The Value of Estimation of Distal Ureteral Dilatation in Primary Vesicoureteral Reflux

PURPOSE Recently, several studies have suggested that distal ureteral dilatation is an important factor influencing the spontaneous resolution of primary vesicoureteral reflux (VUR). We evaluated the relationship between distal ureteral dilatation and the spontaneous resolution of primary VUR. MATERIALS AND METHODS The medical records of 114 patients with primary VUR maintained on prophylactic antibiotics from April 1999 to August 2008 were retrospectively reviewed. The patients' mean age was 24.2 months (range, 6-108 months). There were 66 male patients and 48 female patients. The mean follow-up was 37.6 months (range, 12-102 months). We analyzed various factors including age, gender, grade of reflux, laterality, and ureteral diameter ratio (UDR; the largest ureteral diameter was divided by the distance from the L1-4 vertebral body to minimize the differences in diameter by age) to determine whether these factors influenced the spontaneous resolution of primary VUR. RESULTS Unilateral, low-grade reflux and low UDR were significantly associated with the spontaneous resolution of reflux (p=0.048, p<0.001, and p<0.001, respectively). The multivariate analysis revealed that the spontaneous resolution rate of primary reflux was significantly higher in patients with low UDR than in patients with high UDR (p<0.001). CONCLUSIONS The degree of distal ureteral dilatation is expected to be another important factor in determining therapeutic course and predicting the spontaneous resolution of VUR.