Thematic Area: 

Primary Obstructive Megaureter

The following guidance document has been adopted based on standardized reviews and is followed in all ERKNet centers: 


British Association of Paediatric Urologists Consensus Statement on the Management of the Primary Obstructive Megaureter.  

J Pediatr Urol 2014; 10:26-33


Core Recommendations:
  1. Megaureter definition: Retrovesical ureteric diameter >7 mm from 30 weeks’ gestation onwards   
  2. Neonates with prenatally diagnosed hydroureteronephrosis should receive antibiotic prophylaxis; in conservatively managed cases, prophylaxis is recommended for the first 6-12 months of life 
  3. All babies with prenatal ureteric dilatation should have a postnatal ultrasound scan.
    Babies with bilateral ureteric dilatation and boys with unilateral hydroureteronephrosis should have an early MCUG to exclude bladder outlet obstruction (BOO). An MCUG is indicated in all patients to exclude the presence of VUR. Once BOO and VUR are excluded, a MAG-3 isotope scan is indicated in babies with hydroureteronephrosis or isolated ureteric dilatation >10 mm to look for obstruction at the VUJ  
  4. Diagnosis of obstruction: In the asymptomatic patient, the presence of an initial differential renal function (DRF) below 40%, or a drop in DRF of 5% on serial scans, and/or increasing dilatation on serial ultrasound scans, are suggestive of obstruction.
    Delayed transit on MAG-3 in the presence of stable or improving dilatation, and a DRF >40%, in an asymptomatic patient, are not considered strong indicators of obstruction. 
  5. Primary obstructive megaureters should primarily be managed conservatively.
    Indications for surgical intervention:
    - Initial DRF <40% (especially when associated with massive hydroureteronephrosis)
    - Failure of conservative management (breakthrough febrile UTIs, pain, worsening dilatation or deteriorating DRF on serial scans)
  6. In children over 1 year of age, ureteric reimplantation with or without ureteral tapering is intervention of choice.
    In infants <1 year, temporary endoscopic stenting is the preferred option, followed by refluxive reimplantation if endoscopic insertion failed.
Comments by evaluators:
  • The condition is defined, but the population is not further defined (e.g. no further information on age range or comorbidities.
  • This is a consensus statement rather than a guideline. The degree of consent in the voting group is not given in detail. Moreover, the voting group was restricted to pediatric urologists.