Results of vagal nerve stimulation in patients with pharmacoresistant epilepsy in a national epilepsy referral centre

Aim. To describe clinical results and complications derived from vagal nerve stimulation therapy in drug resistant epileptic patients unsuitable for other surgical treatments, since the first implant in an epilepsy national referral centre. Patients and methods. A retrospective analysis of the patients implanted in our centre was held. Data related to baseline characteristics of their epilepsy and therapy complications was collected. Results. 32 new implants in 31 patients are included, mean age of 34 years, 29.3 years of disease evolution, three antiepileptic drugs at surgery and a postoperative follow-up of 4.03 years. Complex partial seizures types (71.9%) and cryptogenic aetiology (59.4%) were the most frequent. 75% of patients hadn't history of previous epilepsy surgery. 43.8% of patients had a seizure frequency improvement above 50%, with a better response in patients with complex partial seizures (p = 0.22) and cryptogenic aetiology. None statistical significance was found between antiepileptic drugs and seizure frequency. Dysphonia, hoarseness and dysphagia, mostly transient, were the side effects registered. There was an asystole during surgery, completely recovered. One device was replaced due to hardware rupture after a seizure related trauma, one had to be adjusted due to a previous vocal cord paresis, and one dysfunctioning device was removed. In 84.4% the tolerance was excellent. Conclusions. Vagal nerve stimulation is an effective treatment for significant seizure frequency improvement of resistant patients untreatable with other medical or surgical treatments. Further studies are needed to predict the individual response of each patient to therapy and optimizing indications, therefore contributing to cost/benefit optimization.