"Time is Brain"-How early should surgery be done in drug-resistant TLE?

Objectives: To explore the effect of duration of epilepsy and delay in surgery on seizure outcome in patients operated for drug-resistant temporal lobe epilepsy (TLE).

Materials & methods: A total of 664 consecutive patients who underwent anterior temporal lobectomy (ATL) for TLE from 1995 to 2008 formed the study cohort. We divided them into two, one as seizure-free with or without antiepileptic drugs after ATL as "good outcome" (Engel class I a) and seizures of any type, any time after surgery as "poor outcome." The probability of seizure freedom/seizure recurrence based on the duration of epilepsy was compared using Kaplan-Meier curves, univariate Cox regression survival analysis, and multivariate Cox proportional hazards regression model.

Results: A total of 136 children and 528 adults underwent ATL during this period. Mean duration of epilepsy pre-ATL was 17.1 + 9.4 years. At mean follow-up of 8.5 years, 331 patients (49.8%) had good outcome and 333 (50.2%) had poor outcome. The hazard of seizure recurrence linearly increased with duration of epilepsy pre-ATL, from 1.5 (duration of epilepsy, 5-10 years) to 1.9 (duration of epilepsy, 10-15 years) to 2 (duration of epilepsy over 15 years). In addition, encephalitis as antecedent, bilateral mesial temporal sclerosis in MRI, normal histopathology, and spikes in postoperative EEG at 3 months and 1 year predicted poor seizure outcome.

Conclusions: "Epilepsy duration" independently predicted both short- and long-term seizure outcome after surgery in TLE. "Lost years" translate into poor seizure outcome after ATL. Therefore, all cases of drug-resistant TLE should be referred to a surgical center at the earliest.