Newer techniques of laryngeal reinnervation.

We relate the experience obtained in the use of the right superior laryngeal nerve (motor branch)--cricothyroid muscle pedicle flap in dogs in an attempt to reinnervate the right posterior cricoarytenoid muscle (PCA). The right vocal cord was paralyzed by severance and removal of 2.5 cm of the right recurrent laryngeal nerve. Evaluation 6 months postoperatively revealed the vocal fold remobilization on the right side to have an average of about one half the mobility of the left, normal side. After the recurrent laryngeal and superior laryngeal nerves on the left were severed, the vocal cord mobility dropped to only about one fourth. This suggests that the dogs had contralateral reinnervation. Nevertheless, the right vocal cord mobility, driven only by the right superior laryngeal nerve, was enough to secure an adequate airway without the need for a tracheotomy. This experiment was statistically significant on comparison with a control group. Electromyographic studies as well as PCA histochemistry were performed.