Bridging gaps between the recurrent laryngeal nerve and ansa cervicalis using autologous nerve grafts

We investigated the clinical efficacy of free nerve grafts in bridging gaps between the recurrent laryngeal nerve (RLN) and ansa cervicalis in patients with unilateral RLN injury.

We retrospectively reviewed the charts of 14 patients who underwent relevant free nerve grafting and assessed the clinical outcomes of this procedure.

Between January 2000 and January 2010, 14 patients with unilateral vocal fold paralysis were enrolled in this study. In all patients, the RLN was resected and free nerve grafts were applied to bridge the gap between the distal stump of the RLN and the anterior root of ansa cervicalis during surgery. Videostroboscopy, acoustic analysis, perceptual evaluation, maximum phonation time (MPT), and laryngeal electromyography (EMG) were performed both preoperatively and postoperatively to assess the clinical outcomes.

Videostroboscopic findings showed that glottic closure, vocal fold edge, vocal fold position, phase symmetry, and phase regularity were significantly improved postoperatively (P<0.05), and no paradoxical movements of vocal folds were observed. Perceptual evaluation showed that overall grade, roughness, breathiness, asthenia, and strain were also significantly decreased postoperatively (P<0.05). The acoustic parameters jitter (local) and shimmer (local) and the mean noise-to-harmonics ratio were significantly lower than the corresponding preoperative values (P<0.05). The postoperative MPT values were also significantly longer than the preoperative values. Laryngeal EMG revealed significant improvement in voluntary motor unit recruitment during phonation postoperatively (P<0.05).

Free nerve grafting is an effective procedure in bridging the gap between the RLN and ansa cervicalis in patients with unilateral RLN injury, as well as a safe procedure without obvious morbidity. A satisfactory vocal outcome can be obtained.