Medical Student Cleveland Clinic Lerner College of Medicine Cleveland, Ohio
Objective: Vagus nerve stimulator (VNS) devices are employed for treatment of epilepsy and resistant depression but can inadvertently damage the vagus nerve causing vocal cord dysfunction. The objective of this study was to characterize cases of vocal cord dysfunction after VNS implantation and to analyze nationwide trends.
Methods: Adverse events involving VNS devices were identified in the MAUDE database from 1996 to 2020. Analysis included descriptive statistics and temporal trends.
Results: 187 cases of vocal cord dysfunction associated with VNS devices were identified over the study period. A total of 24,290 patient injuries were documented after VNS implantation with seizure (n = 6,362; 26.19%) being the most common patient problem. Vocal cord dysfunction included 78 (41.71%) reports of voice alteration and 57 (30.48%) reports of paresis/paralysis. Zero patient deaths were found to have occurred after VNS surgery involving a vocal cord complication. VNS device problems frequently associated with vocal cord dysfunction were high impedance (n = 15; 8.02%), incorrect frequency delivery (n = 10; 5.35%) and battery problems (n = 11; 5.88%). The number of vocal cord dysfunction events per year peaked in 2012 with 43 cases and ranged from 1 to 43 cases.
Conclusion: Although the number of reports has declined in recent years, vocal cord dysfunction and paralysis still remain a significant pathology seen after VNS surgery. This suggests that patients may benefit from pre-operative laryngeal assessment and that early recognition of vocal cord dysfunction is critical to optimizing post-operative outcomes following VNS device implantation.