Indication and limit of intra-fold autologous fat injection

Abstract

Fifty-two patients with unilateral vocal fold paralysis received intra-fold autologous fat injection. Autologous fat, harvested from the lower abdomen by liposuction, was filtered out and injected through a 19G needle into the vocal fold by endolaryngeal microsurgery. Clinical follow-up including the following parameters was done from one month to three years after the injection : maximum phonation time (MPT), mean airflow rate during phonation over comfortable duration (MFRc), pitch perturbation quotient (PPQ), amplitude perturbation quotient (APQ), and normalized noise energy for 0 to 4 kHz (NNEa). Voice function dramatically improved as compared to the parameters examined before the operation. Injected fat was not absorbed into the surrounding tissue for at least three years. This result demonstrates that intra-fold autologous fat injection by liposuction is simple, and the functional results are durable for patients with unilateral vocal fold paralysis. In particular, this technique was useful in patients whose distance between bilateral arytenoids was more than 10% of the vocal fold length, whose MPT was less than 3 seconds or whose MFRc was more than 400 ml/sec. Indeed, the recovery of voice functions after the injection was satisfactory. If the patient has any glottal gap between vocal processes at phonation before fat injection, fat injection into the oblong pit of arytenoid cartilage can effectively medialize the paralyzed vocal fold. However, when there was a glottal gap between superior and inferior distance at phonation, intra-fold fat injection did not yield successful results.