Abstracts

RATIONALE: Cortical dysplasia is the second most common pathological entity in surgically treated epilepsy, surpassed only by hippocampal sclerosis. However, its surgical outcome and prognostic factors are not well established compared with hippocampal sclerosis. To make a better understanding, we performed detailed analysis of surgical cases with cortical dysplasia operated upon at a single institute. METHODS: Between 1994 and 1998, 120 patients with cortical dysplasia were operated upon at the Seoul National University Comprehensive Epilepsy Surgery Program. Male-female ratio was 81:39, and mean age was 27 years (SD, 7.6). Mean postoperative follow-up period was 26.9 months (SD, 12.0). Invasive study was done in 70 patients. Seizure outcome was classified according to Engel's Classification, and classification of cortical dysplasia followed Mischel's. Severity of cortical dysplasia was mild (99), moderate (12), or severe (9). Forty-eight patients had also hippocampal sclerosis, among whom moderate or severe cortical dysplasia was found in 6 patients. Topographic distribution was temporal (67), frontal (26), multilobar (13), occipital (8), parietal (4), and hemispheric (2). Cortical resection, lobectomy or hemispherectomy was done in all patients. Univariate analysis was done for age, sex, pathological severity, and topographic distribution. RESULTS: Postoperative seizure outcome was Engel Class I (75 patients, 62.5%), II (10, 8.3%), III (17, 14.2%), and IV (18, 15%). Four patients in Engel Class IV achieved more than 75% seizure reduction. Postoperative complications occurred in 10 patients (8.3%). Permanent neurological deficit occurred in 2 (1.7%). Severity of cortical dysplasia and sex had no significant relationship with seizure outcome. Frontal lobe epilepsy had worse seizure outcome than temporal lobe epilepsy (p<0.036). Early seizure onset was associated with worse postoperative seizure outcome (p<0.026). CONCLUSIONS: Epilepsy surgery for cortical dysplasia achieved 62.5% seizure-free outcome with 1.7% morbidity in single institute. Postoperative worse seizure outcome was observed in patients with frontal lobe epilepsy and early seizure onset.