Intraoperative Monitoring for Brain and Spinal Cord Tumors
Download as PPTX, PDF6 likes788 views
Intraoperative monitoring (IOM) during brain and spinal surgeries aims to prevent new or worsened neurological deficits. While IOM is not based on class I evidence, controlled studies would be unethical given its effectiveness in predicting injuries. Studies show IOM reduces postoperative deficits compared to no monitoring. For glioma resections, IOM-guided resection allows safer maximal removal in eloquent areas, improving survival and quality of life. Awake craniotomy with IOM results in fewer deficits than general anesthesia. While false negatives and cost are challenges, IOM avoidance risks greater deficits and rehabilitation costs. IOM should be used for brain and spinal tumor resections when near critical structures.
![22.4
9.6
2.4 1.6
0
5
10
15
20
25
1 Week 1 Month 3 Month 6 Month
% Worsening of speech or new speech deficit
[total n=250]
GTR 59.6% [65.5% for grade III, 69.0% for grade IV, 51.6% for grade I and II]](https://image.slidesharecdn.com/iomisnocon-170624113738/85/Intraoperative-Monitoring-for-Brain-and-Spinal-Cord-Tumors-12-320.jpg)
Intraoperative Monitoring for Brain and Spinal Cord Tumors
- 1. Critical Appraisal of Monitoring in Neuro-oncology – What is the Evidence? Dhaval Shukla Professor of Neurosurgery NIMHANS, Bangalore
- 3. Goal of Intraoperative Monitoring (IOM) Immediate postoperative neurologic deficit • New (or worsened) neurologic deficit is recognized immediately postoperatively, typically within a few hours of recovering from surgical anesthesia Permanent or persisting neurologic deficit • New (or worsened) neurologic deficit persists beyond the immediate postoperative period and is present at the time of hospital discharge or last clinical follow-up
- 4. Correlation of Neural Injury with IOM Signals • A signal change predicts a neurologic deficit. • The signal change occurs during the surgery, in time for corrective action to be taken. • A permanent injury can be avoided if the signal recovers with the corrective action. • There should not be any false negatives.
- 5. IOM: Is it evidence-based? • There is little discussion about the fact that IOM is not based on class I evidence • Likelihood of preventing a neurological deficit using IOM is so high for certain pathologies that a controlled study where patients are randomly assigned to a control group or a monitored group would be unethical and unacceptable to patient and surgeon alike • Incidence of severe and permanent neurological complications for standard neurosurgical procedures is quite low • The benefit of IOM will continue to be based on good clinical outcomes, historical control studies, and cost– benefit evaluations. Sala. Child’s Nerv System 2010.
- 6. AAN Evidence-based Guideline Update: Intraoperative Spinal Monitoring • In the class I studies, 16% to 40% of the IOM patients with EP changes developed postoperative-onset paraparesis, paraplegia, or quadriplegia. • IOM is established as effective to predict an increased risk of the adverse outcomes of paraparesis, paraplegia, and quadriplegia in spinal surgery (4 Class I and 7 Class II studies). RECOMMENDATION • Surgeons and other members of the operating team should be alerted to the increased risk of severe adverse neurologic outcomes in patients with important IOM changes (Level A). Nuwer, et al. J Clin Neurophysiol 2012
- 7. Intramedullary Spinal Cord Tumors Sala, et al. Neurosurgery 2006.
- 8. IOM for Brain Tumors (Gliomas) • Maximum Safe Resection • Why Maximum? • Increase in survival • Why Safe? • Development of permanent neurological deficits results in significant decrease in QOL • Neurological impairment may preclude or delay postoperarive adjuvant treatment
- 9. Gliomas: Extent of Resection Parney & Berger. Handbook Clin Neurol 2012.
- 10. Without Mapping (n= 100) • Eloquent areas - 35% • Permanent deficits - 17% • Resection • STR - 37% • PR - 6% With Mapping (n= 122) • Eloquent areas - 62% • Permanent deficits - 6.5% • Resection • STR – 50.8% • PR - 25.4%
- 11. Late severe neurologic deficits were observed in 3.4% (95% CI, 2.3% to 4.8%) of patients after resections with ISM, and in 8.2% (95% CI, 5.7% to 11.4%) of patients after resections without ISM GTR were 75% (95% CI, 66% to 82%) with ISM and 58% (95% CI, 48% to 69%) without ISM Stimulation mapping is important in patients with more complex gliomas to determine where to end a partial resection to avoid permanent neurologic deficits. ISM is valuable in optimizing resective surgery by minimizing the rate of late severe deficits and maximizing the extent of resection, particularly for gliomas involving eloquent brain regions.
- 12. 22.4 9.6 2.4 1.6 0 5 10 15 20 25 1 Week 1 Month 3 Month 6 Month % Worsening of speech or new speech deficit [total n=250] GTR 59.6% [65.5% for grade III, 69.0% for grade IV, 51.6% for grade I and II]
- 13. Awake Craniotomy Awake Craniotomy n = 411 • Hospital stay (4 d, n=110) • GTR (41%, n=321) • Postoperative deficits (7%, n=411) • Surgery time (165 min, n=324) General Anesthesia n = 540 • Hospital stay (9 d, n=11) • GTR (44%, n=444) • Postoperative deficits (23%, n=520) • Surgery time (168 min, n=477) Brown, et al. J Neurosurg Anesthesiol 2013.
- 14. Barriers with adoption of IOM • False-negative frequency for MEP • Methods to correct limitations still needs to be developed • Professional clinical neurophysiologist supervisor experienced with IOM is required • IOM conducted by technicians alone or by an automated device is not advisable
- 15. Cost–benefits of IOM • Equipment and disposables • Training and remuneration for the monitoring personnel Vs • Avoidance of neurological complications • Rehabilitation costs • Economic compensation • Human suffering • The true limitation is lack of human resources Sala. Child’s Nerv System 2010.
- 16. Exceptions to Standard Use of IOM • Patients in whom a radiologically complete resection can be achieved at a distance from critical brain structures do not benefit from IOM • When the expected increase in survival from an aggressive resection approximates rehabilitation time
- 17. Hype cycle of IOM Sala. Child’s Nerv System 2010.
- 18. IOM should be incorporated for resection for brain and spinal cord tumor
Editor's Notes
- #8: The applied motor evoked potential methods seem to improve long- term motor outcome significantly.
- #11: N extension of indications of LGG surgery within eloquent areas N decrease of the risk of sequelae N increase of the quality of tumour resection itself, with an impact on survival.
- #18: 1. Technology trigger: This is the first phase, a breakthrough that occurs when a new product is launched on the market generating interest and attraction. In our setting, this dates back to the implementation of IN techniques in the mid- and late-1990s. 2. Peak of inflated expectations: This is what happens when overenthusiasm and unrealistic expectations are generated. In this phase, successful applications and failures of a technology occur. We may apply this to the time when too much expectation was placed on SEPs followed by the first false-negative results appearing in the literature. 3. Trough of disillusionment: This is what happens when expectations are not met and technologies become unfashionable. This may correspond to the time, immediately before the advent of MEPs, when the limitations of SEPs became evident but no alternatives were available. A similar disillusionment is experienced even today whenever we expect IN to be more reliable in specificity and sensitivity. 4. Slope of enlightenment: This is the phase of maturity, when in spite of some failures, research continues to grow, identify reliable goals, and extend applications. The advent of intraoperative MEPs represented a real breakthrough in this regard, together with major awareness of the value and limitations of different IN techniques. 5. The plateau of productivity: This corresponds to the phase where the benefits of a technology become widely demonstrated and accepted, leaving behind prejudices. Today, IN is experiencing a plateau of productivity in tertiary care hospitals and academic institutions where it is performed according to both the highest professional level and standards of care. It is hoped that in our patients’ best interest, IN will become available on a larger scale. As neurosurgeons, there is no valid reason to reject the support that IN can provide to us. IN is not aimed at replacing a deep knowledge of neuroanatomy nor can it surrogate a lack of clinical judgment when facing challenging situations in the operating room. However, it does represent one more tool in our hands which we can use “ad hoc” to improve our results and make neurosurgery safer.