Percutaneous surgery for ureteropelvic junction obstruction (endopyelotomy): technique and early results.

We incised ureteropelvic junction obstruction in 31 patients with a cold knife direct-vision urethrotome inserted through a percutaneous nephrostomy tract. In 12 patients renal calculi were removed endourologically during the same session. There were no immediate complications and nephrostograms showed adequate drainage in all cases. Of these patients 8 had previously undergone open pyeloplasty without success. The longest followup is almost 2 years. There have been 4 failures and, thus, the success rate is 87.1 per cent.