Awake Craniotomy Role in Neurosurgical Management Christine Stewart

Awake Craniotomy: Role in Neurosurgical Management Christine Stewart University of Minnesota, MS 4

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

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

Imaging

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

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

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

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

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

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

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

Effects of Mapping 4 % of all patients % w/ post-op neurodeficits % w/ deficits who were previously intact + Mapping 22. 5% 20. 9% 4. 4% - Mapping 77. 5% 13. 5% 1. 8%

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 • Cost 4 • Visual, spatial perceptions, cognitive and behavioral disorders noted as more individuals do neuropsychological testing. – Reduces operating time • Dependent on experience level – Reduces post-op ICU stay – Reduces total hospital stay • Median LOS: 1 day

Recommendations • No ‘gold standards’ for pre-operative mapping b/c no outcomes-correlated evidence – f. MRI 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

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 nonselectively 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: E 3, 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.