Vagus Nerve Stimulation for Epilepsy: An Evidence-Based Approach

Area of Science:

• Neurology
• Neurosurgery
• Epileptology

Background:

• Medical treatment for seizures is effective in 75-80% of patients.
• Epilepsy surgery is an option for drug-refractory cases, but 20-30% are ineligible or fail surgery.
• Vagus nerve stimulation (VNS) presents a therapeutic alternative for highly refractory epilepsy cases.

Purpose of the Study:

• To conduct an evidence-based search for the best available evidence on Vagus Nerve Stimulation (VNS) efficacy.
• To identify patient populations that may benefit from VNS.
• To evaluate the safety and efficacy of VNS in refractory epilepsy.

Main Methods:

• An evidence-based search was performed using PubMed-MEDLINE, EMBASE, LILACS, SciELO, and Cochrane Library.
• Studies were selected based on the PICO scheme (Patient, Intervention, Comparison, Outcome), study design (randomized controlled trials), Jadad score, language, and full-text availability.
• Twenty-eight relevant papers, all from PubMed-MEDLINE, were included in the review.

Main Results:

• Vagus nerve stimulation (VNS) benefits patients over 12 years old with refractory partial seizures, with or without generalization.
• Children may also benefit from VNS, potentially requiring different stimulation parameters.
• Higher stimulation settings are linked to increased side effects like hoarseness, throat pain, cough, and dyspnea.

Conclusions:

• Vagus nerve stimulation (VNS) is a valuable palliative procedure for adult patients with refractory partial epilepsy.
• A 50-60% reduction in seizure frequency can be expected in at least 50% of treated patients.
• Ongoing research is identifying more specific patient groups, including children with secondary generalized epilepsy and certain reflex epilepsies, who may respond better to VNS.