Delayed redo pyeloplasty fails to recover lost renal function after failed pyeloplasty: Early sonographic changes that correlate with a loss of differential renal function

PURPOSE: To evaluate changes in differential renal function (DRF), as a functional outcome, in children who underwent redo pyeloplasty for management of failed pyeloplasty and to examine the factors that affect functional outcomes. MATERIALS AND METHODS: Between January 2002 and November 2010, a total of 18 patients who underwent redo pyeloplasty for persistent ureteropelvic junction obstruction after failed pyeloplasty were enrolled in this study. We assessed perioperative factors and evaluated changes in renal cortical thickness (RCT), renal function, and hydronephrosis by use of serial ultrasound and diuretic renography. RESULTS: The mean follow-up period was 44.83±28.86 months. After redo pyeloplasty, prevention of further functional deterioration was observed in only 12 of the 18 patients. After dividing the patients according to this observation, we discovered significant differences in both change in DRF (dDRF) and change in RCT (dRCT) (difference between before and after initial pyeloplasty) between the two groups (p<0.001). Additionally, we noted a significant positive correlation between dRCT and dDRF. All patients showed improvements in hydronephrosis grade and relief of symptoms compared with before redo pyeloplasty. CONCLUSIONS: Redo pyeloplasty should be considered in cases of failed pyeloplasty to preserve renal function and obtain relief from symptoms. If patients show severe deterioration of DRF or a decrease in RCT after initial pyeloplasty, preservation of DRF in these patients after redo pyeloplasty could be difficult. Therefore, redo pyeloplasty should be performed before severe deterioration of DRF or decrease in RCT.