Vocal Cord Abduction by Regenerated Recurrent Laryngeal Nerve: An Experimental Study in the Dog

Abstract

Although the laryngeal muscles can be reinnervated by a repair of the recurrent laryngeal nerve after its complete division, the vocal cord does not abduct and continues to act as an obstruction in the airway. This loss of abduction is due to simultaneous contraction of the adductor and abductor muscles during inspiration. After selective section of the adductor nerve branches within the larynx, the vocal cord abducts with each inspiration. Abduction is strongest during hyperpnea or airway obstruction below the larynx. Loss of adductor power during phonation appears to be compensated for by the cricothyroid muscle. Reflex protective closure of the larynx, on the other hand, may be weakened or lost by denervation of the adductors. It produced no dysphagia or aspiration in the one dog experimented upon.