Long-Term Efficacy and Quality-of-Life Changes After Vagus Nerve Stimulation in Adult Patients With Drug-Resistant Epilepsy

There is a current need to understand the efficacy and quality of life (QoL) outcomes of vagus nerve stimulation (VNS). Identifying patients most likely to benefit from VNS could aid in their selection, reduce side effects, and improve outcomes. Here we studied clinical and QoL outcomes after VNS in patients with drug-resistant epilepsy and attempted to identify response predictors. This was a retrospective study of 55 patients with drug-resistant epilepsy treated surgically during 2004-2018, 40 of whom were eligible for inclusion in the analysis. All surgeries were performed using a standard protocol by a neurosurgeon experienced in epilepsy treatment after referral by an attending neurologist. Data were collected from medical records and through a 28-item questionnaire on seizure frequency, duration, and strength before and after VNS, as were the number and type of postoperative complications and their significance to the patient, and QoL based on the 31-item Quality of Life in Epilepsy questionnaire. Improvements in seizure frequency, duration, and strength were observed in 65% of the patients with drug-resistant epilepsy treated using VNS. The most common complication was hoarseness (70%), and complications were poorly tolerated by 12% of the patients. Repeated surgery to replace batteries or electrodes was required in 20% of the patients. Health status was the only QoL parameter significantly impacted by VNS. No significant efficacy predictors were identified. Efficacy across the first month of treatment is a strong indicator of long-term outcomes of VNS. The stimulator can be removed if it does not provide any benefit.