[Pediatric ureteral ureteral outlet obstruction and obstructive megaureter: observation or operation?].

Stenosis of the ureteropelvic junction and obstructive megaureter are still a diagnostic and therapeutic problems. So far, there is no reliable prognostic factor to predict the outcome of a primary dilated upper urinary tract under the "wait and see" strategy and to decide which child must be operated upon and which should not. In practice, basic diagnostic evaluation with sonography, possibly i.v.-pyelography and voiding cystography is accompanied by quantifying isotope-based procedures such as DMSA-uptake or diuretic renography. The Whitaker test has become less important. Based on the investigation by Koff et al., it seems to be possible to follow the "wait and see" procedure in more than 85% of the children without any loss of renal function of the dilated kidney.