VASCULAR ANATOMY AT THE URETEROPELVIC JUNCTION

In 65% of the cases regarding the ventral surface of the UPJ, there wa s a prominent artery, vein, or both in close relation to the ventral s urface of the UPJ. In only 6.8% there was an inferior polar artery cro ssing anteriorly to the UPJ. Therefore, many of the vessels visualized close to the UPJ and described as anomalous and etiologic in obstruct ion are normal segmental arteries that do not cause UPJ obstruction. I n 26.7% of cases regarding the dorsal surface of the UPJ, there was a vessel crossing at or lower than 1.5 cm above the posterior surface of the UPJ. On the basis of our anatomic findings, we advise that in end opyelotomy, the incision along the stenotic UPJ be created only at its lateral aspect.