[Dilated upper urinary tract. Evaluation of the obstructive relevance of the ureteral junction by intrapelvic pressure-flow measurement (Whitaker test) in 23 children].

Twenty-three children with equivocal uretero pelvic junction (UPJ)-obstruction underwent antegrade pressure flow studies. In three of the twelve children with upper urinary tract dilatation without vesicorenal reflux UPJ-obstruction could be excluded. Voiding cystograms showed vesicorenal reflux in eleven of the children with reflux induced hydronephrosis in seven cases. The coexistence of UPJ-obstruction and vesicorenal reflux has been noted in four children. In 23 pressure flow studies there was only one equivocal result. Twelve kidneys said to be obstructed were operated and the diagnosis was confirmed. The uneventful follow-up in the other ten children confirms the diagnosis of hydronephrosis without obstruction. The overall accuracy rate of the Whitaker-test was 96%.