Early diuresis renogram findings predict success following pyeloplasty

We sought to determine whether drainage across the ureteropelvic junction, as indicated by diuretic renography 3 months after pyeloplasty, is an adequate predictor of surgical success.

The medical records of 150 children who underwent pyeloplasty from 1986 to 1995 were reviewed. After excluding nonevaluable cases a total of 127 renal units remained for investigation. Preoperatively each renal unit was examined with a standardized (well-tempered) furosemide stimulated renal scan. Postoperatively 60 renal units were evaluated with standardized diuretic renal scans at 3 and 12 months, 33 renal units at 3 months only and 34 renal units at 12 months only. Surgical success was defined by half-time less than 20 minutes on a standardized diuretic renogram.

Of the 33 renal units with a single postoperative study at 3 months 32 (97%) had halftime less than 20 minutes on diuretic renography. The remaining patient in this group with half-time greater than 20 minutes showed 60% improvement in half-time and did not require reoperation. Excluding those without delayed followup, surgical success was obtained in 93 of the 94 (99%) renal units. Among the 60 renal units evaluated with 2 postoperative renal scans success was noted in 48 (80%) and 59 (98%) at 3 and 12 months, respectively. Stenosis did not recur in 48 renal units with half-time less than 20 minutes 3 months after repair. In 1 case that had been treated for postoperative urinoma half-time was greater than 40 minutes at 3 months and repeat pyeloplasty was required.

Half-time less than 20 minutes 3 months after pyeloplasty predicts surgical success. Most renal units that improve but still have half-times greater than 20 minutes on an early diuretic renogram will demonstrate continued improvement in drainage patterns at 12 months. Those renal units that show no improvement at 3 months may require reoperation and those with half-time less than 20 minutes at 3 months do not require further evaluation.