Late-onset Uretero-vesical Junction Obstruction Following Endoscopic Injection of Bulking Material for the Treatment of Vesico-ureteral Reflux.

Objective: To characterize patients who develop late obstruction after subureteral injection of bulking agent for the treatment of pediatric vesicoureteral reflux (VUR).

Methods: We retrospectively evaluated the medical records of all patients who underwent endoscopic injection for the correction of VUR during 2008-2015 in 2 centers in Israel: Bnai-Zion Medical Center, Haifa, and Schneider Children's Medical Center, Petah Tikva. Nine patients who developed late-onset obstruction were included in the study, and their data were reviewed and analyzed.

Results: Three boys and 6 girls with mean age of 3 years were included in the study. All patients had moderate-to-high grade VUR. Following injection, all children had a radiographic evidence showing resolution of the reflux. During follow-up, patients were diagnosed with late obstruction in a mean time of 13.4 months. All patients underwent open re-implantation.

Conclusion: Late-onset obstruction may develop in patients treated with subureteral injection for VUR. Patients with high grade reflux and dilated ureters are at risk of late obstruction. Long-term follow-up with ultrasound is mandatory following endoscopic treatment of VUR.