声帯内自家脂肪注入術の臨床・組織学的研究

Abstract

Injection laryngoplasty is a reliable surgical procedure to correct laryngeal incompetence caused by vocal fold paralysis. Although autologous fat has become a popular injection material in recent times, there are numerous problems that need to be addressed in its application in laryngoplasty; such as, injection site of the vocal fold, quantity of injection material, possibility of improvement for glottal gap, and resorption of injected autologous fat. The purpose of this study is to investigate the problems of autologous fat injection in laryngoplasty.The clinical study involved 31 patients with unilateral vocal fold paralysis who had received treatment at the Kurume University Hospital between 2000 and 2003. The pathological study was comprised of 23 patients whose autologous fat harvested by liposuction was utilized as injection material during laryngoplasties between 2000 and 2005.In patients with a small degree of vocal fold bowing, autologous fat was injected locally into the thyroarytenoid muscle lateral to the oblong fovea of the arytenoid cartilage. As a result, the glottal gap decreased and postoperative voice functions, maximum phonation time (MPT) and mean airflow rate during phonation over comfortable duration (MFRc) improved. In patients with a large degree of vocal fold bowing, the autologous fat was injected not only into the thyroarytenoid muscle lateral to the ob-long fovea of the arytenoid cartilage but also into the thyroarytenoid muscle at the membranous portion of the vocal fold. As a result, the glottal gap decreased and postoperative voice functions, MPT and MFRc improved.The fat cell membranes had not been damaged during liposuction harvesting or microinjection by our technique. The diameters of fat cells ranged from 41.3±8-117.1±15.2μm. A few patients with large diameter fat cells showed less improvement compared to those with smaller diameters for the postoperative voice functions, MPT, MFRc, and pitch perturbation quotient (PPQ).These results indicate that fat injection into the thyroarytenoid muscle lateral to the oblong fovea of the arytenoid cartilage produced good postoperative voice function and this procedure can improve a large degree of glottal gap. Resorption of autologous fat may be related to not only the size and density of fat cells but also their proliferation.