Surgical outcome of epilepsy caused by cortical dysplasia

Purpose: Cortical dysplasia (CD) is the second most common pathologic entity in surgically treated epilepsy. To delineate its surgical outcome and prognostic factors, we performed a retrospective analysis of patients operated on at a single institute. Methods: Between September 1994 and December 2000, 128 cases with CD were operated on at our institute. The male/ female ratio was 85: 43, and the mean age was 27 years (SD, 7.6 years). The mean postoperative follow- up period was 26.9 months (SD, 12.0 months). Seizure outcome and severity of CD were classified according to Engel's and Mischel's classifications, respectively. Severity of CD was mild in 69, moderate in 21, and severe in 38. Lobar distribution was temporal in 54, frontal in 48, and others in 26. Cortical resection, lobectomy, or hemispherectomy was done in all patients. Univariate analysis was done followed by multivariate analysis by using computerized statistical software. Results: Postoperative seizure outcome was Engel class I in 58 (45.3%), II in 17 (13.3%), III in 16 (12.5%), and IV in 37 (28.9%). Transient postoperative complications occurred in 14 (10.9%) patients without mortality or permanent neurologic impairment. Multivariate analysis revealed severity of CD and frontal lobe resection as independent prognostic factors for worse outcome (p = 0.001 and 0.003, respectively). Conclusions: Epilepsy surgery for CD achieved 45.3% seizure- free rate with 10.9% transient postoperative complications in our institute. Worse postoperative seizure outcome was observed in cases with mild CD and frontal lobe resection.