Combined Dorsal Plus Ventral Double Tunica Vaginalis Graft Urethroplasty: An Experimental Study in Rabbits

OBJECTIVE To investigate the efficacy of a combined dorsal plus ventral double tunica vaginalis graft for urethral reconstruction in a rabbit model through radiology and histopathology. METHODS Thirty adult male New Zealand rabbits were randomly divided into 6 groups as follows (n = 5): normal, stricture, and experimental groups A, B, C, and D. In the stricture and experimental groups, the ventral urethra was incised longitudinally, and the dorsal and ventral urethral mucosa were partially removed. Then, 3 x 20 mm and 5 x 20 mm tunica vaginalis grafts were obtained to repair the dorsal and ventral urethral mucosa defects, respectively, and the spongiosum was closed in the experimental groups. The urethral defects were not repaired in the stricture group. The rabbits in experimental groups A, B, C, and D were sacrificed at 2 weeks, 4 weeks, 12 weeks, and 24 weeks postoperatively, respectively, and the rabbits in the stricture group were sacrificed at 4 weeks postoperatively. The urethra was harvested for histological analysis. Urethrography was performed before sacrifice in the stricture group and experimental groups B and D. RESULTS The retrograde urethrogram showed that all rabbits in experimental groups B and D had a patent urethra. Histological examination showed that the tunica vaginalis graft completely integrated into the urethra at 4 weeks postoperatively and transformed into a urinary pseudostratified epithelium at 12 weeks postoperatively. CONCLUSION Combined dorsal plus ventral double tunica vaginalis graft urethroplasty is a feasible technique for urethral reconstruction in a rabbit model. (C) 2019 Elsevier Inc.