Authors :
Presenting Author: Martin Merenzon, MD – Yale New Haven Hospital
Lawrence Hirsch, MD – Professor of Neurology, Neurology, Yale New Haven Hospital; Dennis Spencer, MD – Professor Emeritus and Senior Research Scientist, Neurosurgery, Yale University; Eyiyemisi Damisah, MD – Assistant Profesor, Neurosurgery, Yale University
Rationale: Medically refractory epilepsy often requires resection of the epileptogenic zone (EZ) for effective treatment. However, when the EZ is in eloquent cortex (EC), achieving complete and safe resection becomes intricate. Responsive neurostimulation (RNS) has emerged as a viable option, though it offers seizure reduction rather than complete freedom. We aim to assess the safety and outcomes of a combined approach involving resection and RNS for EC refractory epilepsy.
Methods: Six consecutive patients were treated between 2020 and 2022 for unilateral medically refractory focal epilepsy with EZ and/or spreading areas located in EC. A combination of resection and RNS was employed. A thorough preoperative assessment was conducted.
Results: Patient ages ranged from 21 to 54 years (three females) with epilepsy duration of 6.4 to 36.7 years. Robotic-guided depth electrodes, grids and strips were used to locate the EZ.
In Case 1, the EZ encompassed the primary motor face cortex, extending to the right supplementary motor area (SMA), paracentral and superior parietal lobule. Case 2's EZ resided in the left primary motor hand cortex, SMA, and primary sensory foot cortex (regional pattern). Patient 3's EZ was in the primary visual cortex (cuneus), spreading to the lingual and superior occipital gyrus (SOG) and superior parietal lobule, presenting with two post-epileptic cardiac arrests. Case 4's EZ was within the left posterior superior temporal gyrus, extending to the inferior frontal gyrus, superior and middle temporal gyrus. Case 5 displayed two left EZs: Temporal Pole and Pes Hippocampus, with spread to the Insula and superior/middle temporal gyrus. In Case 6, the EZ was in the central lobule. For central lobe EZ patients, asleep surgical mapping was utilized. In Case 1, the resection targeted the primary motor face cortex, and RNS strips covered the spreading zones. Case 2 involved SMA resection, with RNS strips positioned on the central lobe. For Case 6, part of the postcentral gyrus was resected, and RNS strips were placed in the motor hand/foot area. Case 3's resection focused on the cuneus and SOG, with RNS placement in the lingual gyrus and superior parietal lobule. Transient mild SMA syndrome was observed postoperatively in Cases 1 and 2, while Case 6 had transient arm/foot numbness. Case 3 exhibited a permanent, non-disabling, left quadrantanopia post-surgery. Case 4 experienced transient aphasia post-temporal pole resection, with RNS placement in superior/middle temporal gyrus. Case 5 underwent anterior medial temporal lobectomy, modulating the insula and posterolateral temporal lobe. Importantly, Cases 1, 4, and 5 achieved seizure freedom (Engel IA); Cases 2 and 6 were mostly seizure-free (Engel IIA), with rare disabling seizures after the 2+ years follow-up. Case 3 had non-disabling seizures (Engel IB) at the 8 months follow-up.Conclusions: The combined approach presents a promising alternative to standalone resections for EC medically refractory epilepsy. This method contributes to preserving function while improving seizure outcomes.
Funding: NA