Longitudinal Voice Outcomes After Atelocollagen Injection Laryngoplasty for Vocal Fold Paralysis and Vocal Fold Atrophy/Sulcus

Background: Atelocollagen injection laryngoplasty is a minimally invasive treatment for glottic insufficiency, but the durability of its effects and whether longitudinal responses differ according to the underlying disorder remain unclear. Methods: We retrospectively analyzed prospectively collected clinical data from three institutions. The cohort comprised 92 patients and 142 injection episodes, including 75 patients with vocal fold paralysis and 17 with vocal fold atrophy/sulcus. Acoustic Voice Quality Index (AVQI), maximum phonation time (MPT), and Voice Handicap Index-10 (VHI-10) were evaluated from baseline through 1 year. Longitudinal changes were analyzed using mixed-effects models, and clinically meaningful response was assessed using prespecified criteria. Extended follow-up at 1.5 years and ≥2 years was evaluated in the subset of patients with vocal fold paralysis with available long-term data. Results: In vocal fold paralysis, AVQI, MPT, and VHI-10 improved significantly at all follow-up time points through 1 year. In vocal fold atrophy/sulcus, AVQI and VHI-10 showed significant improvement mainly at 1 and 3 months, whereas MPT did not show consistent improvement. The time-by-disease-group interaction was significant for AVQI (p = 0.006), but not for MPT (p = 0.239) or VHI-10 (p = 0.559). AVQI responder trajectories also differed between disease groups (p = 0.023). In the available long-term subset (n = 19 at each time point), all three outcomes remained significantly improved at 1.5 years and ≥2 years. At ≥2 years, responder rates were 41.9% for AVQI and 48.4% for VHI-10, and MPT functional recovery was 31.6%. Conclusions: Atelocollagen injection laryngoplasty was associated with sustained voice improvement through 1 year in vocal fold paralysis, with improvement also observed at ≥2 years in a selected subset. Effects in vocal fold atrophy/sulcus were less consistently sustained.