(P23) collagen fleece grafting of the tunica albuginea in animal models: does size matter?

Abstract Background Collagen fleece (TachoSil) has been used clinically to repair penile tunica albuginea defects, especially in Peyronie’s disease and penile prosthesis surgery, though its benefits remain debated. This study assesses its efficacy in rat and canine models. This study’s objective was to assess the histopathological impact of TachoSil grafting on the tunica albuginea and underlying cavernous tissue and to evaluate the long-term hemodynamic effects of this intervention. Methods Seven rats and two dogs were studied. In rats, a 1x10 mm tunica albuginea defect was grafted with TachoSil and examined histopathologically after two months. In dogs, a 0.5x1 cm defect was made on one side of the penis, with multiple 1 cm incisions on the other. Intracavernous pressure (ICP) was measured before grafting and six months after, following papaverine injection (10 mg). The Wilcoxon Signed-Rank Test compared pre- and post-grafting ICP. The dogs were euthanized after six months for histopathological analysis. Results All seven rats survived until the study endpoint. Histopathological analysis revealed no regeneration of the tunica albuginea, though the underlying cavernous tissue remained protected from subcutaneous infection. In contrast, the canine model demonstrated complete regeneration of the tunica albuginea, with newly formed tissue indistinguishable from adjacent normal tunica. Hemodynamic analysis in dogs showed no significant difference in ICP response to papaverine before grafting (113 ± 31.1 mmHg) versus after grafting (122 ± 26.1 mmHg, P = 0.465). The observed discrepancy in tunica albuginea regeneration between species may be attributed to differences in grafting duration and the relative size of the tunica defect to penile size. Conclusion When used to repair defects, TachoSil appears to facilitate full regeneration of the tunica albuginea. However, the success of this technique may depend significantly on factors such as defect size and the duration of grafting.