Dr. Keiichiro Okano

Abstract:

Objective:Conventional therapies for laryngeal paralysis and paresis—voice rehabilitation, laryngeal injection, and surgical medialization—are not sufficient for some patients. We previously demonstrated that basic fibroblast growth factor (bFGF) promotes neuromuscular and muscle regeneration in rat models¹⁾. We therefore investigated whether percutaneous bFGF injections can improve voice function in patients with laryngeal paresis. Methods: We enrolled eight adults with chronic unilateral laryngeal paresis (thyroarytenoid involvement, n = 5; cricoarytenoid involvement, n = 3) who exhibited persistent dysphonia despite prior treatments. Under local anesthesia and laryngeal electromyographic guidance, each patient received 10 µg of bFGF injected into the paralyzed muscle once weekly for three to four sessions. We assessed aerodynamic examination, acoustic analysis, GRBAS scale assessment, laryngeal electromyography²⁾, and vocal fold vibratory amplitude (VFVA)²⁾ pre- and post-treatment. Statistical analysis employed paired t-tests, with p < 0.05 considered significant. Results: Aerodynamic parameters showed no significant change. Acoustic analysis demonstrated significant improvements in jitter and PPQ. GRBAS scores, electromyographic turn counts, and VFVA all improved significantly. Conclusion: Percutaneous bFGF injections promoted neuromuscular regeneration in paralyzed laryngeal muscles, restoring vibratory symmetry, muscle function, and voice quality in patients with laryngeal paresis refractory to conventional therapies. These findings suggest bFGF as a promising adjunctive therapeutic option for this population.