Ureteropelvic junction stenosis: vascular anatomical background for endopyelotomy.

To help endourologists perform endopyelotomy safely and efficiently with a reduced risk of vascular complications, we analyzed the vascular relationships to the ureteropelvic junction in 146, 3-dimensional endocasts of the kidney collecting system together with the intrarenal arteries and veins. There was a close relationship between a prominent vessel (artery and/or vein) and the anterior surface of the ureteropelvic junction in 65.1% of the cases, including the inferior segmental artery with a tributary of the renal vein in 45.2% and an artery or vein in 19.9%. In the remaining 34.9% of the cases the anterior surface of the ureteropelvic junction was free of vessels. There was a direct relationship between a prominent vessel (artery and/or vein) and the posterior surface of the ureteropelvic junction in 6.2% of the cases, including an artery and vein in 2.1%, and just an artery in 1.4%. In all cases (3.5%) of an artery crossing at the posterior surface of the ureteropelvic junction, this vessel was the posterior segmental artery (retropelvic artery). In 2.7% of the cases the relationship of the prominent vessel was just with a posterior tributary of the renal vein, and in 20.5% a vessel crossed lower than 1.5 cm. above the posterior surface of the ureteropelvic junction. Among these latter cases the vessel was an artery (posterior segmental artery) in 6.8%. In the remaining 73.3% of the cases the posterior surface was free of vessels up to 1.5 cm. above the ureteropelvic junction. Due to the anatomical findings, we advise that posterior and posterolateral incisions at the ureteropelvic junction be avoided, and that deep incision alongside the ureteropelvic junction stenotic wall be done only laterally.