Factors associated with spontaneous resolution and surgery in non-obstructive non-refluxing megaureters

Clinical and radiological criteria for predicting surgical approach or spontaneous resolution have been evaluated mainly in primary non-refluxing megaureters detected prenatally. We aimed to analyze these criteria in a retrospectively collected cohort of children with either prenatal or postnatal diagnosis of non-obstructive non-refluxing (NONR) megaureter.

Hospital files of the children with NONR megaureter were evaluated retrospectively for age at diagnosis, presenting complaint, follow-up period, accompanying urologic abnormalities, complications (renal scar and urinary tract infection), and final status.

There were 27 NONR megaureters in 25 patients (male/female: 19/6; prenatal/postnatal: 18/7). Two prenatal cases had bilateral involvement. Spontaneous resolution rate in renal units was lower in postnatal cases than in prenatal cases (2 out of 7 vs. 15 out of 20, OR 7.5). Spontaneous resolution rate was also higher when ureteral diameter was <11 versus ≥11 mm (OR 10.9) and renal pelvis anteroposterior diameter ≤10 mm versus >10 mm (OR 19.2). Surgical intervention rate was higher in the presence of ureteral diameter ≥14 versus <14 mm (OR 22.0). Renal units that underwent surgical treatment showed higher rates of febrile urinary tract infections, renal scarring, and reduced renal function on ^99mTc-MAG3 scintigraphy compared to those without surgical intervention.

Initial management of asymptomatic non-refluxing megaureters should be observational monitoring. Majority of them resolve spontaneously if ureteral diameter is <11 mm with renal pelvis anteroposterior diameter ≤10 mm. However, children with ureteral diameter ≥14 mm are prone to develop febrile urinary tract infection, renal scar, and decreased renal function requiring surgical intervention.