Vagus nerve stimulation for refractory epilepsy

Left-sided vagus nerve stimulation (VNS) is a relatively new and efficacious neurophysiological treatment for patients with refractory epilepsy who were rejected for resective epilepsy surgery or who have had insufficient benefit from such a treatment, Animal experiments have shown that electrical stimulation of the vagus nerve san reduce the occurrence and duration of electrically and chemically induced seizures, The precise mechanism of action remains unclear. In 1988 the first vagus nerve stimulator was implanted in humans. Currently more than 7500 patients have been implanted world-wide, Randomized controlled clinical studies have shown a more than 50% reduction in seizure frequency in one third of the patients. Results on long-term treatment indicate that VNS remains effective over time and a trend towards improved seizure control with longer use of VNS was observed. VNS seems equally efficient in children. Hoarseness or voice change during stimulation are the most common side effects. VNS requires a substantial financial investment. Cost-efficacy studies have shown that these costs can easily be payed back by savings in epilepsy related direct medical costs in patients treated with VNS