Use of diuretic renogram in evaluation of patients before and after endopyelotomy

Objectives. Endopyelotomy is a widely accepted alternative in the treatment of ureteropelvic junction (UPJ) obstruction, with success rates between 63 % and 88%. However, various methods have been used to evaluate patients wit h UPJ obstruction, making it difficult to compare results. Diuretic renogra phy has the potential to unify the evaluation if performed in standard ways . In this report, we present a standardized protocol for diuretic renograph y. Methods. Nineteen endopyelotomies were performed by one surgeon (E.B.K.) at our institution. The 16 patients were evaluated with technetium 99m MAG-3 diuretic renography. The presence or absence of obstruction was classified according to the differential renal function, time activity curves, and T-m ax to T-1/2max time. Three patients had a postoperative Whitaker's test. Results. Eight patients had pre- and postoperative diuretic renograms at ou r institution. This group was stratified by their differential renal functi on. Among 4 patients with differential renal function greater than 35%, 3 o f 4 showed progressive improvement in renal function postoperatively, 4 of 4 had a T-max to T-1/2max time less than 10 minutes, and 3 of 4 had unobstr ucted time activity curves. Five patients had postoperative renograms only. Of these 5 patients, 4 had differential renal function greater than 35% an d 5 of 5 had normal-appearing curves and normal T-max to T-1/2max time. Thr ee patients required a second endopyelotomy and 2 of these underwent a dism embered pyeloplasty. Conclusions. Standardized diuretic renography should be used as an objectiv e test for the evaluation of patients with UPJ obstruction. The successful outcome of an endopyelotomy depends on the preoperative renal function of t he involved kidney. Whitaker's test may be used for equivocal cases. (C) 19 99, Elsevier Science Inc. All rights reserved.