Atrophy among Mucosa-Only versus Muscular Mucosa Superiorly Based Pharyngeal Flaps: A Pilot Animal Study

Abstract

Velopharyngeal insufficiency is frequently managed surgically via the superiorly based pharyngeal flap procedure. The flap used in this procedure traditionally consists of both mucosa and muscle. Although muscle is included to potentially increase survival and tissue bulk, its inclusion may result in postoperative dysfunction of pharyngeal sidewall motion. Although the benefits of pharyngeal flap surgery are established, the denervated muscular portion of the flap appears to atrophy. The purpose of this study was to evaluate whether a flap consisting entirely of mucosa provides the same tissue bulk as a conventional pharyngeal flap 12 weeks postoperatively. Ten laboratory-grade cats served as direct patient surrogates. Cats were randomized to undergo a superiorly based pharyngeal flap procedure with flaps composed of either both muscle and mucosa (n = 5) or mucosa only (n = 5). Blinded volumetric analysis was performed by three board-certified neuroradiologists using magnetic resonance imaging of the pharynx immediately after surgery and at 4, 8, and 12 weeks. At 12 weeks postoperatively, pharyngeal flaps composed of both mucosa and muscle atrophied to reach volumetric equivalence with mucosa-only flaps. Evaluation of final pharyngeal flap volume demonstrated no statistical differences between the two groups. This study demonstrates equivalent final superiorly based pharyngeal flap tissue bulk for flaps composed of only mucosa when compared with conventional pharyngeal flaps. Thus, the mucosa-only pharyngeal flap may yield similar outcomes while potentially providing for an earlier return of normal pharyngeal function.