Background: Experience in using polyalcohol-polyacrylate copolymer (PPC) demonstrates not only its high efficacy but also higher risk of obstructive complications(OC) associated with its use when compared with otherimplants.Identification and furtherstudy ofrisk factorsfor OC may improve safety of PPC use.

Materials and methods: A retrospective analysis of medical data of 774 patients, who underwent treatment using PPC in 5 clinics, was performed. Patients were divided into 2 groups. Group I included 733 children without OC, among them 435 (59,3%) girls and 298 (40,7%) boys. Median age was 41 months [18,0;81,0]. STING technique was used in 668 (91.1%) children, HIT was used in 65(8,9%) patients. Group II included 41(5%) patients with OC, median age was 21,5 months [12,0;43,0]; there were 27 (65.9%) boys, and 14 (34.1%) girls. STING techniquewas used in 18 (41.5%) patients,while HIT technique was used in 23 (58,5%) children. Renal ultrasound was performed 1 day, 1 month, 3, 6 and 12 months after the surgery, and then every 6 months, while voiding cystourethrogram was performed 4-5 months after endoscopic treatment. Patients with OC underwent diuretic renography.

Results: Patients in group II were younger than patients in group I (p=0,002). OC are more common in children with high grade reflux (p<0.001). Incidence of OC is higher in boys than in girls (p=0,003). HIT technique increases the risk of OC (р<0,001). OC were almost 2 times more common after the second injection than after the first endoscopic treatment (р>0.05). OC have developed within time period of 1 to 41 months since the last endoscopic treatment.

Conclusions: Early age, male sex, high grade reflux and HIT technique are the risk factors for OC after endoscopic treatment for reflux with the use of PPC. Patients after endoscopic treatment using PPCshould be monitored for at least 48 months.

Authors declare lack of the possible conflicts of interests