Autologous Fat Graft Absorption in Unilateral Paralyzed Canine Vocal Folds

Abstract

The objective of this experimental prospective study on an animal model was to determine the rate of autologous fat graft absorption in 24 paralyzed canine left vocal folds 12 weeks after introduction. Forty mongrel dogs of both sexes weighing 15 to 20 kg were divided into three study groups (SGs) of eight dogs each whose larynges were grafted by vocal fold lipoinjection (VFL-SGA), vocal fold lipoinjection plus insulin (VFLi-SGB), and by fat graft medialization laryngoplasty (FGML-SGC) and observed for 12 weeks. Two control groups (CGs) of eight dogs each were submitted to fat graft medialization laryngoplasty (FGML-CG1) and by vocal fold lipoinjection (VFL-CG2), respectively, followed by immediate killing. All 40 dogs were submitted to left vagal and recurrent laryngeal nerve resection. All animals were confirmed to have a left vocal fold paralysis 4 weeks later when 2 mL of autologous fat graft was placed inside the left paraglottic space. The larynges were removed at preestablished times and studied for remaining fat graft volume by magnetic resonance imaging. The mean volume obtained by imaging were 1.9388 mL for CG1, 1.0476 mL for CG2, 0.1924 mL for VFL, 0.336 mL for VFLi, and 0.565 mL for FGML. CG1 and CG2 did not differ significantly from one another but differed from the SGs, with statistical analysis suggesting a lower absorption of the fat graft in FGML. The absorption rate was 82% in SGA, 68% in the SGB, and 71% in SGC.