Type III Thyroplasty for Patients With High-Pitched Voice Disorders: A Systematic Review and Meta-analysis

Introduction: Type III thyroplasty can be performed to treat high-pitched voice disorders, encompassing both cisgender men with mutational dysphonia and transgender men dissatisfied with vocal pitch after gender-affirming hormone treatment. We aimed to clarify the effect of type III thyroplasty on the fundamental frequency (F0) of the voice, with subgroup comparisons.

Methods: This study adhered to PRISMA guidelines. A comprehensive search was performed in PubMed, Cochrane Library, Scopus, Science Direct, LILACS, and Google Scholar, with no constraints on publication date. We included studies conducted in English, Portuguese, or Spanish that assessed cisgender and transgender male patients who underwent type III thyroplasty for high-pitched voice disorders. The primary outcome was the F0. Patient demographics, technical aspects of the procedure, and perioperative care data were extracted. A meta-analysis with inverse variance, random-effects model was performed.

Results: The PRISMA approach yielded 10 studies, totaling 99 patients with mean age of 29.2 years (17 to 55 years) and average follow-up time of 7.8 months (0.3 to 60 months). Of them, 15 patients (15.1%) had sulcus vocalis (secondary mutational dysphonia) and 8 patients (8.1%) were transgender men. Thyroplasty was made predominantly bilaterally (n = 95; 95.9%). Mean global F0 difference pre and post-surgery was -74.9 Hz (95% CI -88 to -61.9; p < 0.01; I2 = 74%). The reduction in F0 was more pronounced in cisgender men compared to transgender men (77.8 ± 26.6 Hz vs 49.0 ± 14.2 Hz; p = 0.003) and in primary mutational dysphonia compared to secondary (75.7 ± 25 Hz vs. 59.9 ± 17 Hz; p = 0.02). One complication (1%) was reported. There was significant heterogeneity between studies regarding surgical technique, perioperative care, and acoustic analysis of voice.

Conclusions: Type III thyroplasty significantly lowers F0 in high-pitched voice disorders, particularly in cisgender men and those with primary mutational dysphonia. However, conclusive evidence regarding its impact on quality of life and other acoustic voice parameters is still inconclusive.