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

Objectives: The purpose of the study was to evaluate the outcome of prenatally detected ureteropelvic junction obstruction (UPJO) managed with a more conservative protocol.

Methods: The records and imaging studies of 77 consecutive neonates with UPJO identified by fetal hydronephrosis were reviewed. A nonoperative approach was attempted in patients with mild/moderate pelvic dilatation, renal units with good function as ascertained by DMSA scan and a non-obstructed pattern on DTPA. Otherwise, the patients were managed surgically by pyeloplasty. Both groups were prospectively followed and the imaging studies were performed before and after the initial approach and at one-year intervals thereafter.

Results: Of the 77 infants (85 units), 39 were submitted to surgery (33 pyeloplasty and 7 nephrectomy) and 38 were conservatively managed. During follow-up, 9 (24%) of 38 patients in the non-operative group presented renal function deterioration and 3 presented with urinary infections and were submitted to pyeloplasty. Of the 39 patients surgically managed, 76% presented improvement of hydronephrosis and 90% showed a non-obstructed pattern on diuretic renography. The differential renal uptake, as measured by DMSA scan, remained stable in the three groups analyzed (conservative, initial pyeloplasty, and delayed pyeloplasty). There was a minimal improvement in those units submitted to pyeloplasty with impaired renal function at baseline (< 40%). Mean renal uptake was 28.6% at admission and 33.9% at the end of follow-up.

Conclusion: There was a wide spectrum of ureteropelvic junction stenosis. Surgical intervention in a subgroup of patients with severe hydronephrosis and impaired function may possibly improve or preserve renal parenchyma. Conversely, conservative management and clinical follow-up are safe and desirable for the subgroup with mild/moderate pelvic dilatation and preserved renal function.