Stimulated Vocal Fold Immobility after Vagal Nerve Stimulator Placement: A Case Series

Introduction: Vagal nerve stimulator (VNS) implantation is a vital therapy for epilepsy refractory to other treatments; however, it is associated with a very high rate of voice changes. Relatively few of these patients are evaluated for vocal fold motion impairments. In this series, we evaluate 5 such patients with a novel phenotype of forced abduction with VNS stimulation. Methods: Retrospective case series. Results: Five patients with a VNS implant who underwent operative direct or in-office rigid laryngoscopy and had vocal fold motion impairment associated with VNS activation are included. All 5 patients had vocal fold mobility with VNS off and a fixed with activation. All patients exhibited vocal fold abduction with VNS activation. Patient 2 has since undergone laryngeal reinnervation, which helped her intermittent dysphonia but left a small glottic gap. A type 1 thyroplasty corrected this gap and improved her voice further. Patient 3 has undergone laryngeal reinnervation for which early results show improvement in perceptual and patient reported outcomes. Patients 4 and 5 have both undergone laryngeal reinnervation with improvement in voice. Conclusion: Previous reported cases of stimulated immobility associated with VNS use describe only adduction of the vocal fold. This series expands the previous work showing the VNS activation can also cause stimulated immobility in an abducted position, for which reinnervation and other medialization procedures offer promising treatment.