Learning curve of medialization thyroplasty using a Montgomery™ implant

Type I thyroplasty—also called medialization thyroplasty (MT)—is considered as an effective treatment for glottic incompetence in general and for abductor vocal fold palsy in particular. In the past there have been some concerns about the experience a laryngeal framework surgeon should have in order achieve an acceptable voice outcome. To assess the learning curve of MT performed using the Montgomery^® hard silicone implant. A retrospective study involving 36 patients divided into three consecutive groups (1, 2, 3) of 12 MT patients or six consecutive groups (1a, 1b, 2a, 2b, 3a, 3b) of six MT patients. Outcome measures: acoustic and aerodynamic outcome improvements (δ) compared to the duration of intervention [operative times (OT)]. Data were analysed by Anova, Kuskal Wallis and χ² statistical tests, according to data distributions. OT decreased significantly between groups 1, 2 and 3 with a mean OT of 90.5′, 71.5′ and 56′ (p < 0.001), respectively. Objective δ such as maximum phonation time (MPT) (p 0.376), Estimated Sub-Glottic Pressure (ESPG) (p: 0.675) Shimmer (p: 0.543) and Jitter (p: 0.709) did not show significant improvement. Only the voice handicap index (VHI) δ of group 2 showed significant improvement (p 0.005) compared with the two other groups 1 and 3. Surgeon experience decreases the OT significantly. On the other hand, our study did not show a correlation between surgeon experience and voice outcome measures improvemnts (MPT, ESGP, Shimmer, Jitter).