Randal C. Paniello, MD, Patty Lee, MD, J. David Dahm, MD

The hypoglossal nerve is a logical donor nerve for reinnervation of unilateral vocal fold paralysis because 1) it is normally active when the larynx is adducting, during speech, and during deglutition; 2) it is a large nerve with many axons; and 3) donor site morbidity is low. This method of laryngeal reinnervation has not been previously reported. Hypoglossal-to-recurrent laryngeal nerve anastomosis was performed on a series of 5 dogs. The first dog failed due to technical error. In the remaining 4 dogs, the vocal folds were viewed monthly through a permanent tracheostomy, and the presence of spontaneous vocal fold adduction was observed with the dogs awake at 2 to 4 months. Vocal fold motion was synchronous with spontaneous tongue motion, and complete glottic closure was seen with swallowing. Previous studies using the ansa hypoglossi for reinnervation have failed to show spontaneous activity. Intraglottic pressure measurements following reinnervation were normal. Phonation was successfully induced by stimulating the transferred hypoglossal nerve while passing air through the glottis. Hypoglossal nerve transfer appears to be capable of successfully reinnervating the paralyzed hemilarynx. The potential advantages and disadvantages of this new technique are discussed.