Clinical analysis of selective laryngeal reinnervation using upper root of phrenic nerve and hypoglossal nerve branch in the treatment of bilateral vocal fold paralysis

Objective: To evaluate the airway and voice quality improvement in patients with bilateral vocal fold paralysis (BVFP) who underwent selective laryngeal reinnervation surgery. Methods: From January 2012 to December 2016, a retrospective study was conducted in 39 patients with BVFP who underwent selective laryngeal reinnervation surgery in Department of Otorhinolaryngology Head and Neck Surgery, the First Affiliated Hospital of Navy Medical University. All patients were examined by videostroboscopy, vocal function assessment, laryngeal electromyography and pulmonary function test before and after the surgery, and followed up for at least 2 years to evaluate the efficacy and safety of the surgery.Wilcoxon signed rank test was used to analyze the G score and VHI-10 score data. Paired t-test was used to analyze acoustic parameters, MPT values and pulmonary function parameters. Results: Postoperative infection and hemorrhage occurred in one patient separately.Videostroboscopic videos showed that at 4-8 months postoperatively, vocal folds in 35 patients achieved moderate or severe abduction during inspiration, 2 patients only achieved mild abduction, 2 patients showed no abduction,while all patients achieved adduction in bilateral vocal cords during phonation. The recovery rate of moderate-to-severe abduction was 89.7% (35/39), and these patients were decannulated successfully. At 12 months after operation, G score and VHI-10 score were significantly lower than those before operation (P<0.05), and the acoustic parameters jitter, shimmer, HNR and MPT were significantly improved (P<0.05). Most of the parameters of the pulmonary function test at 3 months postoperatively returned to the normal reference level, while the maximum inspiratory pressure (PImax) at 12 months after operation was still slightly lower than the normal level, but it was significantly improved compared with preoperative value (P<0.05). The EMG data at 12 months postoperatively showed full interference potentials in 37 patients in bilateral posterior cricoarytenoid muscles during inspiration, and full interference potentials in bilateralthyroarytenoid muscles during phonation. Obvious misdirected regeneration electric activitieswere found in two of them. Potentials in posterior cricoarytenoid muscle were weak in 2 cases with poor abduction. During long-term follow-up, only one case showed decreased abduction, but did not affect respiratory function. Conclusions: The selective laryngeal reinnervation procedure applied in the present study can restore physiological motion of vocal cords. The success rate was high, the curative effect was stable, and the complications were rare. It is worth of promotion.