Predictive value of strobovideolaryngoscopy, acoustic and aerodynamic measures in the prognosis of temporally unilateral vocal fold paralysis after thyroidectomy

Abstract

Objective:To investigate the strobovideolaryngoscopy, acoustic and aerodynamic characteristics of transient unilateral vocal ford paralysis（UVFP） after thyroidectomy. Methods:A retrospective analysis was made of 11 patients with temporary UVFP after thyroidectomy who were treated in Department of Otolaryngology and Head and Neck Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University from January 2013 to March 2021; 8 patients with permanent UVFP after thyroidectomy during the same period were included as a control group. The differences in baseline strobovideolaryngoscopy, acoustic and aerodynamic measures were compared between the two groups. Results:The tones of patients with temporary UVFP after thyroidectomy were all normal, and the proportions of abnormal vocal fords（vocal ford bowing, atrophy, and shortening）, ventricular adduction and glottic insufficiency were significantly lower than those of permanent UVFP patients; arytenoid cartilage stability and height mismatch of vocal ford tended to be better than permanent UVFP. The maximal phonation time（MPT） in patients with temporary UVFP was （8.5±4.1） s, which was significantly longer than （3.9±2.1） s in patients with permanent UVFP; fundamental frequency, mean airflow（MeAF） and mean subglottic pressure（SGP） were better in temporary UVFP than those in patients with permanent UVFP, but the difference did not reach statistical significance. Conclusion:None and mild glottic insufficiency, normal tone, ventricular adduction, and vocal ford appearances without vocal fold bowing, atrophy, and shortening, can be served as the predictors for the early recovery of vocal ford movement in temporary UVFP after thyroidectomy. The MPT less than 4 s, and MeAF, and SGP remarkably increased is the predictor of poor prognosis for vocal ford recovery.