Long-term seizure outcome in reoperation after failure of epilepsy surgery

OBJECTIVE: Treatment of patients who fail epilepsy surgery is problematic. Selected patients may be candidates for further surgery, potentially leading to a significant decrease in the frequency and severity of seizures. We present our long-term outcome series of highly investigated patients who failed resective epilepsy surgery and subsequently underwent reoperative resective procedures. METHODS: We performed a retrospective consecutive analysis of patients who underwent reoperative procedures because of medically intractable epilepsy at our institution from 1990 to 2001. Seventy patients underwent reoperative epilepsy surgery, with 57 patients having a minimum follow-up period of 2 years. We assessed the relationship between seizure outcome and categorical variables using chi(2) and Fisher's exact tests, and the relationship between outcome and continuous variables using a Wilcoxon rank-sum test. Statistical significance was set at a P value of 0.05. RESULTS: Of the 57 patients (29 male and 28 female patients), the age of seizure onset ranged from 3 months to 39 years (mean, 10.7 +/- 10.3 yr; median, 7 yr). The mean age at reoperation was 24.7 +/- 12 years (range, 4-50 yr). The interval between first and second resection was 7 days to 16 years. The follow-up period ranged from 24 to 228 months (mean, 128 mo; mode, 132 mo). Seizure outcome was classified according to Engel's classification. Fifty-two percent of the patients had a favorable outcome (38.6% were Class I and 14.0% were Class II). Patients with tumors as their initial pathology had better outcome compared with patients with focal cortical dysplasia and mesial temporal sclerosis (P < 0.05). CONCLUSION: Reoperation should be considered in selected patients failing epilepsy resective surgery because approximately 50% of patients may have benefit. Patients with cortical dysplasia and mesial temporal sclerosis are less likely to improve after reoperation.