Chronic expansion of the renal pelvis: a new method for reconstruction of upper ureteral defects

Abstract

Objectives. To evaluate whether the dilated renal pelvis can be used as an autologous source for the surgical reconstruction of upper ureteral defects or strictures. Methods. In 7 female pigs, the renal pelvis was expanded by a percutaneously placed Council balloon catheter. Every other day for 4 weeks, the renal pelvis was progressively dilated with a bolus injection of saline and contrast medium, which allowed expansion of the renal pelvis to 70 to 75 mL. Four to six weeks after the initial intervention, 5 to 7 cm of the proximal ureter was resected in an open operation and replaced with a tubularized spiral flap made from the expanded renal pelvis. Three weeks later, the animals were killed, and the area of manipulation was resected for pathologic evaluation. Results. All animals reached the desired expansion of the renal pelvis, and in all cases, the spiral flap was fashioned and anastomosed to the distal ureteral segment, bridging the initial defect (mean length 7 cm). Two animals died from sepsis, 4 and 6 days after the spiral flap reconstruction. A viable ureteral lumen with a patent anastomosis and a functioning pelvocaliceal unit was observed on intravenous urography in all animals. The main histologic findings were a chronic inflammatory process with concomitant mucinous metaplasia and reactive atypia of the tubules. Conclusions. The use of a balloon expander in the renal pelvis is a safe and effective technique for producing native tissue for the reconstruction of defects or strictures of the upper ureteral segment.