The role of stereoelectroencephalography (SEEG) in repeat epilepsy surgery

Abstract

Objective To explore the role of stereoelectroencephalography(SEEG) in evaluation of epilepsy resurgery. Methods Thirty-nine patients with a surgical failure and clinical seizures in the SEEG monitoring were retrospectively included in this study at Department of Founctional Neurosurgery, Sanbo Brain Hospital, Capital Medical University from August 2011 to January 2018. The evaluation results from application of SEEG and efficacy of resurgery were analyzed. Results The seizure onset zone (SOZ) located in the neighboring areas around the initial surgical region in 14 (36%) patients, and in the non-neighboring areas in 25(64%) patients, among whom SOZ located in the same side as the initial surgical region but far apart from it in 21 patients(54%). High frequency discharges were the most common SEEG pattern of seizure onset with a total of 19 cases (49%), followed by the low voltage fast activities with a total of 8 cases (21%). The seizure onset from single brain region was shown in 32 cases (82%), and that from multi brain regions was shown in 7 cases (18%). After SEEG evaluation, 4 patients did not undergo surgical treatment, and the remaining 35 cases were followed by re-surgery. There were 33 cases followed up more than 12 (12-51) months in total, among whom 16 cases (49%) classified as Engel I, 3 cases (9%) Engel Ⅱ, 2 cases (6%) Engel Ⅲ, and 12 cases (36%) Engel Ⅳ. Nineteen cases undergone anterior temporal lobectomy in the first surgery, and 17 cases were re-operated after SEEG evaluation, among whom 16 cases were followed up more than 12 month and 8 cases were classified as Engle Ⅰ. Conclusions Nearly half of patients achieved seizure freedom after repeated surgery by SEEG evaluation. The success rate of epilepsy resurgery is mainly related to the accuracy of localization of epileptogenic zone. Key words: Epilepsy; Stereoelectroencephalography; Reoperation