Abstracts

VNS therapy is a non-drug treatment for refractory seizures, and is indicated for patients with localization-related epilepsy who are not candidate for resective surgery. The general outcome with VNS in patient with intractable epilepsy is a [sim] 30-40% reduction in seizure frequency, or a [sim]40% responder rate. However the role of VNS in patients who have undergone unsuccessful surgical resection is unclear. The purpose of this study was to review the outcome of VNS therapy in patients who have previously failed resective surgery for intractable epilepsy. We studied 15 patients who underwent surgical intervention without success and subsequently received VNS. Surgeries included temporal lobectomy (9), corpus callosotomy (1), frontal resection (1), hemispherectomy (1) and lesionectomy (3). Follow up ranged from 9 month to 4 years (mean 28.5 months). Six out of 15 patients (40%) had more than 50% seizure reduction. One patient (6.6%) had worsening seizures and one patient remained seizure free even after discontinuation of VNS. Seven patients (46.6%) had no significant change in seizure frequency. We also observed that those who had right sided temporal lobe surgery seem to benefit most from VNS. However AED could not be reduced even in those with observed benefit. Effectiveness of VNS in those with intractable seizures after resective surgery is comparable to the effect of VNS in those with intractable seizures considered nonsurgical.