Endoscopic otoplasty in the rabbit model: effect of mechanical abrasion on ear cartilage deformation.

Abstract

The purpose of this study was (1) to introduce an endoscopic technique for performing otoplasty; (2) to compare the durability of folding with scoring, sutures, or abrasion; and (3) to study the histologic changes associated with three techniques. Thirteen adult New Zealand White rabbits (26 ears) were divided into three otoplasty groups: bent cartilage (nine ears), cut cartilage (nine ears), or endoscopic abrasion of cartilage (eight ears). In all three groups, the ears were folded using external mattress sutures, with a transverse 180-degree fold. Sutures were removed at 1 to 6 weeks, and the ears followed for 4 weeks postoperatively. Ear-folding angles were followed weekly from suture removal to 4 weeks postoperatively. After sacrifice, the ear cartilage was harvested for histologic analysis. The ears were maintained in a 180-degree ventral fold by splinting sutures, which were removed at various times. Four weeks after suture removal, the mean ear angles were 13 degrees in the bent (control) group, 84 degrees in the cut group, and 132 degrees in the abraded group. The differences between the abraded and cut versus bent groups were significant (p = 0.0001 and 0.0073, respectively). There was no significant difference between the abraded versus cut groups. Histologic analysis showed perichondrial thickening on the convex surface in all of the groups. Fibrocartilage was produced in the cut and abraded groups. Based on histologic observation, the repair cartilage in the cut group was more fibrous, whereas that in the endoscopic group was more abundant with marked degenerative changes in the central zone. A new method of percutaneous endoscopic otoplasty in the rabbit model is described. This study showed that endoscopic otoplasty produced folding that was well maintained during the study period.