Histological evaluation of an alternative method of neophalloplasty based on two lower abdominal skin flaps and simultaneous buccal mucosa graft in the ventral surface of the neophallus (two-stage urethroplasty): Experimental study in rabbits

Abstract 

Objective

To evaluate, in an experimental study in rabbits, a new model of neophalloplasty based on two lower abdominal skin flaps and ventral buccal mucosa graft for planned two-stage urethroplasty procedure.

Material and methods

Sixteen rabbits were operated and divided into four equal groups which were sacrificed at 2, 4, 8 and 12 weeks. The inflammatory pattern, presence of sub-epithelial fibrosis and epithelial changes in the grafted area were evaluated histologically.

Results

There were no deaths and no dehiscence of the wound was seen. One animal in the 2-week group developed an ulcer in the grafted area. We found minimal contracture of the neophallus, but this was not statistically significant between groups. Buccal mucosa graft showed good uptake in all groups, with vascular support from subcutaneous tissue of the flaps. The grafted area developed epithelial metaplasia, showing a decrease in cell layers with time, with disappearance of the sub-epithelial papillae and appearance of stratum granulosum and keratinization of the epithelial graft surface. A decrease in sub-epithelial fibrosis with replacement of immature by mature (eosinophilic) collagen was found. In the later groups was also observed an important decrease in inflammatory response, and the chorion of the grafted area presented a dilated capillary network, indicating that the process of neoangiogenesis was effective.

Conclusion

Buccal mucosa displayed histological integration in the abdominal flaps with epithelial metaplasia in all groups. The surgical aspect of the neophallus was cosmetically acceptable, with minimal contracture.

Keywords: Penile agenesis, Urethroplasty, Buccal mucosa, Lower urinary traxt, Penis