Right-sided vagus nerve stimulation in humans: an effective therapy?

Vagus nerve stimulation (VNS) is an additive treatment option for refractory epilepsy. The electrode is placed on the cervical trunk of the left vagus nerve. In patients who are not suitable for left-sided vagus nerve stimulation (L-VNS) right-sided vagus nerve stimulation (R-VNS) may be as effective. In animal models epilepsy is sufficiently suppressed by R-VNS. In a 16 years old boy suffering from medically refractory psychomotoric seizures with secondary generalisation, L-VNS reduced the frequency of generalized seizures. A deep wound infection required the removal of the system eight weeks later. Cicatrisation did not allow preparation of the left vagus nerve, therefore we implanted R-VNS with sufficient seizure suppression. However, compared to L-VNS, the effect occurred months later and cardiac symptoms were induced by stimulation of the right vagus nerve. R-VNS seems to be an effective and alternative therapy in selected patients responding to L-VNS where a left-sided reimplantation is not possible. Placement and adjustment of the device should be performed under ECG control. Further studies are necessary to compare the efficacy of L-VNS and R-VNS.