To determine, in children with antenatally detected pelviureteric junction (PUJ) stenosis, what factors may be predictive for deterioration of differential renal function (DRF) in case of conservative treatment or improvement of DRF in case of pyeloplasty.

This study analyzed and compared the initial level of hydronephrosis, DRF, quality of renal drainage, and cortical transit with the late DRF outcome. We reviewed the medical charts of 161 consecutive children with antenatally diagnosed PUJ stenosis during a 10-year period (between 1997 and 2007). From this cohort, we retained 81 children with unilateral PUJ and strictly normal contralateral kidney, with a median follow-up of 67 months. Repeated ultrasounds, voiding cystourethrography, and radionuclide renograms were performed in all children.

Fifty patients never underwent a surgical intervention (62%), whereas surgical repair (Anderson-Hynes dismembered pyeloplasty) was performed in 31 (38%). During conservative follow-up, DRF deterioration was observed in 11% of patients. After pyeloplasty, DRF improvement was observed in 25% of patients. Abnormal cortical transit was the only predictive factor of DRF deterioration in case of conservative approach, whereas the initial degree of hydronephrosis, or renal drainage, and the initial DRF level were not predictive. In children who were operated on, only impaired cortical transit was predictive of DRF improvement postoperatively.

Conservative management of children with unilateral PUJ stenosis is a safe procedure. Impaired cortical transit although imperfect, seems the best criterion for identifying children for whom pyeloplasty is warranted.