Conservative treatment of ureteropelvic junction obstruction in children with antenatal diagnosis of hydronephrosis: lessons learned after 16 years of follow-up.

OBJECTIVES

We attempted to define predictive factors for surgery in children with antenatal diagnosis of hydronephrosis that led to postnatal diagnosis of ureteropelvic junction (UPJ) obstruction.

METHODS

We retrospectively evaluated our 16-yr experience (1988-2003) with 343 children (260 male and 83 female) with antenatal diagnosis of hydronephrosis that led to postnatal diagnosis of UPJ obstruction and who were followed conservatively. Right-sided hydronephrosis was present in 110 and left-sided in 233 children. According to the Society for Fetal Urology (SFU) classification none had grade 0 of postnatal hydronephrosis, 20 had grade 1, 118 grade 2, 147 grade 3, and the remaining 58 children grade 4 postnatal hydronephrosis. Relative renal function (RRF) on radionuclide scans revealed 235 children with RRF>40%, 68 with RRF between 30% and 40%, and 40 patients with RRF<30%. Renal function deterioration >5% was the main indication for surgery. Commercially available software GraphPad Prism 4.0 (GraphPad prism, Prism 4 for Windows, version 4) using the Fisher exact test was used for statistical evaluation.

RESULTS

Surgical correction was needed in 179 children (52.2%) during the course of conservative management. The average age at surgery was 10.6 mo (range, 1 mo to 7 yr). Of those, 50% underwent surgery during the first 2 yr of life and the majority of the remaining patients underwent surgery between the 2 and 4 yr of age; only two patients required surgery later on. Univariate analysis revealed that child sex, side of hydronephrosis, and SFU grade of prenatal hydronephrosis were not significant predictive factors for surgery. However, SFU grade 3-4 of postnatal hydronephrosis (p<0.0001; odds ratio, 0.06281) and RRF<40% (p<0.0001; odds ratio, 0.1022) were significant independent risk factors for surgery.

CONCLUSION

In contrast with previous publications by others and by us these data show that >50% of children with antenatal diagnosis of UPJ obstruction in this series required surgical correction while on conservative protocol. SFU grade 3-4 of postnatal hydronephrosis and RRF<40% are significant independent predictive factors for surgery.