Urodynamic evaluation of results of endopyelotomy for ureteropelvic junction obstruction

We treated 13 patients with unilateral ureteropelvic junction obstruction by percutaneous endopyelotomy, and they were urodynamically evaluated by the Whitaker test and diuresis renography, in addition to excretory urography (IVP). Surgery was uncomplicated in all patients except 1 who required repeat incision 4 weeks later. Obstruction was diagnosed preoperatively by the Whitaker test and diuresis renography in 10 cases, and by IVP in 13. Postoperatively, all 10 patients (100%) with a positive Whitaker test were free of obstruction with a significant reduction in the relative renal pelvic pressure from 35.0 to 8.1 cm. water (p <0.01). Diuresis renography revealed no obstruction in 8 patients (80%) and persistent obstruction in 2. IVP demonstrated reduced hydronephrosis in 8 of 13 patients (62%) 12 weeks after surgery and in 11 of 13 patients (85%) 19 months later. However, a marked reduction in renal pelvic size was noted in only 3 patients (23%). Flank pain disappeared in 10 of 11 patients (91%) postoperatively. Overall, surgery was successful in 11 of the 13 patients (85%). Percutaneous endopyelotomy was effective in relieving obstruction at the ureteropelvic junction with minor morbidity. The Whitaker test was more sensitive for evaluating the results of surgery than diuresis renography and IVP, although diuresis renography appears to be useful in followup evaluation of hydronephrosis.