Introduction: To evaluate the feasibility of extending extraoperative stereoelectroencephalography (SEEG) monitoring into the intraoperative setting in cases of medically intractable rolandic epilepsy (RE) to better guide tissue resection based on real time monitoring.

Methods: We retrospectively studied the surgical technique, extent of resection, pathology and outcomes of patients with intractable RE, as suspected on preoperative evaluation and confirmed on SEEG monitoring.

Results: Four patients were identified as having intractable RE based on analysis of preoperative SEEG. Magnetic resonance imaging was nonlesional in all four. All patients underwent preoperative imaging with stereo CT to determine the location of electrode contacts and their related anatomy for neuronavigation purposes. CT was fused to pre-SEEG MRI. Intraoperative SEEG was performed to determine the exact location of the contacts showing epileptogenic activity, and once localized, tissue resection around these was performed until disappearance of spikes, while avoiding motor and sensory areas. Interestingly, all spikes coming from the rolandic areas disappeared after resection of peripheral active tissues involving the SMA, cingulate and pre-motor areas in two patients. In one patient, hand sensory area was resected without motor deficit. In another patient, spikes originating in the paracentral lobule region disappeared after resection, with only mild post-operative foot drop. Pathology analysis showed focal cortical dysplasia type IIA with nodular heterotopia in one patient and a possible vacular malformation in another.

Conclusions: The present study shows the feasibility and safety of extending SEEG evaluation into the intraoperative setting in order to better guide the surgeon for a more accurately tailored resection of tissue in rolandic epilepsy.

Patient Care: Our research has the potential to render better outcomes based on further, intraoperative real time localization of epileptogenic focus and its full resection while avoiding injury to eloquent areas.

Learning Objectives: By the conclusion of this session, participant should be able to: 1. understand the feasibility of expanding SEEG into the intraoperative setting. 2. To understand the importance of real time intraoperative data acquisition in order to better tailor epileptogenic zone resection.

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