Neuromodulation in Intractable Epilepsy Through Responsive Vagal Nerve Stimulation: A Three-Year Retrospective Study at the University of Texas Medical Branch, Galveston.

Joseph Villarreal,Prashant Rai,Kyra Curtis,Neeharika Thottempudi,Todd Masel,Sama Elrahi,Andrea Gil Guevara,Ruiqing Sun,Vijaya Lakshmi Valaparla,Bhanu Gogia

doi:10.7759/cureus.18698

Abstract

Background: Vagus nerve stimulation (VNS) functions through neuromodulatory mechanisms to provide quality of life improvements to those with drug-resistant epilepsy. Responsive VNS (rVNS) generators are designed to further reduce seizure burden by detecting ictal tachycardia and aborting seizures soon after their onset. Methods: Electronic medical records were accessed from January 2015 to December 2018 to identify patients with epilepsy managed with rVNS generators. Data were collected on seizure burden before and after rVNS implantation. Seizure burden was compared using t-tests, and monthly seizure reductions were gauged with the McHugh scale. Twenty-seven individuals met inclusion criteria; 10 were eliminated due to prior VNS implantation or undocumented seizure frequencies.Results: The average seizure burden prior to rVNS implantation was 24.78 seizures/month. Following generator placement, the mean seizure frequencies at three months, six months, 12 months, and 18 months were 6.81, 16.57, 5.65, and 5.78 seizures/month, respectively. However, despite documented reductions in the average monthly seizure frequency, we found no statistically significant differences in seizure frequency relative to baseline.Conclusion: While many participants showed individual reductions in seizure burden, this study was unable to definitively conclude that rVNS therapy leads to statistically significant reduction in seizure burden.

Highlights

Epilepsy has the potential to severely impair a patient’s quality of life; several pharmacological modalities have been synthesized to allow a reduction in seizure burden
Demographic variables were extracted from medical records of patients treated with Responsive VNS (rVNS) therapy
No patients in this study experienced life-threatening adverse events. These findings suggest that rVNS therapy is a safe, and potentially efficacious, therapy for the management of epilepsy

Summary

Introduction

Epilepsy has the potential to severely impair a patient’s quality of life; several pharmacological modalities have been synthesized to allow a reduction in seizure burden. A diverse array of nonpharmacological treatments exists for individuals with drug-resistant epilepsy, each best suited for a particular patient presentation. It is curative only in up to 70% of these individuals [2,3] Their use is limited by the ability to locate a seizure focus and safely remove aberrant tissue. Neuromodulation is an important modality to consider in patients with intractable epilepsy to reduce their seizure burden [2,3]. Vagus nerve stimulation (VNS) functions through neuromodulatory mechanisms to provide quality of life improvements to those with drug-resistant epilepsy. Responsive VNS (rVNS) generators are designed to further reduce seizure burden by detecting ictal tachycardia and aborting seizures soon after their onset

Methods

Results

Discussion

Conclusion