The effect of indwelling duration of ureteral stent on the formation and pathological characteristics of ureteral stricture after holmium laser thermal injury.

Objective: A porcine model was established to investigate the effect of indwelling duration of ureteral stents on formation and pathological characteristics of ureteral stricture after laser thermal injury.

Methods: Pigs were randomly divided into 2 groups, A and B, with 15 pigs in each group. Holmium laser was used to cauterize the bilateral ureters at 5, 10, 15, and 20 cm from the Ureteropelvic Junction. Ureteral stents were indwelled for 4 weeks in Group A and 10 weeks in Group B. Ureteroscopy was performed 3 months after stents removal. Pigs were sacrificed to detect the damage point stricture. The cauterization tissue was harvested for pathological analysis.

Results: Group A included 13 pigs and group B included 14 pigs. The incidence of ureteral stricture in group A was higher than that in group B (P < 0.001). The percentages of inflammatory cell infiltration (P = 0.001), epithelial necrosis (P < 0.001), and epithelial hyperplasia (P < 0.001) were higher in Group A than in Group B. The proportion of muscle necrosis in Group A was lower than in Group B (P < 0.001). The percentage of the fibrosis area in group A was lower than that in group B (P = 0.001).

Conclusion: Compared with 4 weeks, 10 weeks of ureteral stent placement after laser thermal injury can reduce the risk of ureteral stricture, but may increase the risk of ureteral muscularis cell damage and tissue fibrosis. However, further clinical studies and animal experiments are required to confirm our results.