Objectives To investigate the long-term clinical efficacy and stability of thyroplasty type I for unilateral vocal cord palsy, and to identify the appropriate timing of posttreatment evaluations for determination of long-term voice outcome.
Study Design Single-institution retrospective study.
Setting Academic tertiary referral centers in Korea.
Patients Forty patients with unilateral vocal cord palsy who underwent thyroplasty from January 1, 1996, through December 31, 2006, and were followed up for at least 5 years after the surgical procedure.
Interventions Thyroplasty type I under local anesthesia.
Main Outcome Measures Acoustic and aerodynamic analyses of voice were performed on the day before the operation and at preset intervals afterward. Two blinded speech-language pathologists performed the perceptual evaluation.
Results The GRBAS scale (grade of hoarseness, roughness, breathiness, asthenia, and strain) values showed significant improvement at 6 months after the operation (P < .05); these improvements continued up to 1 year and were maintained 5 years after the operation. Acoustic measurements of shimmer and jitter began to show significant improvement at 6 months after the operation, and fundamental frequency and noise harmonic ratios evidenced significant improvement at 1 year (P < .05); these improvements were maintained, to a significant extent, at 5 years after the operation. Aerodynamically, the maximum phonation time, glottal flow rate, and peak subglottic pressure improved significantly from before the operation to 6 months and 1 year after the operation, attaining near-normal values at 1 year afterward (P < . 05)
Conclusions Thyroplasty type I may provide evidence that voice outcome progressively evolves during the first years after the surgical procedure, and that subsequent vocal improvement presented long-lasting stabilization. To assess the long-term voice quality, it may be enough to perform the voice evaluation at 1 year after the procedure.