Keratinized versus non-keratinized preputial flap onlay urethroplasty: does it make any difference in the histological analysis? An experimental study in rabbits

Purpose To compare the histological characteristics of keratinized versus non-keratinized onlay island flaps in an experimental rabbit model. Materials and Methods Sixteen male rabbits were randomly allocated into two experimental groups: keratinized and non-keratinized onlay island flaps. A defect was created in the ventral aspect of the penile urethra. In the keratinized group, a longitudinal island flap was harvested from the external prepuce and rotated to cover the urethral defect. In the non-keratinized group a transverse island flap was harvested from the inner prepuce. The animals were sacrificed after 2, 4, 8 and 12 weeks. Results The flaps were viable in all animals, and no deaths were associated with the procedure. Two urethrocutaneous fistulas were identified, one in each experimental group. A similar pattern of fibrosis was identified in both groups. The keratinized epithelium of the external prepuce kept its histological aspect and keratin production. Both keratinized and non-keratinized groups presented a slight decrease on the epithelial thickness, however without a statistically significant difference between groups. Conclusions In this short-term rabbit model, we observed that the stratified squamous keratinized epithelium from the external prepuce kept its keratin production. There was no statistical influence of the flap type on the mean epithelial thickness. .

Keratinized versus non-keratinized preputial flap onlay urethroplasty: does it make any difference in the histological analysis? An experimental study in rabbits.

PURPOSE: To compare the histological characteristics of keratinized versus non-keratinized onlay island flaps in an experimental rabbit model. MATERIALS AND METHODS: Sixteen male rabbits were randomly allocated into two experimental groups: keratinized and non-keratinized onlay island flaps. A defect was created in the ventral aspect of the penile urethra. In the keratinized group, a longitudinal island flap was harvested from the external prepuce and rotated to cover the urethral defect. In the non-keratinized group a transverse island flap was harvested from the inner prepuce. The animals were sacrificed after 2, 4, 8 and 12 weeks. RESULTS: The flaps were viable in all animals, and no deaths were associated with the procedure. Two urethrocutaneous fistulas were identified, one in each experimental group. A similar pattern of fibrosis was identified in both groups. The keratinized epithelium of the external prepuce kept its histological aspect and keratin production. Both keratinized and non-keratinized groups presented a slight decrease on the epithelial thickness, however without a statistically significant difference between groups. CONCLUSIONS: In this short-term rabbit model, we observed that the stratified squamous keratinized epithelium from the external prepuce kept its keratin production. There was no statistical influence of the flap type on the mean epithelial thickness.

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.

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.