Abstracts

Rationale: Introduction:The surgical management of medically-refractory epilepsy involves a staged evaluation to define the epileptogenic focus. In patients with tuberous sclerosis complex (TSC), by the multifocal nature of the disease, there can be multiple epileptogenic tubers. Often noninvasive (stage 1) evaluation of TSC patients is non-localizing or lateralizing as the surface EEG may not correlate with suspected clinical seizure activity. In this case series, we identify four patients with tuberous sclerosis whose stage 1 presurgical evaluations were inconclusive, but whom were found to have active epileptogenic foci on invasive stereo EEG monitoring.  Methods: Case Series:Four children (age 2-6yo, two male/two female) with tuberous sclerosis were treated at the Comprehensive Pediatric Epilepsy Program at Children’s National Health System in Washington, DC. Stage 1 (noninvasive) and stage 2 (invasive stereoEEG) evaluations are described in the table. All patients had scattered bilateral cortical tubers on 3Tesla MRI. Surface EEG and/or MEG were nonlocalizing/nonlateralizing in all cases, thus necessitating invasive monitoring. StereoEEG identified seizure onset zones from unilateral tubers in 3 cases, and bifrontal tubers in 1 case. Two patients were managed with minimally invasive laser ablation of tubers; the other two with open resection. 3/4 patients achieved Engel I outcome; 1 patient had Engel II outcome. There were no surgical complications. Results: Discussion:TSC is a neurocutaneous disorder often complicated by pharmaco-resistant epilepsy. In the management of these patients, when surface EEG does not localize the seizure onset zone, minimally invasive monitoring with sEEG to include depth electrodes in multiple tubers may be part of the epilepsy surgical evaluation. We demonstrate the use of stereoEEG to clearly identify epileptogenic tubers in four patients whose stage 1 presurgical evaluation were unrevealing. All patients had successful ablation or removal of the epileptogenic tissue. Engel I outcome was achieved in 3/4 patients without complication.  Conclusions: Conclusion:In TSC patients with medically refractory epilepsy who have unrevealing stage 1 evaluations, minimally invasive stereo EEG may be an effective method to localize deep seizure foci and guide surgical intervention to achieve seizure-freedom.  Funding: No funding