Treatment Of Unilateral Vocal Paralysis Research Articles

Analysis of Voice and Quantitative Measurement of Glottal Gap After Thyroplasty Type I in the Treatment of Unilateral Vocal Paralysis

Thyroplasty type I is one of several surgical treatments in which improving the voice of unilateral vocal fold paralysis is the ultimate objective. The goal of the surgery is the medialization of the paralyzed vocal fold. The purpose of this study is to evaluate the effectiveness of thyroplasty type I through acoustical analysis, aerodynamic measures, and quantitative videostroboscopic measurements. We report on 20 patients with unilateral vocal cord paralysis who underwent thyroplasty type I. We performed preoperative and postoperative video image analysis (normalized glottal gap area) and computer-assisted voice analysis (fundamental frequency, jitter, shimmer, noise-to-harmonic ratio, mean phonation time, mean flow rate, mean subglottic pressure) in all patients. The glottal gap was significantly reduced after thyroplasty type I. Postoperative voice quality was characterized by an improved pitch and amplitude pertubation (jitter and shimmer), phonation time (mean phonation time), and subglottic pressure (mean subglottic pressure). Thyroplasty type I is an effective method for regaining glottal closure and vocal function.

Longitudinal Evaluation of Vocal Function After Thyroplasty Type I in the Treatment of Unilateral Vocal Paralysis

This study investigated longitudinal changes of vocal efficiency and stability after primary thyroplasty type 1. Fifty-three patients with unilateral vocal-fold paralysis underwent vocal-function evaluation preoperatively and at periodic intervals of 1, 3, and 6 months postoperatively. Vocal-function assessment included videostrobolaryngoscopic examination, acoustical and aerodynamic analysis, and perceptual judgment of voice characteristics. Parameters that included glottic-gap size, maximum phonation time, glottic-flow rate, jitter, harmonic/noise ratio, breathiness, hoarseness, loudness, and phrasing showed significant improvement after thyroplasty and remained stable as early as 1 month postoperatively, with only slight fluctuations over a 6-month period. Postoperative voice outcome was not affected by age, sex, duration of vocal symptoms, cause of paralysis, or preoperative pulmonary function.