Prognostic Factors and Longitudinal Change in Long-Term Outcome of Frontal Lobe Epilepsy Surgery.

OBJECTIVE

We aimed to investigate the possible predictive factors and longitudinal change in long-term surgical outcome after refractory frontal lobe epilepsy surgery.

METHODS

We retrospectively reviewed 82 patients who underwent frontal lobe resection. Invasive monitoring was performed in 43 patients. All patients were followed-up for a minimum of 3 years after surgery. Univariate and multivariate analyses were used to evaluate the predictors. The Kaplan-Meier survival curve showed the estimated probability of complete seizure freedom, and a favorable outcome was defined as Engel class I at the last follow-up.

RESULTS

The estimated probability of complete seizure freedom was 57.3% at 1 year postoperatively, 51.2% at 2 years, and 50.0% at 5 years. Factors predictive of worse long-term outcome were lack of a lesion in the frontal lobe on magnetic resonance imaging, generalized/nonlocalized ictal discharge, use of subdural grids, and acute postoperative seizure (APOS). After the surgery, 44 patients (53.7%) had seizures at any time during the first 2 years. Five of 44 patients had seizure freedom at the last follow-up. After a seizure-free period of at least 6 months, seizure recurred in 6 patients by 6 months to 1 year (early recurrence) and in 9 patients by 1-3 years (late recurrence). Eight of 43 (18.6%) seizure-free patients had discontinued drugs.

CONCLUSIONS

The overall seizure outcome after surgery changed most during the first 2 years. The presence of frontal focal lesions and ictal frontal rhythm predicted favorable outcome. However, APOS was predictive of early epilepsy recurrence.