Efficacy and safety of using vagus nerve stimulation in patients with pharmacoresistant epilepsy in the Russian Federation: a multi-center retrospective observational program
Authors: Voronkova K. V. , Klochkov M. N. , Koroleva N. Yu. , Ivanov S. S. , Dmitriev A. B. , Bolshakova E. S. , Fatykhova E. F. , Usoltseva A. A. , Dmitrenko D. V. , Feygina A. A. , Koshelyaevskaya Ya. N. 
Published: July 2021

Objective: to assess efficacy and safety of vagus nerve stimulation (VNS) in patients with pharmacoresistant epilepsy.

Material and methods. A multi-center retrospective observational program was applied in patients with pharmacoresistant epilepsy by using vagus nerve stimulation for at least 2 years. There were enrolled 151 subjects, patient age on stimulator implantation varied from 5 to 65 years (24.4±13.1 years). Among them, subjects under 18 or at least 18 years of age comprised 58 (38.4%) and 93 (61.6%), respectively. Changes in rate and severity of major group epileptic seizures (highly disabling type) 24 months after VNS-therapy vs. baseline state as well as during 3-, 6-, 9-, 12-month follow-up were compared. There were assessed stimulator-related effects on VNS-therapy as well as patient quality of life 2 years after therapy. The dynamics of the frequency of all types of epileptic seizures was evaluated according to McHugh Outcome scale.

Results. Mean epilepsy duration on stimulator implantation was 170.9±126.8 months, with maximum up to 666 months (55 years). Number of patients with dominant (disabling) seizures on implantation procedure comprised 136 (90.1%). Decline in dominant epileptic seizure rate by 50–99% was recorded in 91 patients (66.9%) 24 months after VNStherapy. Among such subjects were 41 patients (30.15%) featured with disabling seizures including 24 fully seizure free subjects (17.65%). Decreased rate of all group epileptic seizures by more than 50% (responders) was found in 52.9% cases, including subjects under 18 and adults in 63.9% and as few as 46.3% (p<0.05), respectively. While assessing dynamic rate for all groups of epileptic seizures applied with VNS-therapy by using McHugh Outcome scale it was found that class I (lowered seizure rate by 80–100%) was observed in 44 cases (29.1%), including 18 patients under 18 (31%) and 26 subjects above 18 (28%) (insignificant difference). Mean dominant group epileptic seizure rate was also significantly decreased in both age groups from 20 down to 5.7 per month. Severity of epileptic seizures and postseizure condition upon VNS-therapy was decreased in 38.6% and 43.9% patients 24 months after therapy and on final follow-up visit, respectively (more than 24 months after implantation). No serious adverse events as well as adverse effects resulting in therapy cancel were noted. Conclusion. Vagus nerve stimulation is an effective and safe auxiliary treatment method for therapy of pharmacoresistant epilepsy both in children and adults.><0.05) , respectively. While assessing dynamic rate for all groups of epileptic seizures applied with VNS-therapy by using McHugh Outcome scale it was found that class I (lowered seizure rate by 80–100%) was observed in 44 cases (29.1%), including 18 patients under 18 (31%) and 26 subjects above 18 (28%) (insignificant difference). Mean dominant group epileptic seizure rate was also significantly decreased in both age groups from 20 down to 5.7 per month. Severity of epileptic seizures and postseizure condition upon VNS-therapy was decreased in 38.6% and 43.9% patients 24 months after therapy and on final follow-up visit, respectively (more than 24 months after implantation). No serious adverse events as well as adverse effects resulting in therapy cancel were noted.

Conclusion. Vagus nerve stimulation is an effective and safe auxiliary treatment method for therapy of pharmacoresistant epilepsy both in children and adults.