Dynamic hydrodistention of the ureteral orifice: a novel grading system with high interobserver concordance and correlation with vesicoureteral reflux grade.

Purpose: We evaluated the usefulness and interobserver concordance of a novel grading system for dynamic ureteral hydrodistention.

Materials And Methods: Between May 1, 2002 and July 1, 2008 the hydrodistention grade in 697 ureters was prospectively assigned and recorded, including H0-no hydrodistention, H1-ureteral orifice open but tunnel not evident, H2-tunnel seen only and H3-extravesical ureter visualized. Specifically 489 refluxing ureters (vesicoureteral reflux group) were compared to 100 normal control ureters (normal control group). Additionally, the posttreatment hydrodistention grade in 56 ureters in which surgery for reflux failed was compared to that in 52 ureters with successful surgery. Hydrodistention grades assigned to an additional 77 ureters by 3 blinded observers were compared to assess the interobserver concordance of this system.

Results: Vesicoureteral reflux and hydrodistention grades correlated significantly (p <0.001). Ureters with a higher reflux grade also showed a higher hydrodistention grade. The normal control group (mean +/- SEM hydrodistention grade 0.62 +/- 0.07) showed a statistically lower hydrodistention grade than the reflux groups (overall mean hydrodistention grade 2.26 +/- 0.01). Mean posttreatment hydrodistention grade in the failed reflux surgery group was statistically higher than that in the mean successful reflux surgery group (2.03 +/- 0.09 vs 1.33 +/- 0.08). By defining the degree of hydrodistention as normal (H0-H1) and abnormal (H2-H3) the concordance between observers was 95% and 96%.

Conclusions: The dynamic hydrodistention classification is a reliable method of evaluating the presence or absence of vesicoureteral reflux as it correlates significantly with radiographic reflux grade. It has high interobserver concordance.