Efficacy analysis of vagus nerve stimulation for the treatment of drug resistant epilepsy: A report of 110 cases

Abstract

Objective To explore the efficacy of vagus nerve stimulation (VNS) for the treatment of drug resistant epilepsy. Methods The clinical data of 110 patients with drug resistant epilepsy who underwent VNS at Department of Neurosurgery, Provincial Hospital Affiliated to Anhui Medical University (the First Affiliated Hospital of University of Science and Technology of China) from February 2014 to March 2018 were analyzed retrospectively. The frequency and severity of seizures were followed up by outpatient review, and the efficacy was analyzed according to the McHugh seizure outcome classifications. Results The results of McHugh grade of 110 patients were as follows: grade ⅠA in 10 cases, grade ⅠB in 6, grade ⅡA in 25, grade ⅡB in 7, grade ⅢA in 30, grade ⅢB in 8, grade Ⅳ in 1 and grade Ⅴ in 20, and 3 patients were lost to follow-up. There was significant difference in seizure frequency between preoperative and postoperative conditions (P 0.05). In terms of seizure types, there were significant difference in the distribution of the McHugh classifications between patients with seizures of unclassified onset, focal onset and generalized onset (all P<0.05). The frequency of seizures decreased gradually with prolonged VNS stimulation time(P<0.05). Conclusions VNS could significantly reduce the frequency of seizure. VNS has a better effect on seizures with focal onset and generalized onset, while it has a poor effect on seizure types that cannot be classified. With the increase of stimulation time, the therapeutic effect of VNS is gradually improved. However, the age, sex or duration of disease is not related to the effect of VNS. Key words: Epilepsy; Vagus nerve stimulation; Treatment outcome; McHugh seizure outcome classifications