Awake Craniotomy with Cortical and Subcortical Speech Mapping for Supramarginal Cavernoma Resection

Abstract Awake craniotomy allows mapping of eloquent brain regions and monitoring neurocognitive functioning intraoperatively to maximize extent of resection and minimize cognitive morbidity.1,2 During resection of cavernous malformations in eloquent areas, intraoperative cognitive monitoring can also allow for safer maximal excision of the hemosiderin ring which is correlated with improved seizure-free outcome.3,4 We present the case of a 33-year-old right handed male with a new onset seizures who presented to local ED after experiencing visual hallucinations before losing consciousness. CT scan of the head revealed a calcified lesion in the left temporal/parietal area. Presurgical work-up revealed left hemispheric language dominance and language activation within the overlying supramarginal gyrus representing phonologic working memory on fMRI.5 Diffusion tensor imaging identified the arcuate fasciculus and lateral portion of the superior longitudinal fasciculus (SLF-III) to be intimately associated with the deep margin of the lesion.6 After consent was obtained, we performed an awake craniotomy and resection of the lesion through a transulcal approach, with eloquent cortical mapping using a novel high-density circular grid7,8, as well as subcortical stimulation/mapping and continuous intraoperative cognitive monitoring using multiple language paradigms; the patient was baselined on these paradigms preoperatively. Several phonological/paraphasic errors were made during resection of the hemosiderin ring, likely related to mechanical manipulation. The patient was discharged to home on post-operative day four with outpatient speech therapy for speech hesitancy. At 1-week postoperative testing, language skills were considered within normal limits.