Laryngeal electromyography-guided hyaluronic acid vocal fold injection for unilateral vocal fold paralysis a prospective long-term follow-up outcome report

IMPORTANCE: Unilateral vocal fold paralysis (UVFP) is a common voice disorder that may cause glottal closure insufficiency with hoarseness of voice. Laryngeal electromyography (LEMG)-guided hyaluronic acid vocal fold (VF) injection has been proposed as a treatment option to improve glottal closure with a satisfactory short-term effect. To our knowledge, this study reports the first long-term follow-up result of this treatment modality. OBJECTIVE: To present the long-term treatment results of LEMG-guided hyaluronic acid VF injection for UVFP. DESIGN, SETTING, AND PARTICIPANTS: Prospective study of the treatment results of 74 patients who received LEMG-guided hyaluronic acid VF injection for UVFP at a tertiary referral medical center from March 2010 to February 2013. INTERVENTIONS: In the office-based procedure, 1.0 mL of hyaluronic acid was injected via a 26-gauge monopolar injectable needle electrode into paralyzed thyroarytenoid muscles by LEMG guidance. MAIN OUTCOMES AND MEASURES: Various glottal closure evaluations such as normalized glottal gap area, maximal phonation time, phonation quotient, mean airflow rate, perceptual GRBAS (grade, roughness, breathiness, asthenia, strain) scale, and Voice Handicap Index were compared before and after injection using the nonparametric Wilcoxon signed rank test within 1 month, at 6 months, and at the last follow-up examination. RESULTS: Sixty patients had been followed up for at least 6 months. Forty-four patients received only 1 injection, and 16 patients received repeated injections (2 injections for 13 patients and 3 for 3 patients). All the glottal closure parameters improved significantly (P < .001) within 1 month, at 6 months, and at the last follow-up examination, with a mean (SD) of 17.4 (8.9) months. At the last follow-up examination, the mean (SD) normalized glottal gap area was significantly reduced from 7.9 (5.7) to 0.6 (1.6). Mean (SD) maximal phonation time was significantly prolonged from 4.6 (3.8) seconds to 12.1 (7.4) seconds. Mean (SD) phonation quotient was significantly reduced from 647 (508) mL/s to 277 (212) mL/s. Mean (SD) airflow rate was significantly reduced from 445 (338) mL/s to 175 (145) mL/s. When all the GRBAS scale parameters improved, the mean (SD) Voice Handicap Index score was significantly reduced from 76 (22) to 38 (30) (all P < .001). CONCLUSIONS AND RELEVANCE: Of the 74 patients in this study, 44 (60%) who received a single injection and 16 (22%) who received repeated injections did not require another treatment after long-term follow-up. Laryngeal electromyography-guided hyaluronic acid VF injection is an option for treating UVFP with satisfactory results.