Purpose: Endopyelotomy has increasingly become well accepted as the optimal management for primary and secondary ureteropelvic junction obstruction. We report our experience with ureteroscopic endopyelotomy guided by endoluminal ultrasound.

Materials and Methods: Ureteroscopic endopyelotomy was attempted in 27 patients with primary and 10 with secondary ureteropelvic junction obstruction. Retrograde pyelogram and endoluminal ultrasound were performed at the start of the procedure in all patients. Based on sonographic findings 5 patients were not considered candidates for the procedure. The remaining 13 men and 19 women were treated ureteroscopically with a rigid ureteroscope in 5 (15.6%), flexible in 20 (62.5%), and rigid and flexible in 7 (21.9%) patients. Stents were placed postoperatively for 6 to 10 weeks. The patients were followed for a mean duration of 10 months.

Results: The procedure was completed in all patients. Average operating time was 95 minutes including the time for imaging. Sonographic localization guided the site of incision in all patients and changed therapy in 5. It identified crossing vessels in 10 patients (31%), septum denoting high insertion in 5 (15.5%) and both in 7 (22%). Preoperative stenting was not required in any patient. Morbidity was low with no patients requiring transfusion and no evidence of ureteral strictures. Success, defined as pain-free with resolution of obstruction on diuretic renal scan, was achieved in 28 of the 32 patients (87.5%).

Conclusions: Ureteroscopic endopyelotomy is a safe and effective treatment for most cases of ureteropelvic junction obstruction. Endoluminal ultrasonography of the obstructed ureteropelvic junction has gained a major role in defining which patient to treat and in directing endoluminal incisions to minimize the risk of injury to adjacent vessels. There is a higher failure rate when vessels are present.

Key words: ultrasonography, ureteral obstruction, ureter