Objectives. During the past 10 years, numerous reports around the world have documented the safety and success rate of antegrade endopyelotomy. We describe the classic endopyelotomy in conjunction with some new alternatives for making the incision.

Technical Considerations. Antegrade endopyelotomy is performed through the 0.5-in. incision of the percutaneous nephrostomy created by way of an upper or middle calix. Using the hook-shaped cold knife, an endopyelotome is positioned, and the entire procedure can be performed under direct vision, which determines the exact position, depth, and extent of the incision. The ureteropelvic junction (UPJ) obstruction is incised in a posterolateral position, and the hook is withdrawn from the proximal ureter. Using nephroscopic scissors, a small full-thickness puncture is made into the renal pelvis and then the scissors is opened, under constant visual control, until it reaches the peripelvic space. The section of the pelvic wall is completed with the scissors running through the UPJ, without any interchange of the nephroscope. A holmium laser has been also used, with the 365-μm fiber introduced through a stent-pusher. Under direct vision, the UPJ is incised with fiber, permitting observation and coagulation of bleeding from small vessels. After the procedure, either a 14-8.2F endopyelotomy stent or a 14-7F tapered endoureterotomy stent is placed over the guidewire.

Conclusions. Percutaneous antegrade endopyelotomy is a safe and effective treatment of UPJ obstruction for most patients, regardless of the method used to perform the incision.