Comparison of Mesothelial and Anti-mesothelial Surfaces of Tunica Vaginalis Flap as an Intermediate Layer in Urethroplasty: An Experimental Histopathological Study

Objective: Intermediate layers are commonly used to support the suture line in urethroplasty, with tunica vaginalis (TV) being one such option. However, it remains unclear which surface of the TV flap (TVF) is optimal for placement over the urethra. This study aimed to evaluate the effect of different TVF surfaces on urethral healing in an experimental model.

Methods: Urethroplasty was performed on 24 adult male Wistar-albino rats, which were randomly assigned to 3 groups: control (urethroplasty only), mesothelial (mesothelial surface of TVF over urethra), and anti-mesothelial (anti-mesothelial surface over urethra). On postoperative day 21, urethral tissues were harvested and analyzed histopathologically using hematoxylin–eosin, Masson’s trichrome, and anti-alpha smooth muscle actin staining to assess inflammation, fibrosis, and neovascularization.

Results: Inflammation scores did not differ significantly among the 3 groups (P = .163). Fibrosis scores differed significantly overall (P = .030). Pairwise comparisons demonstrated significantly higher fibrosis scores in the anti-mesothelial group than in the control group (P = .006) and the mesothelial group (P = .027). Fibrosis scores were also significantly higher in the mesothelial group than in the control group (P = .025). Neovascularization was significantly greater in the anti-mesothelial group than in the mesothelial group (P = .046). Neovascularization was not evaluated in the control group because no interposed tissue was used during urethroplasty.

Conclusion: The orientation of the TVF may influence histopathological healing following experimental urethroplasty. While flap orientation was not associated with significant differences in inflammation, the anti-mesothelial orientation was associated with greater fibrosis and increased neovascularization than the mesothelial orientation. These findings should be interpreted cautiously because they are based on histopathological outcomes in an experimental model.

Cite this article as: Şentürk M, Deliağa H, Özçakır E, et al. Comparison of mesothelial and anti-mesothelial surfaces of tunica vaginalis flap as an intermediate layer in urethroplasty: an experimental histopathological study. Urol Res Pract. 2026; 52, doi:10.5152/tud.2026.25120