Efficacy and safety following two or more years of vagus nerve stimulation (VNS Therapy) in pediatric patients with drug-resistant epilepsy enrolled in a Russian VNS Registry.

Introduction: Following approval in 2009 of vagus nerve stimulation (VNS Therapy) for drug-resistant epilepsy (DRE) in the Russian Federation, this is the first multicenter study across Russia to evaluate the safety and efficacy of adjunctive VNS Therapy.

Methods: The retrospective, observational registry included 58 pediatric patients with DRE (5-17 years old at implantation) who had ≥2 years of VNS. To ensure a robust evaluation process, changes in seizure frequency were evaluated for all seizure types as well as "most disabling" seizures (defined as seizures accompanied by falls, physical trauma, and/or incontinence in the absence of preventative measures).

Results: With 2 years of VNS Therapy, 37 of 49 patients (76%) experiencing the most disabling epileptic seizures had a >50% decrease in frequency of such seizures, and 16 (33%) reported no longer experiencing the "most disabling" seizure type. In addition, based on the McHugh Outcome scale, VNS Therapy had a positive outcome on both frequency and severity of all epileptic seizure types, with a >50% decrease in frequency of all epileptic seizure types noted in 37 of 58 patients (64%), and 31% of patients had a Class I outcome, including 11 patients (19%) who achieved seizure freedom. VNS Therapy also had a positive effect on the frequency of status epilepticus: 13 patients (22%) had status epilepticus prior to implantation with a mean rate of 9.4 ± 17.7 events per year (range, 0-52), and after VNS Therapy, only one patient continued to experience status epilepticus (at 1 event per 4-6 months). VNS Therapy had an acceptable safety profile and no adverse events leading to VNS discontinuation were reported.

Conclusions: The results demonstrate that VNS Therapy is being safely and effectively applied to pediatric patients in the Russian healthcare system.