Experimental study of ureteral free grafts. I. Surgical findings in transplanted and abandoned ureter.

OBJECTIVE

To develop two experimental models in rats to study the ureter under conditions of total devascularization and denervation.

METHODS

The ureter was autotransplanted as an integrated autologous free graft (IAFG) or abandoned in the retroperitoneum as a non integrated autologous free graft (NIAFG). Both models were compared with a normal group and a surgical control group. Sixty-two rats were randomly distributed: Normal ureter (NU) group (n = 20); surgical control, only ureterolysis (SC) group (n = 15); abandoned ureter as NIAFG (AU) group (n = 13); reimplanted ureter as IAFG (RU) group (n = 14).

RESULTS

SC group: in all cases a ureter with no alterations was observed although with slight periureteral fibrosis. AU group: some ureter specimens had a smaller caliber. Periureteral fibrosis was observed in all the cases. Vessel distribution was similar to that of the NU group. All the ureters conserved their lumen. 53.8% of the ureters showed spontaneous contractions and 100% contractions after mechanical stimulation. Cyst formation, necrosis, fistulas or stenosis of the lumen were not observed. RU group: microscopic findings of the ureter segment used as IAFG were compatible with those of a normal ureter. In all the cases a moderate degree of periureteral fibrosis was observed. In the majority of the cases a vascular framework of the fat immediately adjacent to the ureter was observed. In 13 of the 14 operated cases spontaneous contractions were observed. The ureteral segment used as IAFG showed no alterations in 10 cases and with alterations of various types in 4 cases. In 8 cases there was a greater or lesser degree of stenosis of the proximal suture.

CONCLUSIONS

The surgical findings and the macroscopic aspects of the four groups show the viability of the ureter free graft, IAFG as well as the NIAFG, in spite of the macroscopic changes.