Right‐sided vagus nerve stimulation: Worldwide collection and perspectives

Abstract Objective Vagus nerve stimulation (VNS) is an established therapy for drug‐resistant epilepsy (DRE) and is indicated for implantation on the left vagus nerve‐only. In rare cases right‐sided VNS may be the only option. With only seven published cases in the literature, data on safety and effectiveness of right‐sided VNS is very limited. Methods An anonymous 38‐item questionnaire was sent to expert surgeons implanting VNS for DRE. The questions covered demographics and clinical characteristics, the reason for right‐sided implantation and both neurological and surgical outcomes of right‐sided VNS. Results The survey captured 38 cases of right‐sided VNS (18 females, mean age at surgery of 28.0 ± 16.3 years). Right‐sided VNS was performed because of VNS lead deficiency ( n = 20), anatomical constraints ( n = 8), infection of a left‐sided VNS site ( n = 9), and presence of a left ventricular shunt ( n = 1). Thirty‐two patients (84%) had a preoperative cardiac assessment. Three patients presented postoperative cardiac side‐effects. Right‐sided VNS was stopped at last follow‐up in three patients: due to deep infection ( n = 1), due to dyspnea ( n = 1), and due to sleep apnea syndrome ( n = 1). Twenty‐one patients (55%) were responders to right‐sided VNS and the mean reduction of seizure frequency under right‐sided VNS was 56.2 ± 18.8%. Focusing on seizure frequency reduction between right‐sided VNS and left‐sided VNS: 20 patients experienced similar effectiveness, 1 experienced lesser effectiveness, and 2 patients experienced greater effectiveness with right‐sided VNS. Interpretation This multicenter case series significantly augments the available literature on right‐sided VNS. This suggests comparable effectiveness to left‐sided VNS but potentially lower tolerability. Further studies are warranted to better evaluate safety and efficacy of right‐sided VNS.