practice as a neurosurgeon.
I started my residency in neurosurgery in 1993
and became board certified by the Japan Neu-
rosurgical Society in 2001. It had been my sin-
cere hope since then to have an opportunity
to study in an institution abroad to see a wide
variety of surgical cases. My dream became
true when Professor Hidenori Kobayashi, the
Chairman of the Department of Neurosurgery
at the University of Oita, introduced me to Pro-
fessor Juha Hernesniemi. The both professors
were trained under Professors Drake and Peer-
less, and have been long-lasting close friends.
8.5.1. The first impression of Finns
Men in Finland seem rather quiet, whereas
women are cheerful and speak a lot, as if Finn-
ish ladies actually have acquired special skills
to keep talking even when inhaling. Because of
their talkativeness, I felt that women seemed
to take the initiative on many aspects. Overall
standards in culture, education and economy
are superb in Finland. Finland is one of the
highest-ranked welfare states in the world, and
public security and order is highly maintained
throughout the country. Finns are hard work-
ers and very industrious. I was surprised to find
out how many resemblances there are between
Finns and Japanese regarding the behavior and
daily habits. As a few stereotypical examples,
the Finns and the Japanese are both rather shy
and get easily blushed (which is actually more
obvious in Finns due to their pale skin tone);
a salute with slight nods is a common gesture
for both Finns and Japanese; and we both take
our shoes off inside our homes. On the other
hand, everyone calls each other by their first
name as if they were close friends - even the
professor - which was one of my biggest sur-
prises.
8.5.2. The Helsinki University Central Hospital
The organization of the hospital utilizes one
of the most advanced information technol-
ogy and people‘s responsibilities were highly
specialized, allowing each worker to use their
time at work very effectively. Effective use of
time at work also meant more time personal
free time and longer vacations, which was ex-
tremely impressive for me. This is an example
of a difference in national characteristics and
social structure that struck me during my stay
in Finland.
8.5.3. Professor Hernesniemi and
his surgical techniques
Highly effective, but comfortable OR was em-
bodied in front of me. Beautiful team work
among neurosurgeons, neuroanesthesiolo-
gists and nurses support excellent patient care
also during pre- and postoperative periods.
Dr. Hernesniemi was appointed as a Professor
at the University of Helsinki in 1997, and has
since been in charge of the most surgically-
challenging cases of cerebrovascular disor-
ders and skull base tumors. Prof. Hernesniemi
performs also the positioning and craniotomy
himself, as he believes that these are one of the
most critical steps of neurosurgery and work
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295
as a good warm-up for the microsurgical part
of the operation. One can only admire Prof.
Hernesniemi operating more than 500 major
cases a year, day and night. His performance
in the OR put me in an “operation shock“ and
totally changed my understanding of microsur-
gery, which to me before I saw him operating
was just fingertip movements under the micro-
scope in sheer tranquility. In a room with radio
music on, Prof. Hernesniemi freely positioned
himself around the microscope with a mouth
switch. Every procedure was undertaken in a
standing position with very little time without
movement. It was like space walk. I, viewing
his performance through assistant‘s eyepieces,
was also put under the highest pressure I have
ever experienced, and was oftentimes forced to
take an almost impossible posture, all of which
exhausted me mentally and physically. He also
performs his surgery in extremely short time. I
remember him joking that short operation time
is always welcomed and appreciated by the
staff but not necessarily by patients and their
family members. Of course, fast and profes-
sional teamwork by neuroanesthesiologists and
nurses greatly contributes to Prof. Hernesnie-
mi‘s operational performance. The team also
quickly accustomed to me, who was in a to-
tally unfamiliar situation and not performing
very well initially. Within three months, an
unspoken sense of mutual understanding was
established between me and the staff, and the
scrub nurses never since missed to pass me
the instrument I needed during the operation
without naming it. My main responsibility was
to perform the closure of the wound, which I
did completely under the microscope, partly for
training purposes.
Prof. Hernesniemi‘s consistency in the attitude
and eagerness to incorporate any tips that
might be beneficial to improve his operational
performance was really impressive to me. It is
not easy to keep up with his spirit in learning
from discussion with visitors from around the
world and to reflect the assessment to one‘s
own operational techniques. He is constantly
interested in advancing any aspects of the sur-
gical techniques as well as the institutional
performance in the neurosurgical arena.
I recall my days of fellowship, when he of-
tentimes questioned himself would the time
he focused on improving his operational skills,
but occasionally missed being with his fam-
ily, be worthy; or how should his life be as a
neurosurgeon, or even as himself? These ques-
tions taught me dedication and spirit of never
giving up, which is supported by the passion
to go after a certain thing, neurosurgery. Prof.
Hernesniemi, and his team who undertake
many difficult cases days and nights, showed
me that the important thing is an aim, not
means.
8.5.4. My current days in Japan
Since my return to Japan, I have been practic-
ing as a neurosurgeon, with a memorial photo
with Prof. Hernesniemi on my desk, to keep
up with the best spirit I was given during my
training in Helsinki. Of particular note, I have
extended my medical commitment to extra-
hospital activities as part of the life-saving
team. I believe that this is one way to further
project my experiences in Finland to our daily
practice. Together with paramedics in doctor‘s
car and helicopter, outreaching to patients in
jeopardy and accomplishing early intervention
indeed have helped successful rescue and sub-
sequent treatment.
8.5.5. To conclude
During my stay in Finland, many people sup-
ported me. I thank all of them, not only Prof.
Hernesniemi, but also faculty physicians, nurs-
es, paramedics and other staff, in my second
country, Finland. I, the “Last Samurai“ as my
dear friend Finns called me there, will main-
tain my effort to develop my skills and sprits
as a neurosurgeon. I would also like to send my
best wishes to members of the Department of
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296
Neurosurgery at the University of Helsinki for
further medical and scientific advances.
8.6. AFTER A ONE-YEAR FELLOWSHIP –
ONDREJ NAVRATIL (BRNO, CZECH REPUBLIC)
Comprehensive descriptions of details regard-
ing the cerebrovascular fellowship with Profes-
sor Juha Hernesniemi have been provided by
other fellows. But how the fellowship influenc-
es surgical habits of a neurosurgeon? Learning
from someone else‘s experience, successes and
failures, substantially facilitates the profes-
sional growth of a neurosurgeon. That is why
we all came to Helsinki. I was highly motivated
to come to Finland because I wanted to have
some advantage over other colleagues at my
department. I felt that working at another de-
partment in a different country might help me
to meet this expectation and enrich me a lot.
When deciding to come to Helsinki, I completed
the sixth year of my residency programme and
started to learn the principles of more complex
operations. This should probably be the earliest
time for a neurosurgeon to come to Helsinki.
To have some practical knowledge in cere-
brovascular neurosurgery might be even bet-
ter because you can continue to build on your
personal experience. The upper age limit is not
important because the improvement of neuro-
surgeons´ skills is a lifelong task. However, the
older one gets, the more complicated the situ-
ation becomes to leave home for a longer pe-
riod. Due to my one-year stay in Australia dur-
ing medical studies, my English knowledge was
good enough for the fellowship. Although the
Australian stay was not related to neurosurgery
and medicine, I knew that it has opened an-
other dimension of perceiving the world and I
expected similar things from Finland in relation
mainly to neurosurgery. And how the expecta-
tions were fulfilled?
At the end of the fellowship, many worries and
doubts came to me, combined with tiredness
that naturally appears when one pushes him-
self to his best performance. After one year
away from my home country and gaining so
much inspiring insight into the highest level
of neurosurgery, one begins to worry. Will I be
able to use some of Juha Hernesniemis‘ tricks?
And if yes, will I be able to perform them in such
an excellent way? How should I behave to my
environment to make them accept my different
requirements in the OR? Is it possible to apply
different attitude to operative techniques else-
where? Will I be able to change the habits at my
home department? Gradually when time passes,
I will have answers to these questions. Simi-
lar worries will probably come to every fellow
before they return home. However, the condi-
tions and positions of the fellows in their home
countries differ, thus resulting in different pos-
sibilities to put into use what one has learned.
Furthermore, after the big change of the entire
environment, after having got used to the way
things are, another change, even bigger this
time, comes again – the return back home.
After coming to my home country, the Czech
Republic, I took three weeks of holiday. I con-
sidered it very important to get to full strength,
clear my mind and to settle down at home. Dur-
ing these weeks I was thinking over and over of
coming back to my neurosurgical department
and visited my family and friends after a long
delay caused by the fellowship. I believe that
strong support from family and friends in neu-
rosurgery has a paramount importance and
helps one to be strong at work.
Considering the neurosurgery itself, my atti-
tude has already substantially changed in Hel-
sinki but only in my mind. After spending all
the time in operating rooms, watching and as-
sisting at 424 high-level operations performed
by Juha Hernesniemi from 2007 to 2008, one
learns to recognise superb microsurgery and
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297
teamwork. It is not a gift or natural ability, but
an extremely hard work and dedication every
day, what makes one real professional and
giant. The spirit and power of Helsinki Neu-
rosurgery has already motivated hundreds of
neurosurgeons all over the world.
Currently I work at Department of Neurosur-
gery in Brno, Czech Republic, which is a me-
dium-sized department. Given our catchment
area, we do not get as many cases as Helsinki
Neurosurgery. One can have only few opera-
tions in a week. Therefore “Juha Hernesniemi‘s
rule“ - you can learn something new from eve-
ry case – is even truer, and similar cases fol-
low each other much more infrequently than
in Helsinki. After the fellowship, I immediately
incorporated some of the things learned into
my routine, and I feel that my technique has
improved a lot. For an interested reader, some
examples of the things I use from Helsinki are
given below.
Like in Helsinki, before the operation I try to
find my own way of operating the case, begin-
ning with a thorough studying of the images.
When unsure of how to operate, watching
operative videos and the imagination of Prof.
Hernesniemi in the same situation the night
before usually helps to find an optimal way.
Now I believe much stronger that my mind is
somehow getting ready for the stress of opera-
tion and the performance is much better when
coming to the OR with the mental image of
the intended operative course. Trying to “oper-
ate in one‘s own mind“ is one of the key points
leading to success in surgery. When you oper-
ate in your mind, it is like you would have done
the operation already. From the former fellows‘
and observers‘ point of view, I can confirm that
this works also in practise. When I was in Hel-
sinki, taking the pictures and downloading the
videos belonged to my everyday tasks. Later
on, archiving the videos paid back. Apart from
studying the anatomy and literature, watching
unedited videos keeps the operations – tech-
nique, principles and strategy, seen in Helsinki,
alive. This practically prepares me to be able
to operate and have impact on the course and
the duration of an operation. It is time-con-
suming, but very effective in the end. Precise
positioning and simultaneous imagination of
intracranial structures has proven even to me
to be extremely important as every small detail
plays its role in the end. One or two millimetres
may not be significant elsewhere, but they are
extremely important in neurosurgery and may
play a significant role in succeeding or failing
during surgery. Polite and calm behaviour is a
must. When you get along well with people at
work, they help you when fighting in a difficult
situation at work. In my opinion, the principles
of thoughtful work are applicable not only in
medicine but in every profession. Until now,
this tactics and behaviour has already paid back
many times. I will never forget my first case of
ACoA aneurysm with frontal hematoma. Natu-
rally I was worried, but despite late night and
tiredness, angry swollen brain and intraopera-
tive aneurysm rupture I managed the operation
with the help of a scrub nurse. In conclusion,
without the Helsinki fellowship, definitely, I
would have not performed in such a way.
However, nurses and colleagues were not co-
operating fully when I was implementing
changes in technique and operative tools. I
have faced many times unpleasant questions
and behaviour. These facts are based on natu-
ral rivalry and behaviour. Therefore we have
to get used to fight against them and manage
them in a daily routine. For example: bipolar
forceps switched on and off by a scrub nurse,
the use of syringe and needle for water dissec-
tion, operating trauma cases and closing the
wound under the magnification of microscope,
are some of the things I introduced based on
Helsinki experience. The first few weeks were
very difficult because everybody was watching
me and I could feel that they were thinking I
was crazy. Nowadays, after full concentration
and not failing during one and half year after
the fellowship, it is much easier and the staff
around knows what they can expect from me
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298
in the OR and that I never behave to them in-
adequately. The appropriate appreciation of
their work is humble and motivating support
for their further work.
Not only innovative surgical techniques make
Helsinki Neurosurgery so famous. During my
stay in Helsinki I understood the importance
and context of working on publications. High
publication and studying activity, producing
high-level articles in the field are excellent.
Furthermore they help to spread local experi-
ence all over the world to neurosurgeons that
cannot come to Helsinki for various reasons.
The papers dealing with microsurgical tech-
niques and from experimental neurosurgery
are of superb quality and worth of reading and
remembering. The cooperation with neurosur-
geons and fellows in Helsinki – Martin Lehečka,
Mika Niemelä, Reza Dashti, Riku Kivisaari, Aki
Laakso, Hanna Lehto and others was smooth
and inspiring. I have learned a lot from them
and this also helps me at home when prepar-
ing papers and presentations. Their permanent
ambition to develop their neurosurgical and
scientific skills remains a strong motivation
for me. Working on projects at Helsinki Neu-
rosurgery helps one to feel as being home, you
feel involved and you can participate depend-
ing on your ability, will and desire to publish.
Then you can benefit from being an author or
co-author and this helps when building your
position back home. Based on Finnish experi-
ence, we have also launched our own aneurysm
database in Brno.
Retrospectively seen and despite all difficult
times, the enormous effort to manage one year,
the time spent in Helsinki was very fruitful, ef-
ficient and beneficial to be done by somebody
who wants to learn neurosurgery to be per-
formed at its best. One year in Helsinki Neuro-
surgery influences your life positively and helps
your further development enormously. Based
on my expectations, I can say that Helsinki stay
has fulfilled a discovery of another dimension
of neurosurgery in my mind, but also another
dimension of honest but demanding human
cooperation on the highest level. Personally for
me, it has opened my way to the majority of
vascular cases at my department. This privilege
is a great step for my further improvement in
the field.
When coming back to his or her home coun-
try, the fellow should definitely concentrate to
his or her work. To be able to use what he or
she has learned during the fellowship, every ef-
fort should be used to change the conditions
for this purpose. First year after coming back is
the most difficult, because changing the hab-
its takes a lot of time and energy. The fellow
should always continue the same way as dur-
ing the fellowship, use “the Helsinki fast pace“
at work (i.e. very high assignment) and be able
to further develop his or her skills based on the
experience gained.
I will always look forward to coming back to
Helsinki to see another, not only cerebrovas-
cular case. Maybe I can notice some details
that I may not have noticed before, or a new
technical trick. The spirit of Helsinki will always
remain huge and strong in my soul and I hope
that it will continue to guide my neurosurgical
career in the future.
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8.7. ONE-YEAR FELLOWSHIP AT THE
DEPARTMENT OF NEUROSURGERY
IN HELSINKI – ÖZGÜR ÇELIK
(ANKARA, TURKEY)
2007 was the last year of my residency in neu-
rosurgery at Hacettepe University Hospital in
Ankara. At that period I was being encouraged
to apply for a fellowship, especially by my fa-
ther and mother who are also medical doctors.
After deciding to apply for a fellowship, it was
time to find the right institution. Professor
Hernesniemi and Helsinki Neurosurgery were
at the top of my list since I had been interested
mainly in neurovascular surgery during my resi-
dency. As a young and inexperienced neurosur-
geon, it was a dream for me to be accepted to
such a famous center as a clinical fellow. One
of those days Professor Uğur Türe phoned and
told me to send my CV and an e-mail to Pro-
fessor Hernesniemi to apply for a fellowship.
I sent the e-mail and received the reply in 10
minutes. I was invited to Helsinki for one week
to discuss the situation. I immediately com-
pleted arrangements and went to Helsinki. I
was warmly welcomed by every member of the
staff and also a group of visitors from different
parts of the world. During this one-week visit
I had the opportunity to observe his extraordi-
nary surgical skills and performance. I was re-
ally impressed by him, as well as his team and
at the end of this short visit, I was accepted
to be a part of that team as a clinical fellow
for one year. The reference from Prof. Türe was
important in this acceptance. My fellowship in
this legendary center began immediately after
my graduation from neurosurgical residency. I
worked there as a clinical fellow for one year
from November 2007 to November 2008. The
most important concern for me before going to
Helsinki was long, dark and cold winter, since
unusual weather conditions in winter had been
emphasized to me seriously several times. For-
tunately, Prof. Hernesniemi found a perfect
solution to keep me and other fellows (Ondra
and Rossana) away from depression. We really
could not find time to face this problem due
to intensive program. Prof. Hernesniemi was
the most hardworking person I have ever seen.
Although it was fun, keeping up with him was
taking all our time and sucking our energy. I as-
sisted Prof. Hernesniemi during 452 microneu-
rosurgical operations. However, the number of
his operations watched by me was even more
than a thousand since he has an open library
of operation videos for visitors and fellows. The
fellows were also responsible for taking care of
these records and video editing to make them
ready for presentations and scientific projects.
Watching these videos and discussing about
them with Prof. Hernesniemi was one of the
most beneficial part of my training. Another
important task for fellows was taking care of
visitors from different parts of the world. Dur-
ing my stay, due to high flow of visitors, I met
a high number of neurosurgeons from differ-
ent countries. This provided me a good chance
to share experience and learn from each other.
This was also a good opportunity to have many
friends and connections in the international
neurosurgical society. Besides these activities,
fellows were also working on different projects.
I have been involved in 10 published articles
from the Department of Neurosurgery in Hel-
sinki so far. Certainly, our lasting and future col-
laboration on other projects as well as published
articles will be very important for my career.
When I started my fellowship and began to as-
sist him during the operations, I had the feeling
that these operations cannot be done better.
After a couple of weeks I realized my mistake,
because these operations were being done bet-
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301
ter everytime by him. Despite his incredible sur-
gical skills and established main surgical prin-
ciples, I noticed his struggle to push himself to
do better and better. He was always trying to
improve himself as well as people around him. I
think it is a kind of challenge and a way to en-
joy life and neurosurgery for him. My other ini-
tial wrong observation was about his surgical
speed. In the beginning of my fellowship, my
(like other people‘s) strongest impression about
his operations was how fast he completed the
surgical procedures. In the subsequent period,
I realized that Professor Hernesniemi is not a
fast neurosurgeon. Although, generally, pa-
tients spend no longer than one hour in his OR
for treatment of their neurosurgical disorders,
the actual time of surgery for Professor Her-
nesniemi is not that short. He starts to operate
on a case immediately after he is consulted for
neurosurgical pathology. He sits down in front
of the radiological workstation to study the im-
ages and starts to operate in his mind. He sim-
ulates every small detail with his inner vision
(patient position, surgical strategy, incision,
location, expected surgical difficulties). He pre-
pares himself for surgery and avoids everything
that interrupts his concentration or influences
his surgery negatively. He always performs the
surgery a couple of times in his mind before
going into the OR. The final, short but impres-
sive step which takes place in the OR is the re-
sult of this rather long and heavy mental work.
Finally, I want to come to the most important
point I learnt from Hernesniemi School. Man-
agement of neurosurgical patients? Decision
making? Surgical technique? Surgical tricks?
Fundementals of microneurosurgery? Certainly
I learnt many things about the issues men-
tioned above. However, the most important
things I learnt from him are beyond advanced
surgical knowledge (although they are unique).
I think Professor Hernesniemi is a teacher of
not only neurosurgery but also life. How should
a neurosurgeon work? How should the one
train? How should one learn and teach? How
should one behave? How should one present
himself to patients, to collegues and to friends?
Briefly, how should one be a good human being
and a good neurosurgeon? I believe that these
are the things that cannot be learnt elsewhere.
I really feel very honored and privileged to have
a master, a mentor and a friend like Professor
Juha Hernesniemi.
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8.8. SIX MONTH FELLOWSHIP – MANSOOR
FOROUGHI (CARDIFF, UNITED KINGDOM)
8.8.1 How it began
As a member of the Rainbow team, it has been
a privilege to be in the Neurosurgery OR‘s of
Helsinki in Finland between January 2009 and
July 2009. We were welcomed here with the
characteristic open arms from the chairman of
the department, Professor Juha Hernesniemi.
We truly experienced the hallmark concept of
the Rainbow team, which is inviting and em-
bracing men and women from all races, nation-
alities, cultures and creeds, thus exemplifying
unity in diversity. The senior members of the
surgical staff including the Associate Professor
Mika Niemelä, vascular fellow Martin Lehecka,
the wonderful team of anesthesiologists, nurs-
ing staff and residents deserve a special men-
tion.
It was during the European Association of
Neurological Surgeons meeting in Thessaloniki
2004 that I was introduced to the Hernesniemi
concept of microneurosurgery through his talks
and thought provoking presentations. Many
were stunned regarding the alleged quality and
quantity of vascular neurosurgery cases. There
were many audible sighs of disbelief, amaze-
ment, approval and disapproval, with mixed
feelings all too often found in neurosurgery
gatherings. Could this be true? MCA aneurysm
clipping regularly done in less than 30 minutes,
basilar aneurysm clipping in 1 hour! We were
asked to see for ourselves this safe, fast, and
simple surgery. It was stressed that fast did not
mean “hurry“, rather smooth, rehearsed and ef-
ficient. Those few senior surgeons that had vis-
ited and seen Juha were more quiet, attentive
and respectful.
The advent of coiling for aneurysms seemed to
be the beginning of the end for the vast major-
ity of vascular microneurosurgery in my home
country. We are assured that this will evolve
with further technologies including pipeline
stents, maybe some form of nanotechnology,
then maybe simple pills. Hopefully some day
simple prevention rather than treatment will
be the main focus. However, it was clear that
for the foreseeable future there are going to
be more instances where even more skilled and
advanced exosurgery was required to deal with
what others could not do and on balance needs
to be done! Some have to keep it alive and
at the highest and greatest standards. Could
these claims be true? In a non-private govern-
ment funded health system? Simple, fast and
safe excellent microneurosurgery?
If justice is to be served then there was only
one thing to do, and a principle of justice rang
in my head “see with thine own eyes and not
through the eyes of others, and shalt know of
thine own knowledge and not through the
knowledge of thy neighbor.“ So I paid the fee
for the next Live Course and went to see for
myself.
There was another major influencing factor and
that was the character of Juha. His kind man-
nerism and humility was so clear and evident
and attractive. It is said that “A kindly tongue
is the lodestone of human heart!“ Many train-
ees from a variety of nationalities and back-
grounds with wide ranging levels of experience
use to show off Juha‘s personal card presented
to them by him. All questions and communica-
tions addressed to him were answered by him
personally, promptly with warmth and kind-
ness. This was wonderful and could only fuel
my curiosity.
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It was then that following the effort of traveling
and witnessing during the earlier experience of
the Live Course that many of us became aware
of the exemplary standards of microneurosur-
gery in Helsinki. The safe, fast, efficient, simple,
consistent and effective techniques we wit-
nessed changed our way of thinking and in-
stilled great confidence in exosurgery for spe-
cific simple or complex problems. Fast did not
in any way suggest hurry, but instead meant
efficient use of time, avoiding unnecessary
hold ups and delays, utilizing knowledge of
anatomy and painfully practiced and rehearsed
microsurgical skills. These were presented with
beautiful fluency of movement and obvious ex-
perience.
The exemplary organization of dedicated staff,
uncompromising use of best equipment, avail-
ability of tools increasing the surgical arma-
mentarium, combined with consistency made
sure operations and treatments happened ef-
fectively, swiftly and minimizing neurological
distress and risks. Such distress maybe in the
form of decreased cerebral blood flow during
temporary clipping minimized by fast and flow-
ing surgery, and risks such as infection miti-
gated by meticulous technique and short op-
erating times. The more astonishing thing was
to witness such great setup of neurosurgery in
a relatively small country governed by social-
ism, ensuring no private or financial incentive,
limited population base and far less than ideal
geography catered for by 4 other neurosurgical
centres.
8.8.2. The place and the people
Even though the leadership and microsurgical
standards evident in Helsinki are decisive fac-
tors for such great reputation, the people and
general culture of Finland are key elements and
deserve a special mention. Being in Finland is
a wonderful and an unforgettable experience.
If you like contrast between winter and sum-
mer then you are in for a treat. In the land of
the thousand lakes the cold winter nights are
dark and long and the pleasant summer days
are long and bright. You can walk on the sea in
the winter, enjoy tranquil and peaceful walks
or treks, and celebrate and welcome the arrival
of long summer days in style. A short inexpen-
sive boat ride around 1.5 hours or helicopter
trip little over 15 minutes takes you to Tallin,
the capital of Estonia, where you can enjoy this
beautiful city with its medieval passages and
picturesque cathedrals and castle. A short trip
by plane or via a comfortable train ride can
take you north through the beautiful country
side to Lapland, the home of the original Father
Christmas, and in the cold months to see the
northern lights.
On my arrival I was amazed to see such clean,
organized, efficient and technologically ad-
vanced system of transport and infrastructure.
A talkative and philosophical bus driver from
Helsinki airport told me on my first day here,
that the Finnish have traditionally worked hard
in the summer to survive the winter. There is no
leaving till tomorrow what you can do today.
This is combined with a great sense of solidar-
ity, equality and basic right. Helsinki is probably
the calmest, cleanest and the safest capital city
in the world. The city of Helsinki and surround-
ing districts has a population of just over 1
million inhabitants. A visitor, during short and
pleasant walks in one or two days, can explore
its distinctive landmarks, such as the harbour,
cathedral, parliament buildings, museum of
modern arts, opera house, Mannerheimintie
street and Stockmann department store, and
a personal favourite, the underground Temp-
peliaukio church and its brilliant acoustics. In
Helsinki the standard of commerce, education
and technology is high and the city contains
eight universities and six technology parks.
In the hospital many fellows and visitors have
become used to leaving their belongings in-
cluding laptops and etc. in the visitors room
or conference room while watching operations,
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304
going to eat or out of the department. We have
never even heard of any crime in the vicinity of
the hospital. The courtesy, polite behaviour and
good citizenship is probably best evident when
observing parents and their children in pub-
lic places, whether in shops, parks, clinics or
public transport. There is extremely seldom any
shouting or otherwise raising of voices. Despite
many outings locally I have never witnessed
any form of violence, graffiti, or very rude be-
haviour. This public seems to be bereft of anger,
malice or envy.
With the high price of goods and services the
only danger for visitors seems to be boredom
but only for those who enjoy things licentious,
generally illegal or very harmful. The only price
you pay for being here is the relatively high
price of everything. This reflects the general
wealth, taxation and hard work of a largely
socialist society. It insists on the provision of
the highest level of education, excellent trans-
port systems and social welfare. The high level
of education has resulted in one of the most
productive societies in the world. The notice-
able characteristic of the people is their level
of education and awareness of the rest of the
world. The pleasant Finnish courtesy, calm and
quite mannerism and lack of impulsive behav-
iour and commotion are so very obvious and
pleasant. This is especially so for any Latino
or warm blooded visitor. The lack of the warm
verbal and even occasional tactile expressions
is only a perception to any visitor and far from
reality. This becomes clear if you smile first, en-
gage and start a friendly conversation.
8.8.3. The Rainbow team and its Chairman
Just like the many colours of the rainbow, there
are many colours, races, creeds, languages and
cultures that have been and are working with,
learning from and spreading the concept of
microneurosurgery and standards of Helsinki
neurosurgery and Prof. Hernesniemi. To under-
stand this you only have to see the map of the
world in the OR lobby, and the number of pins
placed by the respective visitors in the various
territories and countries that they have jour-
neyed from. It is understandable to see why
many want to come back and stay to learn
more, contribute to and be a part of the team.
Like different coloured flowers in a garden each
brings its attributes. Being part of the rainbow
team we realise that “The Earth is but one
country and mankind it‘s citizens!“
It is not easy to perform more than 11,000
microsurgical cases, over 500 AVM opera-
tions and more than 4000 aneurysm surgeries.
These figures are unparalleled, especially when
you consider that the cases are not prepared
for Juha, so that he will arrive and do the last
touch dissections or place the aneurysm clip.
It is from the positioning until the job is done!
This is why so many visitors continue to come
here to see the whole performance. Neurosur-
gery for the chairman and team in Helsinki was
clearly never just a job, but a passion. Nurtur-
ing talent, courage to change, tact and wis-
dom to engage and influence, vision to lead,
patience and perseverance to see hard work
come to fruition, and great love and humanity
for all is what we aspire to and what we have
seen in Helsinki. Leading the development and
transformation of a unit acting in the interest
of the people is hard! “To be a king and wear a
crown is a thing more glorious to them that see
it than it is pleasant to them that bear it.“ (The
Golden Speech – Queen Elizabeth I).
Under the current leadership the department
performs more than 3200 operations per year,
including 500 vascular cases, 700 tumors, 1000
spine operations, 600 moderate and severe
brain injury patients and 300 shunt and ven-
triculostomy operations. Also they receive well
in excess of 100 visitors a year, including many
illustrious and leading figures of neurosurgery,
such as Professor Gazi Yaşargil who demon-
strated his skills and microsurgical techniques
in Helsinki during 2001-2003, Prof. Vinko Do-
lenc, Prof. Ossama Al-Mefty, Prof. Ali Krisht,

305
Prof. Uğur Türe, Prof. Duke Samson, and Prof.
Alexander Konovalov.
It was an honour and pleasure to be a witness
and participant of the ceremony of the award
of the PhD thesis for Dr. Martin Lehecka on
February 6th 2009. In keeping with local tradi-
tion the ceremony and meaningful pageantry
began with a defense of his thesis witnessed by
a great audience. His opponent for the day was
perhaps the world‘s most famous neurosur-
geon, and certainly one of the most published,
quoted, accomplished and skillful surgeons of
all time Prof. Robert Spetzler. In keeping with
the Helsinki neurosurgery trademark, Prof. Juha
Hernesniemi performed a surgical clipping of a
complex pericallosal artery aneurysm in hon-
our of Prof. Spetzler who was the star mem-
ber of the audience. The typically successful
operation carried out in just over 24 minutes
was marked by great mutual respect they had
for each other. Prof. Spetzler marked the occa-
sion by his testimony in the visitor‘s book and
in his speech during the ceremony. He stated
in the ceremony that following his travels to
many neurosurgical units and observing many
operations and surgeons, after seeing neuro-
surgery by Professor Hernesniemi that “he had
never seen better surgery!“ Such comments are
often made by many visiting surgeons, or dur-
ing the annual LINNC meeting or Live Course in
Helsinki. However, most noticeable was the re-
spect, sincerity and magnanimity towards each
other, maybe mutually recognising the passion
and drive felt as evident by the sufferings en-
dured, and their achievements.
I heard and noted on precious occasions Pro-
fessor Hernesniemi council some visiting young
and aspiring neurosurgeons. He would advise
them that “when planning your career, find a
senior neurosurgeon to tutor and mentor you.
They may be in your own institute, or far away
in other parts of the world. While you need the
help of many different people, try to find one
that you can talk to about your failures, fears,
plans and hopes. He or she may be the chair-
man of the institute, but he or she can also be
the one who has a great soul and understand-
ing of life - and neurosurgery.“ He would say
that “Without the help of a tutor it is extremely
difficult to become a skilled neurosurgeon, and
impossible to make an academic career. The
life work of Professor Yaşargil with his books
and operations has been my main teacher, fol-
lowed by Profs. Drake and Peerless. Many use-
ful operative techniques and tricks have been
achieved and copied by sitting in the cold cor-
ners of various operating rooms in Europe and
Northern America.“
There were many wonderful late evenings in
the conference room during on-call days when
we were treated to happy and sad tales from
the past and pearls of wisdom. During these
sessions other names and institutions we heard
him mention about his influences included col-
leagues in Bucharest (Arseni, Oprescu), Zürich
(Yonekawa), Budapest (Pasztor, Toth,Vajda),
London (Symon, Crockard), Montreal (Ber-
trand), Mainz (Perneczky), Little Rock (Al-
Mefty, Krisht), and Utrecht (Tulleken). In his
native country there have been many strong
influences on his present practice in many dif-
ferent ways. They include Drs. O. Heiskanen, L.
Laitinen, I. Oksala (cardiac surgeon), S. Nys-
tröm, S. Pakarinen, H. Troupp and M. Vapalahti.
It was always clear to me that, no matter what,
he loved and respected his mentors, particu-
larly Yaşargil, Drake and Peerless.
For the members of The Rainbow Team lets
hope that we all one day appreciate that our
mentors and teachers have always loved us, no
matter how well or badly it was expressed. It
was the best we received at the time, and it is
for us to do better. Often we as fellows saw the
gratitude expressed towards Juha by patients
and their relatives because of yet another life
saved or changed for the better. They came
from France, Norway, Russia and other lands
where the word had spread. It was also well
known for Juha to travel to other countries to

306
perform major operations. This was without
any private or financial reimbursement. That
meant no money what so ever being paid to
him or other staff for such cases whether oper-
ated at home or abroad. And there have been
countless such cases!
Months after my arrival in Helsinki following
very limited socialising outside of work, I met
a young lady in a social gathering. Her name
was Anisa and her father was a patient cared
for by Professor Juha Hernesniemi more than a
decade ago. It was inspiring and joyful to hear
the gratitude and love felt towards Juha and
the team by this lady. Sadly her father did not
survive following his subarachnoid hemorrhage
despite all efforts, which had included bypass
surgery. She expressed her great and lasting
gratitude, and had only praise and admiration
for the care and support they received from
Juha Hernesniemi and his team.
It is with the hope of giving the best care pos-
sible for our patients and their families that we
suffer, learn, question, and better ourselves. We
provide this book as a brief revision and insight
for those visitors coming to Helsinki and seeing
Professor Hernesniemi‘s methods.

307

308
8.9. TWO MONTH FELLOWSHIP –
ROD SAMUELSON (RICHMOND, VIRGINIA)
Many people visit the Helsinki University Cen-
tral Hospital Neurosurgery Department each
year for a relatively short period of time – rang-
ing 1 week to 3 months. In the following pages,
I share my experience from a two-month visit
in January and February 2010.
My visit to Helsinki came immediately after my
graduation from Neurological Surgery Residen-
cy. I came to work with Dr. Hernesniemi to get
additional experience in complex intracranial
procedures before an open cerebrovascular fel-
lowship. My expectations before I arrived were
to see perhaps one or two aneurysm cases per
week. A few other cerebrovascular cases, such
as AVM resection, would have been a big bo-
nus. However, these expectations were quite
modest when compared to the 27 aneurysms,
7 AVMs, and 3 EC-IC bypasses from 86 total
operations during the seven weeks of my visit.
Without a doubt, the highlight of my visit was
the opportunity to scrub in for a basilar apex
aneurysm clipping.
The protocol in the OR allowed for two people
to scrub in with Dr. Hernesniemi at one time.
While this usually meant the fellows, the visi-
tors were allowed to scrub in when there were
no two fellows available. They could also scrub
in with the other attending surgeons if there
was not a resident assisting with the case.
My first and strongest impression of Dr. Her-
nesniemi‘s operations was how quickly he
completed the operations. However, he was
never “hurried,“ and the speed of the operation
was not – in itself – the goal. Rather, it was a
reflection of the organization and efficiency of
his operations, and the expertise of his entire
surgical team.
Much of the overall operative efficiency came
from the optimization of many small steps
throughout the operation. Of these, the more
concrete refinements are described in detail
elsewhere in this book. However, the many “in-
tangible“ aspects of these operations are diffi-
cult to describe adequately. They have resulted
from Dr. Hernesniemi‘s thirty years of high-vol-
ume surgical experience. For example, his ma-
nipulationsoftissuealmostalwaysachievedthe
desired effect on the first attempt. His choice
of instruments or aneurysms clips was almost
always correct, and each instrument was used
in a variety of ways before it was changed for
the next one. The summation of all of these lit-
tle refinements was rapid, nearly flawless sur-
gery. The “common“ operations were so highly
polished that even the sequence of instruments
that Dr. Hernesniemi used was predictable, and
the scrub nurses often had the next instrument
ready without a word being spoken.
Observing and discussing these high level op-
erations was the focus of my visit. Although
I was welcome to join the team on rounds,
it was not expected. The majority of patient
care was done in the Finnish language, but Dr.
Hernesniemi occasionally took the visitors on
afternoon teaching rounds, in English. The de-
partment also met each morning at 8:30 for
the radiology rounds. This was also in Finnish.
Therefore, during my two months in Helsinki, I
only attended this morning meeting during the
first week. I found plenty of opportunity during
the day to review the imaging for the impor-
tant cases.
In addition to the operations, there were a
number of other ways that I learned more
about microneurosurgery during my visit. Dr.
Hernesniemi credits his microsurgery train-
8 | Visiting Helsinki Neurosurgery | Rod Samuelson

309
Figure 8-15. The OR library.
Figure 8-16. The OR meeting room.
Rod Samuelson | Visiting Helsinki Neurosurgery | 8

310
ing primarily to Dr. Yaşargil and Dr. Drake, and
their classic textbooks, or his experiences with
them, was mentioned nearly every day. I spent
many hours with him listening to his insights
from the recent surgical cases or his past ex-
perience. He also gave thoughtful responses to
every question that I had.
I spent many evenings and weekends read-
ing through the neurosurgery textbooks in the
main gathering room of the OR suite. Five or
six books, in particular, have received consider-
able attention from the residents and visitors,
and reading them in the context of Dr. Her-
nesniemi‘s teaching seemed to give them a
higher level of meaning. These books included
the volumes of Yaşargil‘s book series, the book
on vertebrobasilar aneurysms that Dr. Hernes-
niemi co-wrote with Dr. Drake and Dr. Peerless,
as well as Dr. Sugita‘s and Dr. Meyer‘s micro-
neurosurgery atlases.
There were also a number of surgical videos
and presentations that have been prepared by
the department. Visitors are free to download
this material. There was also opportunity to
prepare the videos and imaging from the cases
that I observed during my time in Helsinki. The
OR staff provided additional information that I
needed. For example, I received a copy of the
instruments in Dr. Hernesniemi‘s micro-instru-
ment tray, and one of the scrub nurses helped
me translate it from Finnish into English.
In conclusion, visiting Dr. Hernesniemi and the
Helsinki Central Hospital Department of Neu-
rosurgery was a one-of-a-kind opportunity to
observe microneurosurgery at its best. I recom-
mend it for anyone with an interest in opti-
mizing their own cerebrovascular neurosurgery
skills.
8 | Visiting Helsinki Neurosurgery | Rod Samuelson

311
Rod Samuelson | Visiting Helsinki Neurosurgery | 8

312
8.10. MEMORIES OF HELSINKI –
AYSE KARATAS (ANKARA, TURKEY)
In 2003, when I was in Amsterdam as a trainee
on the EANS course, I had a chance to meet
Prof. Juha Hernesniemi. I was very impressed
by the aneurysm and AVM operation videos he
presented. He was using quick and clean sur-
gical technique on very complicated cases. He
was able to perform a high number of micro-
neurosurgerical operations. After the lecture,
all trainees, including me, wanted to talk with
him. He ran out of his business cards complete-
ly due to a high demand, but was so kind to get
one for me. Not only his professional abilities,
but also his humble personality affected me
very much. I thought to myself: "I should learn
cerebrovascular neurosurgery from him".
I went to Helsinki in November 2003 for the
first time. I arrived at Helsinki airport at mid-
night. First, I had to go to Töölö Hospital to pick
up the key and the map of the apartment where
I would stay. However, I did not know exactly
where the hospital was. I was lucky, and when
I got on the Finnair city bus, Prof. Hernesniemi
also got on the same bus coming from a do-
mestic flight. I felt very relaxed after seeing and
talking to him. We went to the hospital togeth-
er. He called me a taxi and gave me a bus card
for the next day. I stayed just for one week. I can
remember very well my first day in Helsinki. He
operated five cases (one basilar aneurysm, two
middle cerebral artery aneurysms, a craniophar-
yngioma and a colloid cyst). He was on call that
day, and even operated a lumber disc herniation
with cauda equina syndrome on the same night.
During that week, I was fortunate to assist him
in 13 operations (one of them was an ELANA
bypass and another one a trigonal AVM). Dur-
ing that period, Dr. Keisuke Ishii from Japan was
also there as a fellow. Later on, I started as a
clinical and research fellow on the 1st of August
in 2004, with the support of CIMO scholarship
for international post-master‘s level studies and
research at Finnish universities. I stayed in Hel-
sinki for a year. During this period, I assisted him
in 357 microsurgical operations. I edited and an-
alyzed a high number of operative videos during
the weekends. We were watching these videos
during the breaks between the operations and
discussed them with him. I was also involved in
many research projects, especially on cerebral
aneurysms. I appreciate Dr. Mika Niemelä, Dr.
Juhana Frösen and Dr. Anna Piippo for their col-
laboration in these research studies.
The Department of Neurosurgery in Töölö Hos-
pital of Helsinki Universal Central Hospital is a
referral center for complicated cerebrovascular
cases in Finland and also other countries in Eu-
rope. In Töölö Hospital, most of the aneurysms
are clipped. They also have a very experienced
neuroradiology team. I respect Dr. Matti Porras,
and cannot forget him standing and observing
for many hours during AVM surgeries in the
operating room. All anesthesiologists and nurs-
es have also dedicated themselves to neuro-
surgery.
Prof. Juha Hernesniemi is a very hardworking
surgeon. Although I have graduated from An-
kara University Department of Neurosurgery
in Turkey, which is famous for its intense cur-
riculum, it was really difficult to keep up with
his busy schedule. He was sending emails to
me about his daily work. I noticed that the first
email was sent at 5.00 AM in the morning. I
went to the hospital at 7.00 AM. We visited the
ICU, and then attended the radiology meeting.
Operations started at 8.30 AM. We were oper-
ating 3-5 cases a day. He was doing fast but
safe surgery. He is a very good role model for a
young neurosurgeon. I learned from him many
important tricks during every step of the sur-
8 | Visiting Helsinki Neurosurgery | Ayse Karatas

313
gery. We were using ”four-hand-microneuro-
surgery” as he called it. He was very helpful and
empathetic for the visitors, since he had stayed
abroad for many years himself. He became not
only my mentor, but also a good friend for me
during my stay. I remember my last day in Töölö.
I walked with Prof. Hernesniemi to the exit door
of the hospital while he was going home. On
that day, the hospital flag was at half-mast be-
cause one of the nurses had died. It was already
a sorrowful day for us, so we could not talk to
each other. He could only tell me that he had
sent me an email. I will forever save that email
which is really important for me.
I am honored to have met and worked with
Prof. Hernesniemi. I would like to thank him for
his support that he gave me.
Ayse Karatas | Visiting Helsinki Neurosurgery | 8

315
by Juha Hernesniemi
It is difficult to select trainees to become fu-
ture neurosurgeons. We should pick young
people with so much dedication, determina-
tion and full of energy that one day they will
become far better than what we are. In my de-
partment, this selection is mainly based on my
foresight that, one day, this particular young
person will amaze me with both creativity and
skillful performances. I hope, that with time
some of these youngsters will become the best
neurosurgeons in the world.
They must be young because the learning peri-
od is long, a whole lifetime! They must be intel-
ligent, flexible, they must get well along with
very different people. At the same time they
must have a somewhat stubborn and tenacious
character to fulfill their goals, often against
the wishes of other people, sometimes even
the chairman. They must be able to travel, and
they must be fluent in the main languages of
the international neurosurgical community, so
as to be able to visit departments all over the
world to learn new ideas and techniques. They
have to be hard working and have good hands,
irrespective of their glove size. It is extremely
helpful to be in good physical and mental con-
dition, by doing some sports or other hobbies
which help to quickly recover from the many
failures and complications encountered in eve-
ryday work.
A good healthy sense of humor helps, and it is
important to have the support of the family or
good friends in all the daily joys and sorrows.
Cynicism and black humor alone, will probably
not be able to carry someone through the years
of hard work, rather he or she will experience
burn out sooner or later. The new trainees must
realize from the early beginning that reaching
a high professional level comes at the expense
of long working hours and one is never truly
free from the work. If possible, they should
transform their work also into their hobby as
that helps in maintaining the interest in the
field for long periods of time.
I would like to share some of my thoughts and
reflect on some of my experience about the is-
sues a young neurosurgeon should be aware of
and maybe give little advice on how to over-
come some of the difficulties.
Some career advice to young neurosurgeons | 9
9. SOME CAREER ADVICE TO YOUNG NEUROSURGEONS

316
9.1. READ AND LEARN ANATOMY
To become a better microneurosurgeon, one
should constantly study microanatomy of the
brain as better knowledge of microsurgical
anatomy leads to better surgery. With beauti-
ful CT, MRI and angiography images of today,
learning central nervous system anatomy is far
easier than in the times of PEG, ventriculog-
raphy and surgery without microscope. Read-
ing the many textbooks available gives us the
opportunity to share the accumulated experi-
ence of several generations of neurosurgeons.
Preparing yourself for some new or infrequent
operation by reading, means that during the
actual surgery your hands will be guided by
those who had previously accumulated much
more experience on this particular procedure.
By reading frequently you may save, first and
foremost, your patient, but secondly also your
time and your nerves. It is not enough to learn
the anatomy once, rather, one is forced to re-
visit the same topics over and over again before
acquiring appropriate expertise in the matter.
Reading is hard work – and learning anatomy is
even harder. It is a lifetime job, or more!
9.2. TRAIN YOUR SKILLS
Neurosurgery is no different from any sports or
arts; only hard practice gives good results. Go to
the microsurgical laboratory to dissect animals
and cadavers if possible. Knowing anatomy and
the different tissue properties results in better
surgery. Train your hands in the laboratory set-
ting in increasingly demanding tasks. Operat-
ing under the microscope should be started in a
safe laboratory environment with enough time
to familiarize oneself with all the instruments,
devices and techniques, not to mention to de-
velop the necessary hand-eye co-ordination.
Many of the movements we perform with our
hands under the large magnification of the
microscope should become automatic, with-
out the need to concentrate on them, like e.g.
placing microsutures. Practice special tricks in
handling difficult situations, atraumatic ma-
nipulation of different kinds of tissues includ-
ing the tiniest arteries and veins, dissection of
important vascular and neuronal structures,
and understanding the 3D relationship of dif-
ferent structures. It is possible to train most of
the steps for any operation whether for vascu-
lar, tumor or spinal surgery in the laboratory
setting. Not necessarily as a single procedure
but as a collection of different techniques.
9.3. SELECT YOUR OWN HEROES
When beginning your career, select your own
heroes. They may be in your own institute, or
far away, in other parts of the world. While I
was visiting the maestros and sitting as an ob-
server in the corners of various cold operating
rooms around the Europe and North America
for altogether more than two years during my
early career, I always dreamt of the day that
I would be doing the same kind of high level
microsurgery. During one of my numerous visits
to Professor M.G. Yaşargil nearly 30 years ago,
a young Mexican neurosurgeon told me “One
day we might do even better!“ At that time
I found it hard to believe him, but now, with
retrospect I know that he was right. The same
happens in sports, arts, and technical develop-
ments, the younger generations do better as
they can stand on the shoulders of older ones.
Or not stand – they should begin their quest
from a new starting point, the point where
these earlier giants finished.
When planning your career, find a senior neu-
rosurgeon to mentor you. While you will need
the help of many different people, try to find
9 | Some career advice to young neurosurgeons

317
one to whom you can tell about your failures,
fears, plans and hopes. He or she does not have
to be the chairman of the institute, but he or
she should be the one who has a great soul
and understanding of life - and neurosurgery.
Without the help of a good tutor it is extremely
difficult to become a skilled microneurosur-
geon, and almost impossible to make a real
academic career.
9.4. KEEP FIT
Keep your body fit with regular exercise. Do-
ing several hundred operations a year is both
physically and mentally demanding, so try to
find hobbies outside of the operating room to
balance it out. This is easily said, but at least I
have had big difficulties to follow these rules.
You should do everything you can to avoid
fatigue, burn-out and cynicism towards your
work. Remain a fighter, never give up; if you
were thrown against a smooth wall, you should
hold to it with fingers and nails like a cat. Keep
up with mental training all the way throughout
your career. Even close to or after your retire-
ment you can still be useful, as you can contin-
ue to share your experience with younger neu-
rosurgeons. With age you will slow down; you
should respect this and behave accordingly.
But neurosurgical skill and experience remain,
something which is difficult if not impossible
to achieve in a short time. Experienced neuro-
surgeons, unlike experts in e.g. the information
technology field, are not pushed aside as easily
by the next generation. Ars longa, vita brevis,
occasio praeceps, experientia fallax, iudicium
difficile.
Figure 9-1. On the footsteps of a giant. Prof. Hernesniemi watching closely Prof. Yaşargil operating.

318
9.5. BE A MEDICAL DOCTOR, TAKE
RESPONSIBILITY!
Be a medical doctor when treating your pa-
tients! Don‘t hide behind the back of other
neurosurgeons to save your own face. You have
the responsibility for the patient, not for your
untarnished surgical series. Within a busy in-
stitute one can easily build up a reputation of
excellent surgical results by avoiding the high-
risk patients and passing them on to others.
With extreme selection of suitable cases, many
patients will be excluded and die without ever
being given a chance to survive - and this only
to save the good outcome figures for one‘s sur-
gical series. Superficial analysis of results from
some institution may give you the wrong pic-
ture regarding the skills of a particular neuro-
surgeon, the one with the worst results may
actually be the best, as he or she may be tack-
ling the most difficult cases, thus facing the
most difficult complications.
9.6. LEARN YOUR BEST WAY OF
DOING YOUR SURGERY
Find your own best way to work, select your
(few) favorite instruments (like e.g. the “little
thing“, i.e. a small dissector used by Dr. Drake
to push aside the aneurysm dome) and trust
them. Be open to new techniques and instru-
ments. Try them out and if you find them good,
adopt them. As Dr. Drake said, “much of the
merit of an approach is a matter of surgical ex-
perience“. He advised to make operations sim-
pler and faster and to preserve normal anatomy
by avoiding resection of the cranial base, the
brain or by sacrificing the arteries and veins. All
this results in better outcome for the patients,
the only thing that really matters. You should
try new treatment methods if you suspect that
Figure 9-1. ”One day we might do even better!“ At Weisser Wind in Zurich in 1982 (photo from Prof. Hernesniemi‘s
personal archive).

319
they might beat the old ones. But while read-
ing various reports on new techniques with
excellent results, be critical and believe your
own figures; after all it is you providing the
treatment, not the author of the publication.
Furthermore, don‘t change your methods if you
are performing well!
A clear evaluation of your own skills could be
stated in the following way: “Would you feel
safe to be operated on by yourself?“ If not, de-
velop your skills further, study and learn from
those who are better! In my opinion, with a
more active approach towards microsurgery,
intensive care, imaging, rehabilitation and
changes in mental attitude, we have made sig-
nificant progress as compared to the 1970‘s,
the time when I started my career. The annual
number of operations per neurosurgeon has
clearly increased. We have become more effi-
cient, and the work, which is done well at a
brisk pace, with greater experience, usually re-
sults in better outcome. In a way, I must agree
with Jehovah‘s witnesses, clean surgery with-
out blood loss is the fastest and safest way for
the patient, and also for the staff.
9.7. OPEN DOOR MICROSURGERY
Go to congresses, give lectures and participate
in discussions. But in addition you should also
visit different departments, both home and
abroad. Lectures in congresses give only a sim-
plified picture of the actual level of neurosur-
gery at a particular institution. Unfortunately,
the true results are often worse than those pre-
sented. Accept visitors. When doing so you get
a great chance to learn and to be criticized by
intelligent people who may have quite a differ-
ent experience and different ways of thinking.
With the constant presence of these observ-
ers you will be forced to perform on a much
higher level than if you were operating just by
yourself. Since 1997, I have been privileged to
have a large number of excellent international
fellows and visitors, who have taught me often
more than what I felt I could teach them. Ques-
tion, argue and discuss your daily routines. Tol-
erate different people and innovative thinking,
but also stick to your old habits if proven good.
When you go to visit neurosurgeons with ex-
cellent or new skills, you may learn much more
in a few days than from traveling to tens of
congresses and listening to hundreds of pres-
entations. When traveling, try to adopt all the
good things, even the small details. Of course
this is not always possible due to economical,
religious, or other factors that, perhaps, may
be even related to your own surgical skills. You
should travel throughout your career, as a resi-
dent, as a young neurosurgeon, and even later
on as an already experienced specialist - you
are never too old. Try to remain enthusiastic
about learning new things, but remember that
hard work and suffering is also a part of the
learning process.
9.8. RESEARCH AND KEEP RECORDS
Remain critical towards your own results; that
is the only way how to improve. Analyze your
own cases immediately after the surgery; “why
did it go so badly, why was it so smooth?“ Write
it down in your operative notes, track sheets or
database, but make sure to record your find-
ings. Our memory is short, only few months or
even less if the number of cases is high. You
should not be desperate if you don‘t have the
top facilities, because it is the actual work that
counts the most. The paper track sheets of Drs.
Drake and Peerless, primitive from the present
perspective, could still serve as a testimony of
surgical experience and techniques for the up-
coming generations.
Make videos and photographs, analyze them,
draw if you can, and discuss the cases with
other neurosurgeons, residents and students.
When recording your operations, you will find
that you end up doing better and cleaner mi-
crosurgery. Analyze your cases also in your
mind in the evenings or even during the sleep-

320
less nights. Perform mental exercises in how to
improve your surgery, which moves to omit or
to add. Share your experience with others, es-
pecially with younger people, and speak openly
about your complications. Being open means
honest surgery, and the truth helps always also
the patient. Do not brag in advance about how
simple a particular case will be (“…even my
mother could do it…“) as in this very same case
you may end up having the most surprising and
horrifying complications!
Dr. Drake stated in his book on vertebrobasilar
artery aneurysms: “If only we could have back
again many of those who were lost or badly
hurt, for a second chance in the operative room
with what we have learned.“ With an individual
patient we cannot have a second chance, but
this chance is given to the next patient if we
keep all of our experience in our memory and
databases, analyze it and use it well.
9.9. FOLLOW UP YOUR PATIENTS
You should keep track of your own results. Fol-
low up your patients with postoperative check-
ups on a regular basis, with outpatient visits,
letters, telephone calls, and hospital records
and add this follow-up data to your database.
You should have your own personal small data-
bases to keep track of your own surgical skills;
it is only fair to your future patients if you
know what the risks are of you performing a
particular operation. If there is somebody close
by who can do it better, let him or her operate
on the patient, and meanwhile enhance your
skills by observing, reading and practicing in a
laboratory. You should not settle for mediocre
results, always aim for the best standards of
treatment! Mistakes happen, but don‘t make
the same mistake twice. Discuss and analyze
your cases with others, ask for advice to avoid
future complications or disasters.
9.10. WRITE AND PUBLISH
Publish your results but don‘t publish every-
thing! We should remember Francis Bacon‘s
(1561-1626) words, cited on the first page of
Dr. Drake‘s book “Every man owes it as a debt
to his profession to put on record whatever he
has done that might be of use to others“. “One
or two good papers a year in good journals are
enough“ was Dr. Drake‘s advice. In the present
explosion of knowledge we should be very crit-
ical about what is published; only high quality
data with good analysis and proper message.
When publishing, we should look for relevant
literature and not neglect the original works
of the pioneers or the most important works
on the subjects. Writing and publishing is hard
work, it has to be practiced in the same way as
surgical skills. The true skill comes only with
time and numerous publications. Excuses like
“I‘m too busy with my clinical work to write…“
are out of place. In neurosurgery, everybody is
generally busy with his or her clinical work,
which is the reason why writing is so hard.
But despite the difficulties, writing is time well
spent. Before putting any ideas on the paper,
one is forced to analyze the problem to the
smallest detail so that it can be communicated
to others in a simplified and condensed way,
often resulting in new ideas. The other ad-
vantage that comes from writing is that one
becomes also a much better and more critical
reader, who is able to distinguish a good pub-
lication from a poor one at a glance. Finding
the proper balance between writing and actual
clinical work is one of the most difficult tasks
in academic neurosurgery.

321
9.11. KNOW YOUR PEOPLE
We are not alone when doing surgery. Treat
all your staff members, such as anesthesiolo-
gists, neuroradiologists and nurses, well. Know
their names, be familiar with their strengths
and weaknesses, and adjust your surgery to the
team you have available at that very moment.
If the team is less experienced, as is often the
case during the night, you must weigh the
risks and benefits of doing a particular proce-
dure at that time as opposed to doing it some
other day with a better-qualified team. Many
things affect your work: patients, their rela-
tives, nurses in the OR, intensive care and bed
wards, other neurosurgeons, anesthesiologists,
other surgical specialists, referring doctors, ad-
ministrative people, politicians, the society, and
even your international colleagues. You will es-
tablish your reputation based on many factors,
not only the success in surgery. Good reputa-
tion is hard to build, it takes years and years
of work, but it can be swept away in a short
instant if you drop your standards. On the other
hand, with good reputation one can withstand
many difficult situations and complications as
long as the level of work is kept at the highest
possible level. You must continuously monitor
your own work: postoperative angiograms, CTs,
and MRIs should be ordered and analyzed by
yourself and your staff, otherwise someone else
will order them. It is technically much easier to
e.g. replace an aneurysm clip soon after a failed
clipping or to remove a small tumor remnant
observed on a postoperative image, compared
to the abhorring thoughts of all the dangers
and psychical stress to the patient if it has to
be done after a longer period by someone else.
In order to avoid malpractice charges one of
the key points is to be open and honest, and to
carry out postoperative controls.
9.12. ATMOSPHERE
The atmosphere in the department should be
open and supportive of good work, and the
employees should be proud of their clinic. In-
ternal education of young doctors and nurses is
a must; they will better understand the whole
workflow of the department and they will be-
come more open to helping their colleagues
in need. Be honest! The staff has the right to
know what happened to patients who expe-
rienced complications; otherwise rumors will
destroy the atmosphere.
We should know our people, be kind but de-
manding. Do it in your own personal way, not
in the ways some consultants or books on ad-
ministration tell you to. Express your apprecia-
tion of your hardworking colleagues; pay them
well if you can. It is a pity that in the socialized
system of Scandinavian medicine this is seldom
possible. Many neurosurgeons are passionate
workers by nature, but being paid enough is
also important. But above all, try to be a role
model of a hard working professional who
takes justified pride in his or her own work and
who is continuously trying to improve his or
her work.

323
Life in neurosurgery: How I became me – Juha Hernesniemi | 10
“You are not famous“, said Professor Yaşargil
to me when visiting Helsinki 10 years ago. I
thought “Maybe not famous but good...“, to
contain my self-confidence - I do know all
aspects of the difficulties related with working
in a small country – but also its benefits...
I was born in 1947 in a very small village of
Niemonen, a part of Kannus in Ostrobothnia,
Western part of Middle Finland. My father
spent 5 years of his youth as a soldier in the
Second World War, when Finland was attacked
by the former Soviet Union. Later, he became a
teacher and our family settled down in Ruove-
si, a small beautiful country village 250 kilom-
eters north of Helsinki where I went to school.
I decided to become a medical doctor back in
Ruovesi due to the influence of Dr. Einar Filip
Palmén, a general practitioner (1886-1971),
who treated alone all the 10,000 people living
in this area for 50 years. We became friends
through hobbies, like collecting stamps, coins
and butterflies. I was doing also gymnastics,
and my heroes were Boris Shaklin from Soviet
Union and Yukio Endo from Japan. Later as a
schoolboy, I went to work in a factory in a small
German city called Lünen, and I noted that I
have very quick and skillful hands. During this
stay, I also hitchhiked to Austria and Switzer-
land, and visited Zürich for the first time. At
that time I had no idea how much influence this
town would eventually have on me.
After I graduated from high school in 1966, I
applied to the Medical Faculty in the Univer-
sity of Helsinki but failed. Looking back, this
turned out to be the best thing that could have
happened to me at that time. I had to go to
study elsewhere, so I applied to study medi-
cine in Zürich, Switzerland. In Zürich I became
a real European, even an international person.
I learned to work hard in a Swiss and inter-
national way, and I saw the value of detailed
knowledge of anatomy. I still regularly study
the book of Topograhical Anatomy by Professor
Gian Töndury, even though it is more than 40
years since I opened this book for the first time.
During my studies, I worked for more than two
years at the Brain Research Institute lead by
the hard-working Professor Kondrad Akert,
focusing on experimental neuroanatomy. Not
only did I see the high level of basic research,
but even more importantly, I learned how to
use an operating microscope, OPMI1. Further-
more, I also learned some ‚broken‘ English in
this very international team.
Eventually, I realized that basic research was
not for me, and so, after attending the lectures
of Professor Hugo Krayenbühl and Professor
M. Gazi Yaşargil, I decided to become a neuro-
surgeon. I asked Professor M. Gazi Yaşargil if I
could join his team in Zürich. He accepted my
request. But at that time, after having spent
seven years in a foreign country, I became very
much homesick, so that I had to forget my plans
about joining Professor Yaşargil, and moved
back to Helsinki instead. This was providential,
as two of my Scandinavian friends could not
manage the demanding training in Zürich clin-
ics. Why did I end up in neurosurgery? My sec-
ond interest, cardiac surgery, necessitated first
training in general surgery, and this seemed
way too long for me before entering cardiac
surgery itself. But one thing I adopted from
cardiac surgery, a one-hand knot I learned from
the great cardiac surgeon Professor Åke Sen-
ning in Zürich. I still use this knot when oper-
ating under the microscope. Psychiatry, a third
10. LIFE IN NEUROSURGERY:
HOW I BECAME ME – JUHA HERNESNIEMI

324
10 | Life in neurosurgery: How I became me – Juha Hernesniemi
Figure 10-1. Juha Hernesniemi with parents (Oiva and Senja) and younger brother Antti in 1950.

325
interest of mine made me to attend the famous
Manfred Bleuler‘s lectures but practice in psy-
chiatry in Finland and elsewhere proved ulti-
mately to be not very attractive to me. So even-
tually, I started my neurosurgical training in
Helsinki in 1973 under Professor Henry Troupp.
In 1966-73 even we, the very beginners at the
Zürich University, were aware that something
very special was happening in neurosurgery,
the rapid development of microsurgery by Pro-
fessor M. Gazi Yaşargil. As many neurosurgeons
in the world, I have been a student of his for
more than two thirds of my life, even if I was
living very far away for most of the time, but
at the same time, living so very close, as I was
learning from him and his work. Already as a
medical student I was aware of my geographi-
cally even more distant heroes in Canada,
Profs. Charles G. Drake and Sydney J. Peerless,
but it took a long time before I had the op-
portunity to visit and work with them. Some
other international neurosurgeons who have
influenced me in many ways are C.F. Tulleken,
Y. Yonekawa, H. Sano and R. Spetzler. Besides
these giants I have found also younger he-
roes, and I try very hard to learn and develop
all the time with them. A special credit I give
Mrs. Rosemarie Frick, who runs an experi-
mental laboratory for practicing microsurgi-
cal techniques in Zürich. Domestic colleagues
who have been most influential on my present
practice in many different ways have been (in
alphabetical order) Drs. Olli Heiskanen, Lauri V.
Laitinen, Stig Nyström, Seppo Pakarinen, Henry
Troupp and Matti Vapalahti. Outside of neuro-
surgery, Drs. Erik Anttinen (psychiatry and neu-
rology), Viljo Halonen (neuroradiology), Eero
Juusela (GI-surgeon), Aarno Kari (ICU), Markku
Kaste (neurology), Ulla Kaski (pediatrics), Ilkka
Oksala (cardiac surgeon), Teuvo Pessi (general
surgeon, ICU), Matti Porri (GP), and Jukka Taka-
la (ICU) have had a great influence on me.
Figure 10-3. Juha Hernesniemi with Finnish friends in Lünen, Germany, in 1964.

326
Figure 10-2. Dr. Einar Filip Palmén (1886-1971), a general practitioner in Ruovesi.

327
Neurosurgery is not different from sports or
arts, where only hard practice gives good re-
sults. The worst handicap in my early training
was the lack of a real microsurgical laboratory
practice, and the second was the lack of proper
anatomical studies in cadavers. I have several
times tried to correct this afterwards, but not
very successfully between my heavy flow of
surgeries. One definitely should devote time to
these studies already when training in neuro-
surgery.
I was trained in neurosurgery in Helsinki dur-
ing 1973-79, and made my Ph.D. in 1979 on
head injuries. Thereafter, I worked for some
months in Uppsala, Sweden, and then joined
Professor Matti Vapalahti in Kuopio, Finland.
I had the opportunity to operate on a large
number of patients with aneurysms, AVMs,
tumors and spinal problems, as the number of
neurosurgeons was initially very few. In fact,
we pioneered early aneurysm surgery in the
Nordic Countries. Our active and growing team
in Kuopio went to visit several important in-
ternational centers, and my own neurosurgical
techniques developed and improved further. In
the late 80‘s I noticed the lack of my own pub-
lications due to hard clinical work. I was then
allowed to establish the aneurysm database in
Eastern Finland, on which many publications
and our clinical experience were based.
I was not a visiting professor, but a research
and teaching fellow in Miami in 1992-93,
studying the vertebrobasilar aneurysms and
posterior fossa AVM series of Drs. Drake and
Peerless. This turned out to be a very important
factor for my later appointment as a full pro-
fessor and chairman in Helsinki in 1997, even
though this period was looked at with scepti-
cism by one of the leading British neurosur-
geons (“At the age of 45 he seems to be happy
to study surgeries of others“). Seventeen years
earlier in 1980, I had left Helsinki for Kuopio
because I was not allowed to do enough sur-
geries. At that time my teacher and chairman
Professor Henry Troupp asked me, “..if I would
ever come back..“. I answered promptly: “in 17
years“. I fulfilled my promise.
In 1996, there were only 1632 neurosurgical
operations in Helsinki, and the annual budget
of the department was 51 534 000 Finnish
marks (FIM) (about 10 million euros). The de-
partment had traditionally to put up with min-
imal resources, and saving money was a virtue
Figure 10-5. OPMI1 surgical microscope. Photo courtesy
of Carl Zeiss AG.
Figure 10-4. Juha Hernesniemi (left) training microsurgery
in Zurich in 1969 with Dr. Etsuro Kawana from Tokyo, Japan.

328
exceeding everything else. However, in three
years, after I became the chairman, the number
of operations and the budget had doubled (in
2000: 3037 operations, the annual budget 103
065 000 FIM). People in the hospital adminis-
tration, and even in the department found it
hard to believe. The justification of the quan-
tity and even the quality of treatment were
questioned, and an attempt to fire me was ini-
tiated. Consequently, I had to collect figures on
the activity at other neurosurgical departments
in Finland and the neighboring countries, es-
pecially Sweden and Estonia. An internal in-
vestigation by the administration continued
for more than a year, but finally disclosed that
the patient selection was appropriate and the
treatment results were of high quality. Nowa-
days, we are well supported by our hospital
administration and surrounding society as they
clearly see the value of our high quality work.
We are continuously evaluating our daily work
and the fate of our patients. Our main goal is
to serve our society in the best possible way.
The whole Helsinki Neurosurgery staff (doctors,
nurses, technicians and others) now consists of
more than 200 people, the annual budget is 26
million Euros, and the number of annual opera-
tions is 3200.
Since 1997, the number of publications has in-
creased steadily. Both our own staff but also
an increasing number of fellows and visitors
have been involved in clinical papers. Finland,
with a small population of 5.3 million but with
a very well developed infrastructure, is one the
few countries suited for reliable epidemiologi-
cal studies. The long-term follow-up studies of
Troupp and others since the Second World War
have thereafter been continued with several
great contributions to show the natural history
Figure 10-7. Juha Hernesniemi with Prof. Charles G. Drake in Miami in 1993.

329
Figure 10-6. Juha Hernesniemi working in hospital in 1972.

330
of AVMs, tumors and aneurysms. The Helsinki
Aneurysm Database is going to be finalized
at the end of this year, with more than 9000
patients with cerebral aneurysms treated. This
will increase certainly the number of the clini-
cal studies, and there are already several large
projects going on.
I had no special administrative training to
be a chairman. I have looked carefully in my
surroundings, and I have learnt a lot from my
father Oiva Hernesniemi, and from my former
chairmen Professors Kondrad Akert. Henry
Troupp and Matti Vapalahti. I have followed
Finnish General Adolf Ehrnrooth‘s advice to be
in front and middle of the staff (and always
present), to behave like Koskela in “Unknown
soldier“ of Väinö Linna, or Memed in “My hawk
Memed (Ince Memed) of Yashar Kemal. More
international heroes have been Cassius Clay
(Mohammed Ali) and Aleksandr Solženitsyn. It
is difficult to be as courageous as they, conse-
quently also Professor Drake‘s advice to do in
in your own way has been extremely helpful in
building up new Helsnki Neurosurgery.
What next?
Looking back, I say, as every busy neurosurgeon,
that I surely should have spent more time with
my family. Without their support I could not
have managed and become successful. On the
other hand I also would have liked to read more
books, learn more languages, traveled more,
and do more sports. The message is “carpe
diem“, life is short, “occasio praeceps“. I hope
that the good genes for health from my parents
continue to allow me to work, and I can spend
some 10 years more to develop microsurgical
skills further, to develop simpler bypass and
most important of all, to support the younger
generation to become better than we are. We
continue to have open doors in Helsinki, to do
open-door microsurgery and we welcome eve-
ryone to see and to learn. We learn from each
other when we share our cases. In the interna-
tional melting pot of Helsinki, hopefully better
and better soups will be cooked in the future.
Figure 10-8. Drawing of
Juha Hernesniemi in 2010
by Dr. Roberto Crosa from
Montevideo, Uruguay.

331
Figure 10-9. Riitta, Ida, Heta and Jussi Hernesniemi in Kuopio in 1984.

333
11. FUTURE OF NEUROSURGERY
by Juha Hernesniemi
In 1973 when I began my training in Helsinki,
our department was taking care of nearly en-
tire Finland, with a catchment area of around 4
million people. There were around 600 opera-
tions a year. Ten cervical spine, 50 aneurysm
and 100 tumor operations were performed
each year, and one chronic subdural hematoma
was drained every second week. Patients aged
more than 60 years were considered “old“ (!),
and were operated on only rarely. Over three
decades later, in 2007, we operated on 400
cervical spines, more than 300 aneurysms and
600 brain tumors; 256 chronic subdural hema-
tomas were drained. The number of traumatic
head injuries operated on in our unit is four
times higher than in 1973. The number of all
operations in Helsinki is nowadays five-fold
compared to the early 70‘s, and in the whole
country (there are nowadays four other neuro-
surgical units) it is ten-fold. The average hospi-
tal stay for a neurosurgical patient is less than
five days, and almost 40% of the operations
are performed in patients aged 60 or more.
The better results obtainable by microsurgery
have been increasingly subjected to critical
scrutiny by improved imaging, with the intro-
duction of CT in the late 70‘s and MRI in the
80‘s. Control images started to demonstrate
that many times the so-called “total removal“
was only a partial one, and some part of the
tumor or hematoma remained. They also made
visible terrible contusions or infarctions caused
by surgery, so well hidden in previous times
when only angiographic controls were per-
formed. There still remains a lot of room for
improvement in our microsurgical methods,
and it is certain that imaging is all the time
ahead of our microsurgical technique. Before
introduction of the surgical microscope and
modern imaging the atmosphere and attitude
were different, and neurosurgeon‘s own word
on total removal remained the only prove, in
addition to clips and tantalum powder placed
on the resection surface.
Intensive care and neuroanesthesia are now at
a completely different level than in the 70‘s,
when intraoperative herniation of the brain out
of the craniotomy opening was common, and
arterial blood pressure monitoring was a rarity.
Nowadays monitoring of intracranial pressure,
and even brain tissue blood flow and oxygena-
tion can be routinely implemented.
The biggest challenge in the future is to fig-
ure out how to treat most patients using the
best treatment modalities at the lowest cost.
Health-conscious living habits, proper nutri-
tion and physical exercise, together with the
avoidance of smoking, alcohol abuse and drugs
prolong life everywhere, at least in rich in-
dustrialized countries. Already now it is com-
mon to reach 80 years, and close to 100 years
is reality in the near future, but only few will
live to the biological maximum of 120. With
the increasing life expectancy, brain tumors,
vascular diseases and degenerative spine dis-
ease become more prevalent, and they are also
treated at an ever higher age. Imaging with
MRI, or some other new imaging modality, will
become ever more widely available in patient
treatment. Brain tumors will be found in early
stages of their growth. Giant tumors growing
silently for years will be rare because of early
check-ups. Patients coming to the doctor‘s ap-
pointment will have their whole body scanned,
and it will become difficult to evaluate and
treat all different incidental findings emerging
from these screenings. Every patient will have
Future of neurosurgery | 11

334
some or many different findings, and teams of
different specialists using databases will assess
the clinical significance of these. The magnetic
field strengths of MRI scanners will continue to
increase, and the tiniest structures will be seen,
even the effect and targets of pharmacological
therapy will become visible.
Traffic accidents will become extremely rare. In
1973 there were more than 1000 traffic-relat-
ed fatalities in this small country - nowadays
less than 300. In the future, even one death
in traffic will lead to big headlines. Different
alarm systems, localizers and navigators ena-
ble faster transport to treatment facilities, and
fewer succumb outside the hospital. Because
of improved and widely available imaging very
few will die of an undiagnosed slowly develop-
ing subdural hematoma; in the future none.
Prevention will be in the future the most com-
mon strategy in treating cerebrovascular dis-
eases. Even the smallest vessels can be seen
noninvasively, and also the wall thickness and
structure. Aneurysms and stenosis/occlusion of
the vessels will be treated by angioplasty and/
or local biological means.
Neurosurgeons will have an important role in
the endovascular treatment, and the knowl-
edge of long-term postoperative care is im-
portant. If surgery is needed, it will be done
through very small openings with the help of
different intraoperative imaging and record-
ings. Simple bypasses done under local anes-
thesia are common procedures: arteries and
even veins are connected to each other by sim-
ple artificial grafts for flow augmentation.
Operations will be practiced before the actual
surgery using simulators; in this way surprises
during surgery will become rare. Functional im-
aging shows accurately cortical functions, and
eloquent regions and tracts can be visualized
even during surgery. Skull will be opened us-
ing short scalp incisions and small cranial flaps,
intraoperative imaging will show the operative
trajectory and target all the time. Instruments
will be carried by micromanipulators and used
more securely than what our hands are capable
of, while removing the tumors or infarctions, or
applying sutures, clips, or glue. Large openings
of skull base surgery will disappear, and in gen-
eral the importance of open surgery will dimin-
ish in the treatment of brain tumors. Histology
of brain tumors will be confirmed by biopsy, but
in most cases diagnosis will be made based on
imaging without the need for biopsy. Main part
of tumors will be treated by stereotaxic irradia-
tion; removal of the tumor will become neces-
sary only to create space for eventual swelling.
Molecular treatments will destroy the tumor, or
slow down its growth so that the disease will
be under control for the whole life. Epileptic
foci will be inactivated or destroyed by irradia-
tion or medication, and similar principles will
be applied for functional neurosurgery.
In the neurointensive care units neurologists,
neurosurgeons, anesthesiologists and many
other specialists together will take part in
treating diseases of the brain. One individual‘s
experience and knowledge will no longer be
sufficient; only a team of professionals aided
by databases will be able to provide the best
possible care. The collected international treat-
ment experience is already in databases and
available, only money is needed. Hospitals are
business-based and, consequently, the highest
experience and skills may be expensive. Reha-
bilitation will be intensive and broadly utilized.
Stem cells or others will be used for the repair
of brain, spinal cord or nerve injuries. Genetic
and molecular causes of spinal diseases will
become better understood, and this will lead to
better treatment pain, as will also multidisci-
11 | Future of neurosurgery

335
plinary help in individual pain patients. Osteo-
genetic materials will reduce significantly the
present heavy spinal instrumentation and lead
to rather minimally invasive spinal surgeries.
Experience makes us more flexible, and luck-
ily the future remains unrevealed to us. Thirty
years from now, the present young generation
will work completely differently compared to
us; better and more efficiently. Our fine pre-
sent microneurosurgical performances will be
spoken of in future tales in the same tone, as
the cavalry of our famous ancient army, or the
heroic surgical days of Viipuri (Wyborg) County
Hospital are spoken of nowadays.
Future of neurosurgery | 11

337
APPENDIX 1.
SOME SELECTED ARTICLES ON MICRONEUROSURGICAL AND
NEUROANESTHESIOLOGICAL TECHNIQUES FROM HELSINKI
• Celik O, Niemelä M, Romani R, Hernesniemi
J. Inappropriate application of Yaşargil aneu-
rysm clips: a new observation and technical
remark. Neurosurgery 2010; 66 (3 Suppl
Operative):84-7.
• Celik O, Piippo A, Romani R, Navratil O,
Laakso A, Lehecka M, Dashti R, Niemelä M,
Rinne J, Jääskeläinen JE, Hernesniemi J.
Management of dural arteriovenous fistulas
- Helsinki and Kuopio experience. Acta Neu-
rochir Suppl 2010;107:77-82.
• Dashti R, Rinne J, Hernesniemi J, Niemelä M,
Kivipelto L, Lehecka M, Karatas A, Avci E,
Ishii K, Shen H, Peláez JG, Albayrak BS,
Ronkainen A, Koivisto T, Jääskeläinen JE.
Microneurosurgical management of proximal
middle cerebral artery aneurysms. Surg Neu-
rol 2007; 67:6-14.
• Dashti R, Hernesniemi J, Niemelä M, Rinne J,
Porras M, Lehecka M, Shen H, Albayrak BS,
Lehto H, Koroknay-Pál P, de Oliveira RS, Perra
G, Ronkainen A, Koivisto T, Jääskeläinen JE.
Microneurosurgical management of middle
cerebral artery bifurcation aneurysms. Surg
Neurol 2007; 67:441-56.
• Dashti R, Hernesniemi J, Niemelä M, Rinne J,
Lehecka M, Shen H, Lehto H, Albayrak BS,
Ronkainen A, Koivisto T, Jääskeläinen JE.
Microneurosurgical management of distal
middle cerebral artery aneurysms. Surg Neu-
rol 2007; 67:553-63.
• Dashti R, Hernesniemi J, Lehto H, Niemelä M,
Lehecka M, Rinne J, Porras M, Ronkainen A,
Phornsuwannapha S, Koivisto T, Jääskeläinen
JE. Microneurosurgical management of prox-
imal anterior cerebral artery aneurysms. Surg
Neurol 2007; 68:366-77.
• Dashti R, Laakso A, Niemelä M, Porras M,
Hernesniemi J. Microscope-integrated near-
infrared indocyanine green videoangiogra-
phy during surgery of intracranial aneurysms:
the Helsinki experience. Surg Neurol 2009;
71:543-50.
• Hernesniemi J. Mechanisms to improve treat-
ment standards in neurosurgery, cerebral
aneurysm surgery as example. Acta Neurochir
Suppl 2001; 78:127-34.
• Hernesniemi J, Ishii K, Niemelä M, Smrcka M,
Kivipelto L, Fujiki M, Shen H. Lateral supraor-
bital approach as an alternative to the clas-
sical pterionalapproach. Acta Neurochir Sup-
pl 2005; 94:17-21.
• Hernesniemi J, Ishii K, Niemelä M, Kivipelto L,
Fujiki M, Shen H. Subtemporal approach to
basilar bifurcation aneurysms: advanced
technique and clinical experience. Acta Neu-
rochir Suppl 2005; 94:31-8.
• Hernesniemi J, Ishii K, Karatas A, Kivipelto
L, Niemelä M, Nagy L, Shen H. Surgical tech-
nique to retract the tentorial edge during
subtemporal approach: technical note. Neu-

338
rosurgery 2005; 57(4 Suppl):E408.
• Hernesniemi J, Niemelä M, Karatas A, Kivi-
pelto L, Ishii K, Rinne J, Ronkainen A, Koivisto
T, Kivisaari R, Shen H, Lehecka M, Frösen J,
Piippo A, Jääskeläinen JE. Some collected
principles of microneurosurgery: simple and
fast, while preserving normal anatomy: a
review. Surg Neurol 2005 Sep; 64:195-200.
• Hernesniemi J, Niemelä M, Dashti R, Karatas
A, Kivipelto L, Ishii K, Rinne J, Ronkainen A,
Peláez JG, Koivisto T, Kivisaari R, Shen H,
Lehecka M, Frösen J, Piippo A, Avci E, Jääskel-
äinen JE. Principles of microneurosurgery for
safe and fast surgery. Surg Technol Int 2006;
15:305-10.
• Hernesniemi J, Romani R, Dashti R, Albayrak
BS, Savolainen S, Ramsey C 3rd, Karatas A,
Lehto H, Navratil O, Niemelä M. Microsurgi-
cal treatment of third ventricular colloid
cysts by interhemispheric far lateral trans-
callosal approach-experience of 134 patients.
Surg Neurol 2008; 69:447-53.
• Hernesniemi J, Dashti R, Lehecka M, Niemelä
M, Rinne J, Lehto H, Ronkainen A, Koivisto T,
Jääskeläinen JE. Microneurosurgical man-
agement of anterior communicating artery
aneurysms. Surg Neurol 2008; 70:8-28.
• Hernesniemi J, Romani R, Albayrak BS, Lehto
H, Dashti R, Ramsey C 3rd, Karatas A, Cardia
A, Navratil O, Piippo A, Fujiki M, Toninelli S,
Niemelä M. Microsurgical management of
pineal region lesions: personal experience
with 119 patients. Surg Neurol 2008; 70:576-
83.
• Hernesniemi J, Romani R, Lehecka M, Isarakul
P, Dashti R, Celik O, Navratil O, Niemelä M,
Laakso A. Present state of microneurosurgery
of cerebral arteriovenous malformations.
Acta Neurochir Suppl 2010; 107:71-6.
• Kivelev J, Niemelä M, Blomstedt G, Roivainen
R, Lehecka M, Hernesniemi J. Microsurgical
treatment of temporal lobe cavernomas. Acta
Neurochir 2011; 153:261-70.
• Korja M, Sen C, Langer D. Operative nuances
of side-to-side in situ posterior inferior cer-
ebellar artery bypass procedure. Neurosur-
gery 2010; 67(2 Suppl Operative):471-7.
• Krayenbühl N, Hafez A, Hernesniemi JA, Krisht
AF. Taming the cavernous sinus: technique
of hemostasis using fibrin glue. Neurosurgery
2007; 61(3 Suppl):E52.
• Langer DJ, Van Der Zwan A, Vajkoczy P, Kivi-
pelto L, Van Doormaal TP, Tulleken CA.
Excimer laser-assisted nonocclusive anas-
tomosis. An emerging technology for use in
the creation of intracranial-intracranial and
extracranial-intracranial cerebral bypass.
Neurosurg Focus 2008; 24:E6.
• Lehecka M, Lehto H, Niemelä M, Juvela S,
Dashti R, Koivisto T, Ronkainen A, Rinne J,
Jääskeläinen JE, Hernesniemi JA. Distal ante-
rior cerebral artery aneurysms: treatment
and outcome analysis of 501 patients. Neu-
rosurgery 2008; 62:590-601.
APPENDIX 1.

339
• Lehecka M, Dashti R, Hernesniemi J, Niemelä
M, Koivisto T, Ronkainen A, Rinne J, Jääskel-
äinen J. Microneurosurgical management of
aneurysms at A3 segment of anterior cer-
ebral artery. Surg Neurol 2008; 70:135-51.
aneurysms at the A2 segment of anterior cer-
ebral artery (proximal pericallosal artery) and
its frontobasal branches. Surg Neurol 2008;
70:232-46.
aneurysms at A4 and A5 segments and dis-
tal cortical branches of anterior cerebral ar-
tery. Surg Neurol 2008; 70:352-67.
• Lehecka M, Dashti R, Romani R, Celik O,
Navratil O, Kivipelto L, Kivisaari R, Shen H,
Ishii K, Karatas A, Lehto H, Kokuzawa J,
Niemelä M, Rinne J, Ronkainen A, Koivisto T,
Jääskelainen JE, Hernesniemi J. Microneuro
surgical management of internal carotid
artery bifurcation aneurysms. Surg Neurol
2009; 71:649-67.
• Lehecka M, Dashti R, Laakso A, van Popta JS,
Romani R, Navratil O, Kivipelto L, Kivisaari R,
Foroughi M, Kokuzawa J, Lehto H, Niemelä
M, Rinne J, Ronkainen A, Koivisto T, Jääskel-
äinen JE, Hernesniemi J. Microneurosurgical
management of anterior choroid artery
aneurysms. World Neurosurgery 2010;
73:486-99.
• Lehecka M, Dashti R, Rinne J, Romani R,
Kivisaari R, Niemelä M, Hernesniemi J. Surgi-
cal management of aneurysms of the mid-
dle cerebral artery. In Schmiedek and Sweet‘s
(eds.) Operative neurosurgical techniques,
6th ed. Elsevier, in press.
• Lehecka M, Niemelä M, Hernesniemi J. Distal
anterior cerebral artery aneurysms. In. R, Mc
Cormick P, Black P (eds.) Essential Techniques
in Operative Neurosurgery. Elsevier, in press.
• Lehto H, Dashti R, Karataş A, Niemelä M,
Hernesniemi JA. Third ventriculostomy
through the fenestrated lamina terminalis
during microneurosurgical clipping of intrac-
ranial aneurysms: an alternative to conven-
tional ventriculostomy. Neurosurgery 2009;
64:430-4.
• Lindroos AC, Niiya T, Randell T, Romani R,
Hernesniemi J, Niemi T. Sitting position for
removal of pineal region lesions: the Hel-
sinki experience. World Neurosurg. 2010 Oct-
Nov;74(4-5):505-13.
• Lindroos AC, Schramko A, Tanskanen P, Niemi
T. Effect of the combination of mannitol and
ringer acetate or hydroxyethyl starch on
whole blood coagulation in vitro. J Neuro-
surg Anesthesiol. 2010 Jan;22(1):16-20.
• Luostarinen T, Dilmen OK, Niiya T, Niemi T.
Effect of arterial blood pressure on the arte-
rial to end-tidal carbon dioxide difference
during anesthesia induction in patients

340
APPENDIX 1.
scheduled for craniotomy. J Neurosurg An-
esthesiol. 2010 Oct;22(4):303-8.
• Luostarinen T, Niiya T, Schramko A, Rosen-
berg P, Niemi T. Comparison of hypertonic
saline and mannitol on whole blood coagula-
tion in vitro assessed by thromboelastometry.
Neurocrit Care. 2011 Apr;14(2):238-43.
• Luostarinen T, Takala RS, Niemi TT, Katila AJ,
Niemelä M, Hernesniemi J, Randell T. Adeno-
sine-induced cardiac arrest during intraop-
erative cerebral aneurysm rupture. World
Neurosurgery 2010; 73:79-83.
• Nagy L, Ishii K, Karatas A, Shen H, Vajda J,
Niemelä M, Jääskeläinen J, Hernesniemi J,
Toth S. Water dissection technique of Toth
for opening neurosurgical cleavage planes.
Surg Neurol 2006; 65:38-41.
• Navratil O, Lehecka M, Lehto H, Dashti R,
Kivisaari R, Niemelä M, Hernesniemi JA. Vas-
cular clamp-assisted clipping of thick-walled
giant aneurysms. Neurosurgery 2009; 64 (3
Suppl):113-20.
• Niemi T, Armstrong E. Thromboprophylactic
management in the neurosurgical patient
with high risk for both thrombosis and in-
tracranial bleeding. Curr Opin Anaesthesiol.
2010 Oct;23(5):558-63. Review.
• Niemi T, Silvasti-Lundell M, Armstrong E,
Hernesniemi J. The Janus face of thrombo-
prophylaxis in patients with high risk for both
thrombosis and bleeding during intracranial
surgery: report of five exemplary cases. Acta
Neurochir (Wien). 2009 Oct;151(10):1289-
94.
• Randell T, Niemelä M, Kyttä J, Tanskanen
P, Määttänen M, Karatas A, Ishii K, Dashti R,
Shen H, Hernesniemi J. Principles of neu-
roanesthesia in aneurysmal subarachnoid
hemorrhage: The Helsinki experience. Surg
Neurol 2006; 66:382-8.
• Romani R, Lehecka M, Gaal E, Toninelli S,
Celik O, Niemelä M, Porras M, Jääskeläinen
J, Hernesniemi J. Lateral supraorbital
approach applied to olfactory groove menin-
giomas: experience with 66 consecutive
patients. Neurosurgery 2009; 65:39-52.
• Romani R, Kivisaari R, Celik O, Niemelä M,
Perra G, Hernesniemi J. Repair of an alarm-
ing intraoperative intracavernous carotid
artery tear with anastoclips: technical case
report. Neurosurgery 2009; 65:E998-9.
• Romani R, Laakso A, Niemelä M, Lehecka M,
Dashti R, Isarakul P, Celik O, Navratil O,
Lehto H, Kivisaari R, Hernesniemi J. Micro-
surgical principles for anterior circulation
aneurysms. Acta Neurochir Suppl 2010;
107:3-7.
• Romani R, Lehto H, Laakso A, Horcajadas A,
Kivisaari R, von und zu Fraunberg M,
Niemelä M, Rinne J, Hernesniemi J. Micro-
surgery for previously coiled aneurysms:
Experience with 81 patients. Neurosurgery
2010; 68:140-54.
• Romani R, Laakso A, Kangasniemi M, Lehecka
M, Hernesniemi J. Lateral supraorbital

342
APPENDIX 2.
LIST OF ACCOMPANYING VIDEOS
approach applied to anterior clinoidal men-
ingiomas: experience with 73 consecutive
patients. Neurosurgery 2011 Feb 26 (Epub, in
press).
The following 32 videos are included on the
supplementary DVD ”Helsinki Microneurosur-
gery: Basics and Tricks“.
The videos were recorded during microneu-
rosurgical operations by Professor Juha
Hernesniemi from January 2009 to Janu-
ary 2011 at the Department of Neurosurgery,
Helsinki University Central Hospital, Helsinki,
Finland. Professor Hernesniemi has performed
during this time a total of 810 operations (355
patients with cerebral aneurysms, 50 with cer-
ebral AVMs, 28 other cerebrovascular surger-
ies, 270 with brain tumors, and 107 with other
pathologies).
Approaches
1.1. Lateral supraorbital (LSO) approach
(with audio)
1.2. Lateral supraorbital (LSO) approach
(aneurysmal SAH)
1.3. Approach to the lamina terminalis
(aneurysmal SAH)
2. Pterional approach
3. Interhemispheric approach
4. Subtemporal approach
5. Retrosigmoid approach
6. Lateral approach to foramen magnum
7. Presigmoid approach
8. Supracerebellar infratentorial approach -
sitting position
9. Approach to the fourth ventricle and
foramen magnum region - sitting position

Techniques and strategies for
different pathologies
1. Aneurysms
1.1. Anterior circulation
• ACoA aneurysm
• Distal ACA aneurysm
• ICA-PCoA aneurysm
• MCA bifurcation aneurysm
1.2. Posterior circulation
• BA bifurcation aneurysm
• BA-SCA aneurysm
• VA-PICA aneurysm
(All are unruptured small aneurysms,
unless indicated otherwise)
2. AVM‘s
• Frontal-parasagittal AVM
• Parietal AVM
3. Cavernomas
• Cerebellar cavernoma
4. Meningiomas
• Anterior fossa - Olfactory groove
meningioma
• Convexity meningioma
• Falx meningioma
• Posterior fossa - Lateral petrosal
meningioma
• Skull base - Suprasellar meningioma
5. Gliomas
• High-grade glioma
• Low-grade glioma
6. Tumors of the third ventricle
• Colloid cyst of the third ventricle
7. Pineal region lesions
• Pineal cyst
8. Tumors of the fourth ventricle
• Medulloblastoma of the fourth
ventricle
9. Spinal intradural tumors
• Neurinoma L1-2
343

The Helsinki Live Demonstration Course
in Operative Microneurosurgery
Every year the first week in June
Horizons of Knowledge
Competence to master the future.
The Aesculap Academy enjoys a world-wide reputation for medical training
of physicians, senior nursing staff and staff in OR, anesthesia, ward and
hospital management. The CME accredited courses consist of hands-on
workshop, management seminars and international symposia. For that the
Aesculap Academy was given the Frost & Sullivan award as ‚Global Medical
Professional Education Institution of the Year‘ three time in succession.
The Aesculap Academy courses are of premium quality and accredited by
the respective medical societies and international medical associations.
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