Distal ureteral diameter measurement objectively predicts vesicoureteral reflux outcome

Objective: Vesicoureteral reflux (VUR) grading may be difficult when discrepancies exist between the degree of dilation of the pyelocalyceal system and the ureter. Resolution may be more accurately predicted by the appearance of the distal ureter. We analyzed a novel, objective method of evaluating VUR based on the diameter of the distal ureter. Methods: Seventy-nine voiding cystourethrograms were reviewed (18 boys; 61 girls; aged 1 month to 7.5 years). The largest ureteral diameter within the false pelvis was measured and normalized by dividing by the distance from the L1-L3 vertebral body to give the distal ureteral diameter: L1-L3 ratio (UDR). Clinical outcome was defined as spontaneous resolution or surgical correction. Results: A significant association between grade and UDR existed (p < 0.0001). Mean UDR was significantly greater in those who underwent surgical correction (0.34 ± 0.02 vs 0.18 ± 0.02; p < 0.0001). Logistic regression analysis demonstrated a significant association of UDR with outcome controlling for grade (p = 0.001). Grade effect on outcome when controlling for UDR was not significant (p = 0.76). Odds ratio for surgical correction corresponding to a 0.1 increase in UDR equaled 2.25 (95% CI: 1.39, 3.64). Conclusion: UDR provides an objective measurement of VUR and appears more predictive of clinical outcome than grade in this series.