Influence of hip flexion on the course of the ureter. Ureteroscopic implications.

Early experience with the rigid ureteroscopy has identified two regions of the ureter that can be difficult to negotiate, the first at the vesicoureteric junction and the second anterior to the iliac bifurcation. Placing the patient in varying degrees of lithotomy has been proposed to overcome these problems. In this study the effects of these alterations of hip flexion on the course of the ureter have been studied by radiographs in patients undergoing ureteroscopy. The lower ureter was demonstrated to possess two curves, an upper curve at the iliac bifurcation which straightens with increasing degrees of lithotomy and a lower vesical curve in the pelvis which is unaltered by patient position. These findings and their clinical significance are described.