[The efficacy of ansa cervicalis anterior root for unilateral recurrent laryngeal nerve injury].

Objective: To discuss the long-term efficacy of laryngeal reinnervation using the anterior root of the ansa cervicalis in the treatment of unilateral vocal fold paralysis (UVFP) caused by thyroid surgery. Method: From January 2010 to January 2016, a total of 39 UVFP patients who underwent ansa cervicalis anterior root-to-recurrent laryngeal nerve (RLN) anastomosis and who had suffered nerve disfunction for 6 to 24 months were enrolled as UVFP group.Another 39 age and gender matched normal subjects served as control group. Videostroboscopy, vocal function assessment (acoustic analysis, perceptual evaluation and maximum phonation time), and laryngeal electromyography were performed preoperatively and postoperatively for assessing surgery efficacy. Paired sample t test was used for statistical analysis. Result: Videostroboscopic reports indicated that the glottic closure, vocal fold edge, vocal fold position, phase symmetry and regularity were significantly improved in the UVFP group ( P <0.01, respectively, postoperative vs. preoperative)and showed no statistical differences compared to the control group ( P >0.05, respectively). Both the postoperative GRBAS assessment and acoustic parameters were also significantly improved in the UVFP group, Pre-operative acoustic parameters/Post-operative acoustic parameters were 1.68±0.82/0.39±0.27, 10.08±2.56/4.58±2.96, 0.203±0.216/0.018±0.038, 5.96±1.92/17.42±4.11( P <0.01, respectively) and Pre-operative acoustic parameters/Post-operative acoustic parameters were 0.39±0.27/0.32±0.19, 4.58±2.96/3.32±1.27, 0.018±0.038/0.014±0.027, 17.42±4.11/18.76±5.29, which showed no statistical differences compared to the control group ( P >0.05, respectively). Conclusion: Delayed laryngeal reinnervation with the anterior root of ansa cervicalis, it can restore the physiological laryngeal phonatory function to the normal or a nearly normal voice quality, which is a feasible and effective approach for the treatment of thyroid surgery-related UVFP.