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  • Seizure Frequency Following AspireSR® Vagal Nerve Stimulator Implantation - A Single Institution Report

    Final Number:

    Will Coggins BS; Anthony Nguyen BA; Daniel Branch MD, MS; Eric Mong; Rafael Rodriguez MD; Juan R. Ortega-Barnett MD

    Study Design:

    Subject Category:

    Meeting: Congress of Neurological Surgeons 2018 Annual Meeting - Late Breaking Science

    Introduction: Vagal nerve stimulator (VNS) implantation has been shown to benefit some patients suffering from epilepsy and is a safe therapeutic option (1). A newer model, the AspireSR® has shown promising preliminary results, challenging the conventional "rule of thirds" in VNS therapy (2). We sought to validate these results at our institution.

    Methods: We retrospectively analyzed 25 patients who underwent VNS implantation with the AspireSR®, 8 of whom had a previously-implanted VNS and received the new model. We analyzed seizure frequency prior to AspireSR® implantation and following implantation at time points 3 months, 6 months, 1 year, and 1.5 years.

    Results: AspireSR® implantation was associated with a decreased seizure frequency at 3 months post-operatively. However, no statistical significance could be detected between pre-operative seizure frequency and post-operative seizure frequency at 6 months and beyond. For patients who did not previously have VNS implantation, pre-operative seizure frequency strongly predicted seizure frequency at 6 months and 1 year post-operatively. Seizure frequency at 3 months post-op most strongly predicted seizure frequency at 1.5 years post-op, suggesting decreased magnitude of immediate post-op seizure reduction was predictive of subsequent therapeutic failure. It is important to note, however, that data was only available for 13 patients 1.5 years post-surgery.

    Conclusions: Although the AspireSR® has shown promising results in a previous study, these results may not be generalizable. Our data indicated that treatment with the AspireSR® may result in short-term seizure reduction, but a sustained effect past 3 months was not observed. One possibility is that certain patients with higher seizure burden would more likely benefit from the AspireSR®. One potential limitation of our study is that the smaller sample size may lack the power necessary to detect a statistically significant difference, but this is currently early data, and we will analyze more patients for a longer period of time in the future.

    Patient Care: Vagal nerve stimulators represent an emerging means of treating refractory epilepsy. Ictal tachycardia detection by the AspireSR® presents a novel method of potentially reducing the seizure burden in patients. Assessing this device's capabilities at our institution will provide a greater knowledge base for physicians to apply to decision making in their own practices.

    Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of vagal nerve stimulators in treatment of refractory epilepsy; 2) Assess the efficacy of the AspireSR® in reducing seizure frequency based on our institution's experience

    References: 1. Englot DJ, Chang EF, Auguste KI. Vagus nerve stimulation for epilepsy: a meta-analysis of efficacy and predictors of response. Journal of Neurosurgery. 2011; 115(6): 1248-1255. 2. Hamilton P, Soryal I, Chelvarajah R, et al. Clinical Outcomes of VNS therapy with AspireSR® (including cardiac-based seizure detection) at a large complex epilepsy and surgery centre. Seizure: European Journal of Epilepsy. 2018; 58: 120-126.

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