Histomorphometric study of experimental extramucosal ureteroureterostomy.

The reconstruction of the urinary tract is still nowadays a controversial issue. This study is based on the use of histomorphometric techniques to describe the changes which take place in extramucosal ureteroureterostomy. A medial laparotomy was performed in 41 Wistar rats. The left ureter was sectioned and an extramucosal anastomosis was performed. All rats were sacrificed 25 days postsurgery. Histomorphometric studies were performed on the sutured ureters as well as on the contralateral (unrepaired) ureters. Two of the 41 cases operated died. Five others developed hydronephrosis and/or urinary fistula. Histomorphometric studies gave an average cross-sectional area of 98,662.5 +/- 31,927 mu 2 for the anastomosed ureters versus 75,176.3 +/- 16,732.4 mu 2 for the control ureters (P less than or equal to 0.01). Sutured ureters showed an increase in the area of the muscular layer (P less than or equal to 0.001) and the submucosa (P less than or equal to 0.01) compared with control ureters. Mucosa and lumen areas showed no significant differences between the groups. Sectioned ureters show an increase in total area and width based on a hypertrophy of the muscular and submucosal layers.