Outcome of apparent ureteropelvic junction obstruction identified by investigation of fetal hydronephrosis.

Objectives: The purpose of the study was toevaluate the outcome of prenatally detectedureteropelvic junction obstruction (UPJO)managed with a more conservative protocol.Methods: The records and imaging studies of 77consecutive neonates with UPJO identified by fetal hydronephrosis werereviewed. A nonoperative approach wasattempted in patients with mild/moderate pelvicdilatation, renal units with good functionas ascertained by DMSA scan and anon-obstructed pattern on DTPA. Otherwise, thepatients were managed surgically bypyeloplasty. Both groups were prospectivelyfollowed and the imaging studies were performedbefore and after the initial approachand at one-year intervals thereafter.Results: Of the 77 infants (85 units), 39 weresubmitted to surgery (33 pyeloplasty and 7 nephrectomy) and 38 were conservativelymanaged. During follow-up, 9 (24%) of 38 patients in the non-operative group presentedrenal function deterioration and 3 presented with urinary infections and were submitted topyeloplasty. Of the 39 patients surgically managed, 76% presented improvement ofhydronephrosis and 90% showed a non-obstructed pattern on diuretic renography. Thedifferential renal uptake, as measured by DMSA scan, remained stable in the three groupsanalyzed (conservative, initial pyeloplasty, and delayed pyeloplasty). Therewas a minimal improvement in those units submitted to pyeloplasty with impairedrenal function at baseline (< 40%). Mean renal uptake was 28.6% at admission and33.9% at the end of follow-up. Conclusion: There was a wide spectrum ofureteropelvic junction stenosis. Surgical intervention in a subgroup of patients withsevere hydronephrosis and impaired function may possibly improve or preserve renalparenchyma. Conversely, conservative management and clinical follow-up are safe anddesirable for the subgroup with mild/moderate pelvic dilatation and preservedrenal function.