Variable Effects of Vagus Nerve Stimulator Cycling on Vocal Fold Motion: A Videographic Case Series

OBJECTIVE(S): Vocal fold paralysis and transiently induced immobility are known sequelae of vagus nerve stimulator (VNS) placement, although reports conflict regarding the induced adduction versus abduction during active cycling. We present the first case series with videographic demonstration of variably induced static position and movement changes during VNS cycling. METHODS: Retrospective chart review. RESULTS: Patients presenting with dysphonia following VNS placement from 2012 to 2023 at a tertiary care center were identified. Eight individuals met inclusion criteria, one male and seven females; median age of 46 (range: 31-60), mean VHI-10 was 25.0 (SD 9.3). Five patients had symptom onset after revision surgery. Three patients had left vocal fold immobility at baseline with five maintaining motion. Transient left immobility was induced in three of five patients with baseline movement. There was no pattern for static adducted versus abducted position relative to baseline. One patient with contralateral right vocal fold hypomobility showed reduction in right sided movement with active VNS cycling. One patient demonstrating adducted position with cycling underwent ipsilateral adductor compartment chemodenervation with onabotulinumtoxinA; cycling induced relatively abducted static position. Reducing the cycling duration, frequency, or intensity improved symptoms in three patients. These changes are highlighted as a case series in videographic supplement. CONCLUSIONS: Dysphonia following VNS placement does not solely result from iatrogenic vocal fold paralysis. Transient dysphonia appears secondary to cyclical vocal fold motion impairment or static positioning with active VNS cycling. Variable effects necessitate an individualized approach, though this may not mitigate the therapeutic challenge patients present.