Improved outcomes with earlier surgery for intractable frontal lobe epilepsy

Abstract

To explore the prognostic implications of epilepsy duration and age at surgery for seizure outcomes after frontal lobe epilepsy (FLE) surgery. We reviewed 158 patients who underwent FLE surgery from 1995 to 2010. The primary outcome was seizure freedom at last follow-up (Engel class IA). Analyses employed Cox proportional and multiphase hazard modeling. The mean age at surgery was 20.4 years, and mean epilepsy duration was 12.0 years. The estimated chance of seizure freedom was 66% (95% confidence interval [CI] = 62-68) at 1 postoperative year, 52% (95% CI = 48-56) at 2 years, and 44% (95% CI = 39-49) at 5 years and beyond. Seventy-five percent of recurrences occurred within 6 postoperative months. Both younger age at surgery (<18 years) and shorter epilepsy duration (<5 years) correlated with better seizure outcomes on univariate analysis, but only epilepsy duration remained statistically significant after multivariate modeling. Independent poor prognostic indicators included left-sided resections and acute postoperative seizures (APOSs; whole model log-rank test p < 0.0001). APOSs were particularly predictive of early epilepsy recurrence, starting within 6 postoperative months (adjusted risk ratio [RR] = 4.42, p < 0.0001), whereas long epilepsy duration correlated with late recurrences (RR = 6.25, p < 0.0001). Worse outcomes were seen with longer epilepsy duration for duration cutoffs of 2, 5, and 10 years independently for adults and children, although statistical significance was only achieved in children (66% seizure free at 5 postoperative years if operated on within 5 years of epilepsy onset vs 31% if later; p = 0.01). Early resection may improve seizure outcomes of FLE surgery, particularly in children.