Primary, Non-Refluxive Megaureters: Ureteral Peristalsis Detected on Initial Ultrasound Is Not a Valid Predictor for...

Background/Objectives: Primary non-refluxing megaureters (PM) are common congenital anomalies of the urinary tract. While spontaneous resolution is frequent, reliable non-invasive predictors of outcome are scarce. Ureteral peristalsis is frequently regarded as a sign of functional maturation and favorable prognosis, although supporting clinical evidence is limited. This study aimed to evaluate whether sonographically visible ureteral peristalsis at initial diagnosis predicts spontaneous resolution, pyelonephritis, or the need for surgery in infants with PM. Methods: In this retrospective single-center study, infants diagnosed with primary non-refluxing megaureters before one year of age between 2012 and 2018 were analyzed. Patients with refluxing, secondary, syndromic, or ectopic megaureters were excluded. Sonographic detection of distal ureteral peristalsis at initial examination was recorded. Clinical outcomes included spontaneous resolution, episodes of pyelonephritis (including breakthrough infections under antibiotic prophylaxis), and surgical intervention. Univariate and multivariate logistic regression analyses were performed. Results: Sixty-three infants were included, with a median follow-up of 34 months. Peristalsis was detected in 52.3% at initial ultrasound. Complete spontaneous resolution occurred in 66% of patients, while 20.9% required surgical reimplantation. The presence of peristalsis at diagnosis was not associated with spontaneous resolution, time to resolution, occurrence of pyelonephritis, breakthrough infections, or surgical intervention. Multivariate analysis confirmed that initial peristalsis was not an independent predictor of outcome. Conclusions: Sonographically visible ureteral peristalsis is a transient and inconsistent finding in infants with primary non-refluxing megaureters and does not predict clinical outcome. Peristalsis observed on initial ultrasound should not be used as a decision-making parameter in the management of PM during the first year of life.