Treatment of large impacted proximal ureteral stones: randomized comparison of percutaneous antegrade ureterolithotripsy versus retrograde ureterolithotripsy.

Percutaneous antegrade ureterolithotripsy is a valuable treatment modality for impacted proximal ureTERal calculi larger than 1 cm, and achieves higher stone-free rates than those of retrograde u reteroscopy with holmium:YAG laser lithotrips.