Cortical electrocorticography monitoring in surgical management of secondary epilepsy

Objective To investigate the therapeutic effect of surgical management on patients with secondary epilepsy under the monitoring of cortical electrocorticography (ECoG). Methods Eighty-four patients with secondary epilepsy, admitted to our hospital from September 2004 to January 2008, were chosen; intraoperative ECoG monitoring was performed to locate the epileptic foci before the resection of the primary lesion. After the resection of primary lesion, resection of epileptic foci, enlarged resection of epileptic foci, cortical thermocoagulation, anterior temporal lobectomy,amygdalohippocampectomy and anterior callosotomy were performed, respectively, in different patients according to the clinical manifestations of seizures, and the locations of lesions and epileptic waveform discharges detected by intraoperative ECoG monitoring. Results The epileptic waveform discharges in 84 patients were noted before the resection of primary lesion. The epileptic waves were found in 80patients at the peripheral areas of the primary nidus under immediately postoperative ECoG monitoring,with a relevance ratio reaching 95.24%; after the resection of residual cortical zone with epileptic wave discharges, epileptic wave disappeared on immediately postoperative ECoG in 13 patients whose lesion located in nonfunctional area; normal signals were noted in 60 of the 67 patients performed cortical thermocoagulation whose cortical zone with epileptic wave discharges were located or neighbored in functional area, and good outcomes under the immediately postoperative ECoG monitoring were noted in the other 7 patients performed thermocoagulation combined with anterior callosotomy and/or amygdalohippocampectomy. The follow-up studies for 10 months to 4 years showed that grade Ⅰ in 56patients (66.67%), grade Ⅱ in 21 (25.00%), grade Ⅲ in 4 (4.76%) and grade Ⅳ in 3 (3.57%) according to the Engle standard of curative effect were achieved; the total effective rate was 96. 42%. Conclusion ECoG monitoring can significantly improve the efficiency of surgical management of secondary epilepsy. Key words: Epilepsy;  Cortical electrocorticography;  Surgical management