Tubularized urethral reconstruction using a prevascularized capsular tissue prelaminated with buccal mucosa graft in a rabbit model

Tubularized graft urethroplasty fails largely because of in adequate graft take. Prefabricati on of buccal mucosa lined flap has theoretical in dications for con structi ng neourethra with an in depe ndent blood supply. The efficacy of using a tissue expander capsule as an in duced vascular bed to prefabricate an axial vascularized buccal mucosa-lined flap for tubularized urethral rec on struction in a rabbit model was tested. The experiments were performed in three stages. First, silicone tissue expanders were inserted into the groin to induce vascularized capsule pouch formation. Next, buccal mucosa grafts were transplanted to the newly formed capsular tissue supplied by the axial vessel for buccal mucosa-lined flap prefabrication. Then, circumferential urethral defects were created and repaired by buccal mucosa graft (Group 1), capsule flap (Group 2) and prefabricated capsule buccal mucosa composite flap (Group 3). With retrograde urethrography, no rabbits in Group 1 maintained a wide urethral caliber. In Group 2, the discontinued epithelial layer rege nerated at 1 month, and the con structed n eourethra narrowed eve n though the lume n surface formed in tact urothelial cells at 3 months. In Group 3, buccal mucosa formed the lining in the neourethra and kept a wide urethral caliber for 3 mon ths. The capsule may serve as an in duced vascular bed for buccal mucosa-li ned flap prefabricati on. The prefabricated buccal mucosa-lined flap may serve as a neourethra flap for circumferential urethral replacement.