Unilateral vocal fold paralysis (UVFP) is a common disorder that may cause glottal closure insufficiency and then hoarseness of voice and aspiration during swallowing. We conducted a systematic review and meta-analysis to evaluate whether hyaluronic acid (HA) injection laryngoplasty (IL) is an effective treatment for patients with UVFP. Comprehensive systematic searches were undertaken using PubMed, EBSCO Medline, and Cochrane Library databases. We appraised the quality of studies according to preset inclusion and exclusion criteria. The lengths of follow-up were divided into short-term (3 months or shorter), medium-term (6 months), and long-term (12 months or longer). We performed random-effect meta-analysis to estimate the changes in voice-related quality of life, perceptual evaluation by grading systems, voice lab analysis of maximal phonation time, and normalized glottal gap area, before and after HA IL. Fourteen studies were eligible for the final analysis. The results showed that patients' glottal closure insufficiency could be improved; maximal phonation time could be prolonged; perceptual evaluations of the voice and quality of life were better after HA IL, but the duration of treatment effect varied among different studies. In conclusion, HA IL is an effective treatment for UVFP, which may achieve a long-term effect and therefore reduce the likelihood of requiring permanent medialization thyroplasty.
