A Cross-sectional Analysis of 21,448 Complications from Vagus Nerve Stimulators for Epilepsy Reported by the Food and Drug Administration’s Manufacturer and User Facility Device Experience Database

Introduction: This study summarizes medical device reports (MDRs) associated with adverse events for Vagus Nerve Stimulators (VNS) indicated for epilepsy reported by the Food and Drug Administration’s Manufacturer and User Facility Device Experience (MAUDE) database.

Methods: The MAUDE database was surveyed for MDRs from November 2013-2022 regarding VNS for epilepsy. Event descriptions, device problems, correlated patient consequences, and device models were grouped and analyzed in Python. Based on event description, revision surgeries and other unique events were identified. All data is de-identified and HIPAA-compliant.

Results: 21,448 MDRs met inclusion criteria. High VNS impedance, the most prevalent device malfunction overall (16.7% of MDRs), was the most prevalent factor for 40 of the 299 encountered patient problems and lead to 1001 revision surgeries (3371 total revisions). Included in those 40 were four of the top six occurring patient problems: seizure recurrence (10.6% associated with high impedance; encompassed focal, absence, and grand-mal subtypes), death (1.2%), generalized pain (8.7%), and decreased therapeutic response (13.8%). The next three top cited device malfunctions of lead fracture (11.7% of MDRs), premature end-of-life indicator (2.9%), and battery problem (2.7%) differed widely in their percentage of cases which did not impact patients (59.7%, 91.3%, 35.6%, respectively), highlighting differing malfunction severity. Seizure recurrence, the most prevalent patient impact, was the outcome most associated with high impedance (11.5%), lead fracture (9.1%), battery problem (37.3%), provider failure to interrogate the VNS (7.0%), and low impedance (13.0%), all of which were in the top ten occurring device problems. In general, MDRs spanned a diverse range including device age, hardware, software, and surgeon or manufacturer error.

Conclusion : This study characterizes the most common and consequential side effects of VNS for epilepsy while clarifying likely causes. In addition, outcomes of 264 different device malfunctions were identified including many not ubiquitously present in literature, lending critical perspective to clinical practice.