A Novel Experimental Method for Penile Augmentation Urethroplasty With a Combination of Buccal Mucosa and Amniotic Membrane in a Rabbit Model

To investigate the results of penile urethral reconstruction using amniotic membrane (AM) and buccal mucosa (BM) grafts, and the simultaneous use of both in a rabbit model.

A total of 28 male rabbits were divided into 4 groups according to grafting style: group 1 (AM), group 2 (BM), group 3 (BM + AM), and group 4 (sham). A standardized urethral defect was created in the 3 initial groups. The sham group underwent only a ventral vertical urethral incision and primary re-suturation. AM grafts were used in group 1, and BM grafts were used in groups 2 and 3. AM grafts were affixed to the BM grafts in group 3 as a covering tissue. Urethrography and endoscopy were performed after the 1st and 2nd months of grafting. The penises were subjected to histopathologic and immunohistochemical assessment for fibroblast growth factor and vascular endothelial growth factor expression.

Dehiscence and fistula developed in group 1, whereas 2 fistulas were observed in group 2. No complications developed in group 3. Epithelization at urethras was observed at 4 weeks in all groups, but transformation to urothelial epithelialization occurred at 8 weeks. Marked amelioration and epithelial transformation were observed in group 3. The most prominent fibroblast growth factor expression was observed in group 3. Vascular endothelial growth factor expression was completely negative in group 3 at 8 weeks, indicating complete healing.

The simultaneous use of AM and BM for ventral onlay penile urethroplasty provides better tissue healing and lower complication rates in comparison to BM alone. Further animal studies or clinical applications are needed.