Voice quality following laryngeal reinnervation by ansa hypoglossi transfer

Abstract

Recurrent laryngeal nerve injury resulting in chronic unilateral vocal fold paralysis has been treated traditionally by implantation of various materials into the paralyzed vocal fold. Although the usage of these techniques, especially Teflon-glycerin paste injection, has been clinically established, they do not restore full functionality to the larynx (abduction, adduction, and vibratory synchronization of the vocal folds). Restoration of these functions, necessary for improved phonation, has been achieved at least on an experimental basis by reinnervation techniques previously described. This study demonstrates excellent human voice quality following reinnervation of the vocal folds in two cases using ansa hypoglossi-recurrent laryngeal nerve anastomosis. Although the reinnervated vocal fold neither abducted nor adducted, it presented itself in the midline for precise apposition with the nonparalyzed cord. Voice data were analyzed within a single subject experimental design at the following intervals; preoperatively, immediately postoperatively, midterm, and long-term (3 and 6 years). The data was analyzed by subjective and objective means, including acoustics and electroglottography. Patient selection, surgical techniques, results, and implications are reviewed.