Abstracts

RATIONALE: To investigate the effect of the timing of epilepsy surgery on seizure outcome in patients with intractable partial epilepsy undergoing a focal cortical resection.
METHODS: We performed a retrospective analysis of seizure outcome in 526 consecutive patients who were surgically treated for medically refractory partial seizures at Mayo Clinic, Rochester, MN, between 1988 and 1996. 479 patients had temporal lobe epilepsy. The mean age at surgery was 32 years (range, 3-69). The mean age of seizure onset was 13 years (range, 0-65). A modified Engel classification was used for seizure outcome.
RESULTS: The duration of epilepsy prior to surgery and the seizure outcome were available in 520 patients. The mean duration of epilepsy was 18.6 years (range, 0-56). The association between operative outcome and duration of epilepsy was not significant (Spearman[ssquote]s Rho, p= 0.417). The patients were separated into 3 groups based on the timing of the operative procedure: Group I= duration of epilepsy less than or equal to 5 years (n=88), Group II= duration of epilepsy 6-34 years (n=369), and Group III= duration of epilepsy greater than or equal to 35 years (n=63). The outcome for the 3 groups was not significantly different (Kruskal-Wallis test, p= 0.871). The outcome in patients who underwent early surgery (Group I) and late surgery (Group III) were subsequently compared. The timing of surgery in these patients did not effect the outcome classification (Wilcoxon rank sum, p= 0.639). Finally, the associations between the age of seizure onset and outcome (Pearson correlation coefficient, r= 0.01), and the age at surgery and outcome (Pearson correlation coefficient, r= -0.05) were also not significant.
CONCLUSIONS: Early surgery for epilepsy has potential putative beneficial effects on quality of life. The present series, however, failed to demonstrate that early surgery was more effective than later surgery in reducing seizure tendency.
[Supported by: Mayo Foundation.]