Feasibility of antiepileptic drug withdrawal following extratemporal resective epilepsy surgery.

OBJECTIVE To identify the rate of successful antiepileptic drug (AED) withdrawal after resective surgery and the predictors of postwithdrawal seizure recurrence in patients with extratemporal epilepsy. METHODS We retrospectively analyzed the postoperative AED profile of 106 consecutive patients who had completed 2 or more years after resections involving frontal, parietal, and occipital lobes for AED-resistant epilepsy. To identify the potential predictors of seizure recurrence, we compared the attributes of recurred and nonrecurred groups by univariate and multivariate analyses. RESULTS We attempted AED withdrawal in 94 (88.7%) patients. Forty-four (41.5%) patients had seizure recurrence while reducing AED, of which 14 (31.8%) did not become seizure-free subsequently. On multivariate analysis, an abnormal postoperative EEG and longer preoperative duration of epilepsy predicted seizure recurrence, while early postoperative seizures and presence of gliosis or dysplasia were additional predictors on univariate analysis. At mean follow-up duration of 4.6 years, 63 (59.4%) patients were seizure-free. The cumulative probability of achieving complete AED-free status was 20% at fourth year, 34% at sixth year, 40% at eighth year, and 52% at 10th year after surgery. CONCLUSIONS Following resective extratemporal epilepsy surgery, AED can be successfully discontinued in only in a minority of patients. One-third of patients who recur fail to regain seizure control upon AED reintroduction. Longer duration of epilepsy prior to surgery, abnormal postoperative EEG, early postoperative seizures, and focal gliosis or dysplasia as substrate predispose to seizure recurrence. This information will be helpful in making rational decisions on AED withdrawal following extratemporal resective epilepsy surgery.