Validation of Onen's Alternative Grading System for Congenital Hydronephrosis

Woo, Da Eun; Lim, Myung Hee; Kim, Myung Uk; Kim, Sae Yoon; Park, Yong Hoon

Abstract

PURPOSE
The purpose of this study was to compare the validity of Onen's alternative grading system (AGS) with that of the APDRP and SFU grading systems in patients with isolated and complicated congenital hydronephrosis.
METHODS
We retrospectively reviewed the medical records of 153 patients (204 renal units) diagnosed with congenital hydronephrosis between January 2002 and December 2011. We classified patients into 2 groups; isolated or complicated hydronephrosis. All renal units were graded according to anterior-posterior diameter of renal pelvis (APDRP), Society for Fetus Urology (SFU) and Onen's grading systems. We analyzed the prognosis of hydronephrosis, according to each grading system, at 2 years of age.
RESULTS
There were 152 renal units with isolated hydronephrosis and 52 renal units with complicated hydronephrosis. The isolated hydronephrosis group had a lower grade according to Onen's AGS, and showed more frequent spontaneous remission by 2 years of age. There was more frequent obstruction (P=0.000) and surgical treatment (P=0.000) of units with high-grade hydronephrosis according to Onen's AGS. In the complicated hydronephrosis group the frequencies of spontaneous remission (P=0.015) and renal dysfunction (P=0.013) were significantly higher than those in high-grade hydronephrosis, as indicated by Onen's AGS. There were no significant differences in clinical outcomes among the highest grade groups, according to the 3 systems, in either isolated or complicated hydronephrosis.
CONCLUSION
Onen's AGS reflects the prognosis of hydronephrosis as well as other grading systems in those with isolated hydronephrosis. It was better predictor of renal dysfunction in those with complicated hydronephrosis. However, Onen's AGS was not superior to the other grading systems in terms of predicting prognosis, especially in high-grade hydronephrosis.