Vagus nerve stimulation in 436 consecutive patients with treatment-resistant epilepsy: Long-term outcomes and predictors of response

article i nfo Objective: The goal of this study was to assess the efficacy and safety of vagus nerve stimulation in a consecutive series of adults and children with treatment-resistant epilepsy (TRE). Methods: In this retrospective review of a prospectively created database of 436 consecutive patients who underwent vagus nerve stimulator implantation for TRE between November 1997 and April 2008, there were 220 (50.5%) females and 216 (49.5%) males ranging in age from 1 to 76 years at the time of implantation (mean: 29.0 ± 16.5). Thirty-three patients (7.6%) in the primary implantation group had inadequate follow- up (b 3 months from implantation) and three patients had early device removal because of infection and were excluded from seizure control outcome analyses. Results: Duration of vagus nerve stimulation treatment varied from 10 days to 11 years (mean: 4.94 years). Mean seizure frequency significantly improved following implantation (mean reduction: 55.8%, P b 0.0001). Seizure control ≥ 90% was achieved in 90 patients (22.5%), ≥ 75% seizure control in 162 patients (40.5%), ≥ 50% improvement in 255 patients (63.75%), and b50% improvement in 145 patients (36.25%). Permanent injury to the vagus nerve occurred in 2.8% of patients. Conclusion: Vagus nerve stimulation is a safe and effective palliative treatment option for focal and generalized TRE in adults and children. When used in conjunction with a multidisciplinary and multimodality treatment regimen including aggressive antiepileptic drug regimens and epilepsy surgery when appropriate, more than 60% of patients with TRE experienced at least a 50% reduction in seizure burden. Good results were seen in patients with non-U.S. Food and Drug Administration-approved indications. Prospective, randomized trials are needed for patients with generalized epilepsies and for younger children to potentially expand the number of patients who may benefit from this palliative treatment.