Healing process in the ureter: an experimental study in dogs

Objective: This study set out to describe the basic milestones in the pattern of healing in the ureter in order to understand why problems in healing arise when the ureter is severed, usually through anastomotic leakage or stricture formation. Method: Transection and anastomosis of the ureter were performed on dogs. The anastomotic segment was removed at days 6, 14, 21 and 42. Mucopolysaccharide levels, collagen content and breaking strength were measured on these samples and on anatomically similar segments from normal dogs. A minimum of five observations were carried out at each time point. The mean values of the estimations in various groups were compared. Differences were considered significant at p≤0.05. Results: Mucopolysaccharide levels peaked at day 6 and then fell gradually to near normal (p>0.05) by day 42. The collagen content rose to a maximum at day 14 and then fell to near normal levels (p>0.05) by day 21. Breaking strength rose gradually to peak by day 21 and then fell to reach day 6 level (>0.05) at day 42. At no time point did it reach anywhere near normal value. Full healing in the ureter takes at least six weeks. Conclusion: The healing process in the injured ureter is different to that in other tissues. It is probable that clues to anastomotic healing problems of the ureter lie in the paradoxical pattern of collagen formation. Declaration of interest: None.