Endoscopic balloon dilatation of primary obstructive megaureter: method standardization and predictive prognostic factors.

The management of congenital primary obstructive megaureter (POM) is usually conservative, especially during the first year of life. Endoscopic high-pressure balloon dilatation (EHPBD) is indicated when symptoms, increasing dilatation and progressive renal damage are recorded, particularly in children younger than one year of age. We identified and described endoscopic prognostic factors predicting the success or failure of endoscopic dilatation. Thirty-eight patients (33 M;5 F) with POM from 2005-2018 were included. Diagnosis was based on US distal ureter dilatation (>7 mm), obstructive MAG-3 diuretic renogram and absence of vesicoureteral reflux (cystography). 24 patients were under 1 year of age. All patients underwent cystoscopy and high-pressure balloon dilatation with 3,5 Fr dilating balloon, after ascending pyelography. Median follow-up was of 6.5 years. We identified characteristics with poor prognosis: stenotic punctiform ureteral ostium and/or ostium located in a bladder diverticulum (9 pts) and stenotic tract longer than 1 cm (5 pts). The patients with a stenotic tract shorter than 1 cm (18 pts) were divided into two groups: <5 mm (5 pts) and between 5 and 10 mm (13 pts) showed a good response to dilatation. Endoscopic evaluation of ureteral ostium with pneumatic dilatation when possible is a useful diagnostic and therapeutic solution for POM treatment, especially under one year of age. EHPBD is effective in short stenotic tracts (<5 mm). It may also be repeated with good results in intermediate stenotic sections (5 mm-1 cm). According to our preliminary results, the procedure is more effective if performed earlier (3-7 months of life). Greater cohort and longer follow-up are needed to verify the stability of these results.