[Treatment of bilateral vocal cord paralysis by hemi-phrenic nerve transfer]

Objective: To investigate the surgical effect of reinnervation of bilateral posterior cricoarytenoid muscles(PCA) with left hemi-phrenic nerve and endoscopic laser arytenoid resection in bilateral vocal cord fold paralysis(BVFP) and to analyze the pros and cons of the two methods. Methods: One hundred and seventeen BVFP patients who underwent reinnervation of bilateral PCA using the left hemi-phrenic nerve approach (nerve group, n=52) or laser arytenoidectomy(laser group, n=65) were enrolled in this study from Jan.2009 to Dec.2015.Vocal perception evaluation, video stroboscopy, pulmonary function test and laryngeal electromyography were preformed in all patients both preoperatively and postoperative1y.Extubution rate was calculated postoperative1y. Results: Most of the vocal function parameters in nerve group were improved postoperatively compared with preoperative parameters, albeit without a significant difference(P>0.05), while laser group showed a significant deterioration in voice quality postoperative1y(P<0.05). The two groups showed significant difference in voice quality postoperative1y(P<0.05). Videostroboscopy showed that vocal fold on the operated side in both groups could abduct to various extent postoperatively, which showed significant difference when compared with preoperative abductive movements (P<0.05). But the amplitude in nerve group was larger than that in laser group (P<0.05). 89% of the patients in nerve group were inhale physiological vocal cord abductions. Postoperative glottal closure showed no significant difference in nerve group (P>0.05), while showed various increment in laser group(P<0.05). Differences between the two groups were statistically significant(P<0.05). The pulmonary function in both groups was better after operation, reaching the reference value. Postoperative laryngeal electromyography confirmed successful reinnervation of the bilateral PCA muscles. The decannulation rate were 88.5% and 81.5% in nerve group and laser group respectively. In both groups, patients presented aspiration symptoms postoperatively, and rdieved soon, except 2 patients in laser group suffered repeated aspiration. Conclusions: Reinnervation of bilateral PCA muscles using left hemi-phrenic nerve can restore inspiratory vocal fold abduction to a satisfactory extent while preserving phonatory function at the preoperative level without evident morbidity, and do not affect swallowing function, greatly improving the quality of life of the patients.