Effect of stent duration on ureteral healing following endoureterotomy in an animal model.

Ureteral strictures were created in 18 minipigs. Six weeks after stricture inducement, endourologic incision with a balloon cutting device was performed and a 7 F internal polyurethane stent was placed. After this step, 14 pigs remained in the study and were randomized into three different groups depending upon the time when the stent was removed: 1, 3 or 6 weeks. Twelve weeks after stricture incision, the pigs were killed, the status of the incised ureteral segment was evaluated histologically, and a healing score was determined. There were no statistically significant overall differences among the mean values of the overall healing score throughout the three different groups. However, when the one-week and the six-week groups (p < .05) were compared with respect to strictures requiring more than one incision due to stricture length greater than 2 centimeters, a more favorable outcome occurred in the 1 week group. Based on these findings it may be reasonable to remove ureteral stents as early as 1 week after endoureterotomy and endopyelotomy.