Long-Term Postoperative Vocal Function after Thyroplasty Type I and Fat Injection Laryngoplasty

Abstract

We evaluated the differences in the long-term functional results of medialization thyroplasty type I (MT) and autologous fat injection laryngoplasty (FIL) in patients with unilateral vocal fold paralysis. Forty-one patients underwent MT, and 73 patients underwent FIL. The voice functions before and after both surgeries were examined by aerodynamic, pitch and intensity, and acoustic analyses. The postoperative voice examinations were performed 12 months (median) after the MT, and 4 years (median) after the FIL. The differences between the preoperative and postoperative parameters were examined with a paired t-test for each group separately. For each variable, a comparison of the effects of surgery was conducted with an analysis of covariance model, with the change between the preoperative and postoperative values as the dependent variable and the preoperative value as the covariate. In both groups, all parameters significantly improved after surgery. In particular, there was a significant difference for the postoperative acoustic analyses. However, the aerodynamic analysis after FIL improved more significantly in comparison to that after MT because of the respiratory handicap. We found that MT and FIL provided almost the same effectiveness, and that both surgeries were reliable in improving the vocal function in patients with vocal fold paralysis.