Ureteral regeneration in healthy and diseased ureter: an experimental and clinical study

ABSTRACT

To study ureteral regeneration after ureterotomy, an experimental study was done on 18 dogs where a segment 2 cm long including 2/3 of the circumference of the ureter was excised and the ureter was stented. Also, there was an opportunity to study ureteral regeneration in human ureter in four patients in whom endoscopic ureterotomy was unsuccessful and were surgically corrected by resection of the previously incised strictured segment. The specimens were histopathologically studied. In dogs, the healed segment of a normal ureter showed smooth muscle regeneration with variable degree of fibrous tissue. In human stenosed ureter, the strictured site showed a segmental scar consisting of connective tissue fibers, collagen fibers and few fibroblasts with no evident muscle fibers. The healthy tissue above and below the stricture site previously incised in the course of endoureterotomy showed regenerating smooth muscles. The clinical implication of this study is that endoureterotomy is not recommended in cases where the ureter is complete obstructed, fibrosed and there is no healthy muscles which will initiate a regeneration process