Comparison of Full-Thickness Bladder Tissue Effects in Onlay versus Tubular Ureteral Reconstruction: A Study in a New Zealand Rabbit Model

Objective To explored the use of full-thickness bladder as a novel autologous material and comparing its efficacy in Onlay Reconstruction versus Tubularized Reconstruction. Approximately 75% of benign ureteral strictures are iatrogenic. Even without complete disruption of ureteral continuity, these strictures can cause many complications. Current, reconstruction is favored for its durable outcomes, its application lacks a standardized consensus due to limitations in graft materials and surgery. Methods Using 2.5 kg New Zealand rabbits, we reconstructed 1.5 cm and 2.5 cm ureteral stricture segments. Postoperative ureterograms assessed urinary leakage. Reconstructed areas were evaluated for morphological changes and fibrosis using HE and Masson staining. Results No postoperative urinary leakage occurred in any rabbits, and all remained healthy during the 6-week observation. The tubularized and 1.5 cm Onlay reconstructions healed well, but a diverticulum developed in the 2.5 cm Onlay area. HE staining revealed good vascular distribution in all reconstructed sites, though urothelial cells were not fully preserved in the Onlay reconstruction areas. Masson staining indicated varying fibrosis levels, with the Onlay area exhibiting the most severe fibrosis, which increased with longer repair lengths. Conclusion Full-thickness bladder wall is a safe, effective autologous graft material with less postoperative complications. Both tubularized and Onlay reconstruction effectively achieve ureteral reconstruction.