Crossing vessels - Endourologic implications

The controversy regarding the functional significance of vessels crossing at the ureteropelvic junction is not a new one, though this debate has been resurrected in recent years because of application of endourologic techniques to manage ureteropelvic junction (UPJ) obstruction. The principle limitation of endoscopic treatment of UPJ obstruction is the inferior success rate compared to open dismembered pyeloplasty. The influence crossing vessels may have in affecting both the success rates and complications of endoscopic treatment of UPJ obstruction has yet to be resolved. Crossing vessels may be important for two reasons: (1) they are a potential source of hemorrhage following endoscopic incision, and (2) they may play an etiologic role in UPJ obstruction and therefore may be a reason for failure of endoscopic techniques. This article reviews some of the historical aspects of crossing vessels and explores recent studies that are starting to shed some light on this controversial topic.