Vagus Nerve Stimulation as a Treatment for Refractory Epilepsy: A 15-Year Experience in an Italian Tertiary -Care Epilepsy Center

Purpose: Vagus Nerve Stimulation (VNS) is indicated in the treatment of pharmacoresistant epilepsy. Albeit its general efficacy, the use of VNS remains undefined concerning two points: i) there are only a few long-term studies, none randomized; ii) there are no clinical markers which allow to predict VNS response. In order to explore these points, we report the long-term outcomes of VNS in 22 patients. Methods: Twenty-two patients with refractory epilepsy, either symptomatic generalized or cryptogenic/symptomatic partial were treated with VNS and monitored up to 15 years (6.5+/-1.1). Results: No significant adverse events were observed. VNS efficacy was enduring and increased significantly over time. Seizure frequency decreased by 34.3+/-3.9% after 1 year, 40.3+/-4.6% after 2 years, 48.0+/-5.4% after 3 years, 53.4+/-7.9% after 5 years and 48.1%+/-5.8 at maximum follow up. Data on syndrome-specificity were not significant (small number of patients in each group). Conclusions: This study confirms sustained efficacy of VNS in epilepsy. Generalized symptomatic and temporal lobe epilepsy seem to be associated to a better outcome to VNS, but additional data are required.