Previous studies showed controversial relative renal function (RRF) outcome after pyeloplasty in children. However, these studies had a small sample size. We aim at determining the status of RRF after pyeloplasty in children for a relatively larger number of patients in a tertiary referral center
After exclusion of patients with solitary kidney or bilateral pyeloplasty, we retrospectively identified 207 patients (˂18 years) who underwent pyeloplasty between January 2002 and January 2011 and to whom preoperative and postoperative renal scintigraphy (MAG3) available. Preoperative RRF was identified as low (<20%), moderate (20%-40%) and good (>40%). Postoperative RRF was defined as improved or deteriorated if it is 5% more or less than preoperative one, respectively. Preoperative and postoperative RRF were compared. Multivariate logistic regression analysis was performed to detect factors predictive of RRF deterioration.
Over a median followup period of 12 months (range: 6-93), the mean (SD) and median RRF was improved from 35.7% (10) and 37% to 37.9% (10) and 40% after pyeloplasty, respectively (P˂0.001). By repeated measure ANOVA, low and moderate RRF preoperatively showed improvement while good RRF showed a decline postoperatively (P˂0.001). On multivariate binary logistic regression analysis, preoperative low RRF (Referent is good RRF; OR: 0.2; 95%CI: 0.04-0.9; P=0.048), preoperative moderate RRF (Referent is good RRF; OR: 0.5; 95%CI: 0.2-0.9; P=0.028) and redo pyeloplasty (OR: 3.8; 95%CI: 1-13; P=0.035) were the only significant predictors for RRF deterioration.
RRF does improve after pyeloplasty in children. A lower preoperative RRF is more likely to improve after surgery. These findings are important in patients’ counselling prior to surgery, in addition, aim of the surgery should be directed at improving RRF.