Withdrawal of antiepileptic drugs after neocortical epilepsy surgery

Abstract

Objective: This study investigated the prevalence of successful antiepileptic drug withdrawal and identified predictors of seizure recurrence after antiepileptic drug reduction following resectional operation for intractable neocortical epilepsy.

Methods: We retrospectively assessed 223 patients (100 with neocortical temporal lobe epilepsy, 69 with frontal lobe epilepsy, 23 with parietal lobe epilepsy, 25 with occipital lobe epilepsy, and 6 with multifocal epilepsy) who underwent surgery. The mean period of observation was 84.4 months (range, 24-152 months) after surgery and 72.6 months (range, 12-138 months) after initial reduction. Clinical characteristics, magnetic resonance imaging, and surgical parameters were evaluated for their potential to predict recurrence associated with antiepileptic drug withdrawal.

Results: Antiepileptic drug reduction was attempted in 147 patients (65.9%), 78 (53.1%) of whom had seizure recurrence after initial reduction. Discontinuation was achieved in 73 patients (32.7%), and 59 (80.8%) of these remained seizure free until final assessment. Multivariate analysis revealed that early drug tapering, normal magnetic resonance imaging results, seizure before reduction, and longer epilepsy duration were associated with recurrence. Finally, 27.4% of patients were seizure free without drugs, and 26.9% were seizure free with drugs. Compared with preoperative status, the number of antiepileptic drugs needed decreased in 50.7% of patients, did not change in 19.3%, and increased in 30.0% after surgery.

Interpretation: The complete-cure rate of intractable neocortical epilepsy by resectional surgery was 27.4%. When patients undertake early tapering, and have normal magnetic resonance imaging results, seizure before reduction, and longer disease duration, further withdrawal should be done cautiously because of the high risk of relapse.