Determinants of clinical response to injection laryngoplasty in unilateral vocal fold paralysis: a systematic review and meta-analysis.

Background: Unilateral vocal fold paralysis (UVFP) significantly impairs vocal function, affecting patients' quality of life. Injection laryngoplasty, a primary treatment modality for UVFP, varies in effectiveness based on the material used, injection volume, and procedural nuances. This study aims to systematically analyze how these factors influence treatment outcomes to optimize intervention strategies.

Materials And Methods: The authors conducted a comprehensive meta-analysis and meta-regression using data extracted from 82 studies identified through a robust literature search on databases including PubMed, Scopus, and Web of Science, up to 13 February 2024. Eligible studies were single-armed observational or experimental that reported pre and postoperative data on UVFP patients undergoing their first injection laryngoplasty. The primary outcomes analyzed included maximum phonation time, harmonics-to-noise ratio, fundamental frequency, jitter, shimmer, and subjective voice measures such as the Voice Handicap Index and GRBAS scale components.

Results: The meta-analysis revealed significant improvements in maximum phonation time (MPT) and harmonics-to-noise ratio (HNR) post-injection, with variability in outcomes influenced by injection material and procedural techniques. Meta-regression identified the injection volume and the timing of the procedure as significant predictors of MPT and HNR outcomes, respectively. Materials such as polydimethylsiloxane (PDMS) and autologous fat significantly improved MPT and reduced the grade of dysphonia and roughness, respectively. The type of injection material, volume, and approach was crucial in reducing symptoms of voice handicap and enhancing the overall vocal quality.

Conclusions: Injection laryngoplasty significantly improves vocal outcomes in UVFP patients. The choice of injection material, volume, and timing of the intervention play pivotal roles in determining the effectiveness of the procedure. Tailored treatment approaches based on these factors are recommended to enhance therapeutic efficacy and patient satisfaction.