Predicting resolution of the primary obstructed megaureter
Reviewed by Neil Featherstone

Primary obstructive mega ureter (POM) is the congenital dilatation of the ureter in the absence of other structural urinary tract anomalies and comprises 10–20% of prenatal hydronephrosis cases. It is often detected during workup for prenatal hydronephrosis and confirmed using micturating cystourethrogram (MCUG) and MAG3 imaging. Although some patients with more severe dilatation, recurrent infections or worsening kidney function may warrant surgery, most patients with POM will gradually improve without intervention. Establishing early predictors for spontaneous resolution of POM remains a topic of interest and could prevent unnecessary surgery in this population. This is a large single-centre study comprising 159 patients. Median age at baseline was one month and median follow-up was 13 months. During follow-up 89 (56%) of patients had spontaneous resolution, 57 (36%) progressed to surgery, nine (6%) had stable / worsening hydronephrosis pending further investigations and four (3%) were lost to follow-up within the follow-up period. Of the 57 patients requiring surgery, 40 (70%) were based on diuretic renogram findings (18 had prolonged T1/2 time, 11 had decreased split renal function, 11 had both), seven (12%) were due to urinary tract infection (UTI) and 10 (18%) were due to worsening sonographic findings. Median age at surgery was seven months and ureterovesicostomy was performed in 45 cases (79%). On survival analysis, APD>15mm, high Society for Fetal Urology (SFU) grade of hydronephrosis, ureteral dilatation and ureteral tortuosity were associated with a decreased likelihood of resolution. While smaller studies have previously shown that certain ultrasound parameters can be utilised for predicting resolution, this study confirms these findings in the largest cohort published to date. It may be possible to adopt a more conservative approach in lower risk patients with less frequent imaging, invasive testing and follow-up.

Spontaneous resolution of primary obstructive megaureter: risk stratification and prediction eased on early sonographic factors.
Khondker A, Kim K, Ahmad I, et al.
JOURNAL OF UROLOGY
2025;213:485–93.