Objective: To evaluate both subjective and objective voice changes after medialization thyroplasty in patients with unilateral vocal fold paralysis, and to assess the time to achieve maximum voice improvement after surgery.

Materials and Methods: Nineteen patients with unilateral vocal fold paralysis and undergoing medialization thyroplasty were recruited from May 2006 to December 2008. Voice recordings were performed before surgery and at 2, 4 and 6 months after surgery. Acoustic analysis (fundamental frequency, highest fundamental frequency, lower fundamental frequency, noise-to-harmonic ratio, and percent of jitter and shimmer) was calculated using the Multidimensional Voice Program. Maximum phonation time, perceptual evaluation, and a self-assessment visual analogue scale were also conducted. Data for the preoperative and three postoperative periods were compared.

Results: Jitter, shimmer, noise-to-harmonic ratio, and maximum phonation time showed significant improvements after medialization thyroplasty, and maximum improvement was found at the second postoperative month, with no significant change among the three postoperative periods. Subjective voice quality and loudness showed maximum improvement at the fourth and sixth months, respectively. Patients’ self-assessment by visual analogue scale showed maximum improvement at the fourth postoperative, with up to 80% of their normal voice.

Conclusion: All objective measurements revealed maximum voice improvement at the second month after medialization thyroplasty, with marginal improvement thereafter. The subjective measurements demonstrated an improvement up to 80% of normal voice after surgery.

Keywords: Medialization thyroplasty, Laryngoplasty, Vocal fold paralysis, Voice, Acoustic analysis, Aerodynamic analysis