Stereo-EEG Seizure Localization in Patients with Medically Intractable Focal Epilepsy Associated with Schizencephaly (2505)

Objective: To demonstrate that stereo-electroencephalography (SEEG) may successfully localize the epileptogenic zone in patients who have focal epilepsy related to schizencephaly. Background: The optimal treatment for the medically refractory focal epilepsy in patients with schizencephaly is epilepsy surgery, however there is limited data in the role of SEEG evaluation in localization of the epileptogenic zone in this population. Design/Methods: Among 160 patients with medically intractable focal epilepsy who underwent invasive pre-surgical evaluation with stereo-electrodes in our institution during five years, 3 had schizencephaly. We describe the stereo-EEG evaluation results in these patients. Results: All patients had stereoelectrodes placement covering the cortex around the schizencephaly cleft, and bilateral sampling of mesial temporal structures. Patient 1 had the ictal onset of her clinical seizures localized near the schizencephalic cleft. Currently, she is 14 months seizure free after the resection of the epileptogenic focus. Patient 2 had the ictal onset of his clinical seizures localized to the hippocampus ipsilateral to the schizencephalic lesion. He also had two types of sub-clinical seizures: type 1 started from the hippocampus ipsilateral to the schizencephaly, and type 2 started from the schizencephaly. Currently, he is five months seizure-free after an anterior temporal lobectomy including mesial temporal structures ipsilateral to the schizencephaly. Patient 3 did not have spontaneous clinical seizures during 30 days of SEEG monitoring. She had sub-clinical seizures originating from the stereoelectrodes contacts within her schizencephalic lesion. Extraoperative electrical cortical stimulation triggered her typical seizures from these same stereoelectrodes contacts within schizencephaly. She has not had post-SEEG surgery yet. Conclusions: Our center experience demonstrates that extraoperative EEG monitoring with stereo-electrodes is a reliable and safe method of intracranial EEG evaluation of patients with medically intractable focal epilepsy related to schizencephaly. Disclosure: Dr. Podkorytova has nothing to disclose. Dr. Lega has nothing to disclose. Dr. Hays has nothing to disclose. Dr. Agostini has nothing to disclose. Dr. Alick has nothing to disclose. Dr. Das has nothing to disclose. Dr. Dave has nothing to disclose. Dr. Dieppa has nothing to disclose. Dr. Ding has nothing to disclose. Dr. Doyle has nothing to disclose. Dr. Harvey has nothing to disclose. Dr. Zepeda Garcia has nothing to disclose. Dr. Perven has nothing to disclose.