1. Awake Craniotomy: Role in Neurosurgical Management Christine Stewart University of Minnesota, MS4

2. Outline Case R.P. Classic indications and exclusion criteria Factors to consider when defining eloquent areas Recommendations

3. R.P. 42 RHM w/ long history of seizures recently changed in character, worsening H/A over past several months. Wife notes increasing apathy, slow processing Difficulty with word-finding, long-term memory, mood-swings Other PMHx: – Cyclist v. car 1983: LOC 1-2 minutes, right frontal frx w/ CSF leak  meningitis – 1 st seizure 1985 GTC w/ auras – Another episode of meningitis 1985  intracranial abscess R. frontal lobe  R. frontal craniotomy – Imaging from 2002-2008 show a hypodensity in the left frontal lobe which was interpreted as encephalomalcia given hx – Hypothyroidism Medications: – Lamictal 400 mg – Vimpat 200 mg BID – Levothyroxine

4. Imaging

5. Classic Indications for Awake Craniotomy 1 Surgery in ‘eloquent’ brain – Near motor strip – Speech/language centers – Thalamus Removal of brainstem tumors Search for a focus of seizure activity

6. Exclusion Criteria 2,3, 4 Inability to cooperate: dysphasia, language barrier, emotional labiality, cognitive impairment Low occipital tumors Tumors with significant dural attachment Patients < 11 years old 5

7. Eloquent areas and factors to consider: Anatomical variability 6 – ICBM 452 atlas “Average” brain – Factors: sex, age, handedness, neurological and psychiatric disease

8. Eloquent areas and factors to consider: Functional variability 6,7,8 – Even areas with the same anatomical landmarks may not harbor the same underlying function Motor cortex variability: – “Hand knob” of pre-central gyrus can represent primary motor cortex or premotor cortex – Stimulation in pre-central cortex can result in sensory and motor responses or motor responses in > 1 motor group – Primary motor area may extend > 20 mm anterior to the central sulcus

9. Eloquent areas and factors to consider: Functional variability Variability in language cortices 6 – > 4cm of variability in intraoperative speech arrest J Neurosurg 71:316–326, 1989.

10. Eloquent areas and factors to consider: Effect of space-occupying lesions – Unusual functional acquisition: congenital lesions (AVMs)  higher incidence right v. left sided language 6 – Reorganization: LGG (low grade gliomas)/other adult neurological injury  reorganization of speech center s.t more frontal speech centers in pt vs. controls 10 – Extent likely depends on time-course of injury 9 – Illustratively, these patients rarely present with neurodeficits 9

11. Variability in Mapping Functional Localization 2,6 Either measuring electrophysiological signals or perfusion Electrocortical stimulation mapping (ESM) identifies essential and involved areas – Other methods seem to be more sensitive to map all involved areas, but do not identify which are essential If essential area is identified: – Appropriate resection margins have not been recommended

12. Effects of Mapping 4 % of all patients% w/ post-op neurodeficits % w/ deficits who were previously intact + Mapping22.5%20.9%4.4% - Mapping77.5%13.5%1.8%

13. When considering awake craniotomy: Outcomes – No prospective randomized control trial has been done directly comparing awake v. GA 3 Patient experience – Awake procedures are well-tolerated 11 Overall satisfaction rated: 71-93% Significant pain identified: 8-29% All of this literature asks post-op and relies on recall – Non-language deficits are noted after surgeries done under GA 2 Visual, spatial perceptions, cognitive and behavioral disorders noted as more individuals do neuropsychological testing. Cost 4 – Reduces operating time Dependent on experience level – Reduces post-op ICU stay – Reduces total hospital stay Median LOS: 1 day

14. Recommendations No ‘gold standards’ for pre-operative mapping b/c no outcomes-correlated evidence – fMRI at minimum – DTI may help define white matter tracts in and around the lesion – Others: MEG, PET Intra-operative monitoring should be mandatory – only technique with validated outcomes measures

15. References 1 Greenberg, M. Handbook of Neurosurgery. 7 th edition. 2 Duffau, H. Awake surgery for non-language mapping. Neurosurgery. 66:523-529, 2010. 3 Kirsch, B. and Bernstein, M. Ethical challenges with awake craniotomy for tumor. Can. J. Neurol Sci 39: 78-82, 2012. 4 Serletis, D. and Bernstein, M. Prospective study of awake craniotomy used routinely and non- selectively for supratentorial tumors. J Neurosurgery. 107:1-6, 2007. 5 Berger, MS. The impact of technical adjuncts in surgical management of cerebral low grade gliomas of childhood. J. of neuro-oncology. 1996; 28:129-155. 6 Pourtrain, N. and Bookheimer, S. Reliability of anatomy as a predictor of eloquence: a review. Neurosurg Focus 28:E3, 2010. 7 Shinoura N, Suzuki Y, Yamada R, Tabei Y, Saito K, Yagi K:Precentral knob corresponds to the primary motor and premotor area. Can J Neurol Sci 36:227–233, 2009 8 Uematsu S, Lesser R, Fisher RS, et al: Motor and sensory cortex in humans: topography studied with chronic subdural stimulation. Neurosurgery 31:59–72, 1992 9 Desmurget M, Bonnetblanc F, Duffau H: Contrasting acute and slow-growing lesions: a new door to brain plasticity. Brain 130:898–914, 2007 10 Lucas TH II, Drane DL, Dodrill CB, Ojemann GA: Language reorganization in aphasics: an electrical stimulation mapping investigation. Neurosurgery 63:487–497, 2008 11 Manchella, S. et al. The experience of patients undergoing awake craniotomy for excision of intracranial masses: expectations, recall, satisfaction and functional outcome. British Journal of Neurosurgery. June 2011. 25(3): 391-400.