Endoscopic Balloon Dilation for Primary Obstructive Megaureter in Children: Early Outcomes and Complications-A Case Series.

Background and Objectives: Congenital urological malformations are among the most frequent causes of pediatric chronic kidney disease. Endoscopic balloon dilation and ureteral stenting can be considered less invasive options compared to conventional surgery for primary obstructive megaureter (POM). Nevertheless, the long-term results and side effects of these methods have not yet been well documented. The purpose of this study is to analyze the effectiveness and safety of the endoscopic treatment of POM in children, with the aim of assisting clinical decision making and improving treatment plans. Materials and Methods: A retrospective longitudinal study was performed at the Pediatric Surgery Department of the "M.S. Curie" Emergency Clinical Hospital for Children in Bucharest between October 2020 and September 2024. Eleven endoscopic interventions were performed in five pediatric patients (four boys and one girl) who had six affected ureters, with a median age of 22 months. The inclusion criteria were retrovesical ureter dilation > 7 mm and no prior surgeries of the ureterovesical junction. Cases with secondary megaureters were excluded from the study. The procedures comprised HPEBD and temporary double-J (DJ) stent placement, with systematic postoperative monitoring. Success was defined as improvements in symptoms, a decrease in hydronephrosis, and the preservation of renal function. Results: A final success rate of 83.3% was achieved with endoscopic treatment. Complications were noted in 73% of cases: Clavien-Dindo Grade I (30%); Clavien-Dindo Grade II (20%); Clavien-Dindo Grade IIIb (50%). The documented complications consisted of balloon rupture, stent migration, restenosis, and febrile urinary tract infections (UTIs). Nonetheless, no major complications were observed. The postoperative monitoring showed that renal function was stable and that hydronephrosis had improved gradually. Conclusions: Endoscopic procedures offer a promising, minimally invasive treatment for POM in children with a good success rate. However, the high complication risk necessitates careful patient selection, post-surgery monitoring, and clear guidelines.