Fig. 1

The improved prone frog split-leg position. After preset the flexible ureteroscope sheath into the target ureter in the traditional lithotomy position, turn to prone position, at the same time, bend both hips and knees to be frog abduction, which should not exceed the physiological curvature. The soft postural support pad should be placed on the front wall of both thighs to prevent hanging, and the lower legs should be fixed with a fixing strap