Long-term treatment with vague nerve stimulation in patients with refractory epilepsy

Objective: To perform an open-label, long-term efficacy and safety/tolerabi lity study of vague nerve stimulation (VNS) of 454 patients with refractory epilepsy. Methods: Subjects were enrolled from five clinical trials of VNS between 1988 and 1995 after undergoing an implantation of a pulse generato r in the chest and a left cervical vagus nerve-stimulating lead coil. Patie nts were assessed at 6-month intervals until device approval. Seizure frequ encies, medication treatment, and adverse events (AEs) were recorded and en tered into a database. Results: A total of 454 patients were implanted, and 440 patients yielded assessable data. A greater than or equal to 50% seizu re reduction postimplantation occurred in 36.8% of patients at 1 year, in 4 3.2% at 2 years, and in 42.7% at 3 years. Median seizure reductions compare d with baseline mere 35% at 1 year, 44.3% at 2 years, and 44.1% at 3 years. Most common AEs postimplantation at 1 year were hoarseness (28%) and parae sthesias (12%), at 2 years were hoarseness (19.8%) and headache (4.5%), and at 3 years was shortness of breath (3.2%). Continuation rates were 96.7% a t 1 year, 84.7% at 2 years, and 72.1% at 3 years. Conclusion: Long-term, op en-label vagus nerve stimulation (VNS) provided seizure reduction similar t o or greater than acute studies, for median reductions and for those reachi ng a greater than or equal to 50% seizure reduction. VNS remained safe and well tolerated, with nearly three-quarters of the patients choosing to cont inue therapy.