Awake Craniotomy in Epilepsy Surgery: A Case Series and Proposal for Three Different Scenarios

Abstract

Objective: Awake craniotomy (AWC) allows intraoperative evaluation of functions involving the cortical surface and subcortical fibers. In epilepsy surgery, indications for and the role of AWC have not been established because evaluation with intracranial electrodes is considered the gold standard. We report herein our case series of patients who underwent AWC in epilepsy surgery and propose the scenarios for and roles of AWC. Methods: Patients who underwent AWC in epilepsy surgery at our institutions between 2014 and 2023 were included. Information about age, sex, etiology, location of epileptogenicity, seizure type, use of intracranial electrode placement, surgical complications, neurological deficits, additional surgery, and seizure outcomes was reviewed. Following a diagnostic and treatment flow for epilepsy surgery, we clarified three different scenarios and roles for AWC. Results: Ten patients underwent AWC. Three patients underwent AWC after non-invasive evaluations. Two patients underwent AWC after intracranial evaluation with stereotactic electroencephalography (SEEG). Five patients underwent AWC after intracranial evaluation with subdural grid electrodes (SDG). Among these, two patients were initially evaluated with SEEG and with SDG thereafter. One patient reported slight numbness in the hand, and one patient showed slight cognitive decline. Seizure outcomes according to the Engel outcome scale were class 1A in three patients, IIA in two patients, IIIA in four patients, and IVA in one patient. Conclusions: AWC can be used for purposes of epilepsy surgery in different situations, either immediately after non-invasive studies or as an additional invasive step after invasive monitoring with either SEEG or SDG. The application of AWC should be individualized according to each patient’s specific characteristics.

Keywords

• awake craniotomy
• epilepsy surgery
• indication
• strategy
• general anesthesia