Background and aims Vesicoureteral reflux (VUR) endoscopic correction becomes a widespread first line procedure for all grade reflux due to its undoubted advantages. To date two tissue-augmenting substances most commonly employed: hyaluronic acid copolymer (Urodex) and polyacrylate/polyalcohol copolymer (Vantris). The goal of this study was to evaluate the success rates of single and double injection techniques for insufflation of these bulking agents.

Materials and methods From 2012 to 2015, 540 children (227 boys and 313 girls) with a mean age of 2.8 years (range 4 months-12 years) were treated endoscopically with single (STING/HIT1) and double injection (HIT2) techniques. Single injection we used in 386 patients (571 renal refluxing units (RRU)) and double injection in 154 patients (236 RRU) with all grades of VUR. We employed both Urodex and Vantris bulking agents. Positive outcome we considered to be a complete elimination of reflux after a single injection. The effectiveness of injection was evaluated with voiding cystouretrography in 6 months.

Results For single injection VUR resolution rate was 73,9% and for double injection VUR resolution rate was 86,4%. Double injection technique was more effective than single injection for both Urodex (Pearson χ-squared 67,6, p=95%) and Vantris (Pearson χ-squared 10,17, p=95%). There was no statistically significant difference in Urodex and Vantris effectiveness with double injection technique (Pearson χ-squared 0,77, p=95%). Vesicoureteral junction obstruction, requiring ureteral reimplantation, developed in 4 ureters, treated with Vantris (0,6%). Six patients (0,95%) developed febrile urinary tract infection.

Conclution Our results confirm that double injection technique is more effective then single injection for endoscopic treatment of VUR. Urodex and Vantris injection effectiveness is the same in double injection technique. There is a necessity for long-term follow-up of patients, treated with Vantris, due to a possible late onset ureteral obstruction.