title: Aberrant recurrent laryngeal nerve reinnervation as a cause of stridor and laryngospasm.
abstract: Unilateral vocal fold paralysis rarely presents with symptoms of stridor, laryngospasm, and dyspnea. Abnormal reinnervation of abductor nerve branches into adductor fibers may be one cause. Four patients have been positively identified by laryngeal electromyography. Two patients presented after thyroid surgery for thyroid neoplasm. One presented after cervical disk surgery. One patient presented after herpes simplex infection with multiple cranial nerve involvement. All patients had new onset of dyspnea with exertion many months after the recurrent nerve injury. Fiberoptic laryngoscopy showed the affected vocal fold to be immobile. However, with hyperventilation and deep inspiration, there was paradoxical adductor motion of the paretic vocal fold. Laryngeal electromyography showed evidence of reduced but intact voluntary motor units in the thyroarytenoid muscle. These motor units fired on inspiration and not on phonation. This pattern was not seen on the normal side. These findings are consistent with paradoxical innervation and/or synkinesis. Each patient was managed by Botox injection into the adductor muscle. Periodic reinjections may be necessary to manage the condition.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Grabscheid Voice Center, The Mount Sinai Medical Center, New York, New York, USA.
authors.forename: Peak
authors.initials: P
authors.lastname: Woo
authors.forename: Manuel
authors.initials: M
authors.lastname: Mangaro
mesh_terms: D000328:Adult; D019274:Botulinum Toxins, Type A / Q000627:therapeutic use; D004576:Electromyography; D005260:Female; D006801:Humans; D007403:Intervertebral Disc / Q000601:surgery; D007431:Intraoperative Complications / Q000503:physiopathology; D007826:Laryngismus / Q000209:etiology*; D008875:Middle Aged; D009465:Neuromuscular Agents / Q000627:therapeutic use; D012009:Recurrent Laryngeal Nerve / Q000601:surgery; D061226:Recurrent Laryngeal Nerve Injuries; D012135:Respiratory Sounds / Q000209:etiology*; D046608:Synkinesis / Q000175:diagnosis / Q000503:physiopathology; D013964:Thyroid Neoplasms / Q000601:surgery; D014826:Vocal Cord Paralysis / Q000209:etiology* / Q000503:physiopathology
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A