Failure of subureteral bovine collagen injection for the endoscopic treatment of primary vesicoureteral reflux in long-term follow-up

Abstract Objectives. To evaluate the long-term efficacy of subureteral glutaraldehyde cross-linked collagen injection (GAX 35) for endoscopic treatment of primary vesicoureteral reflux (VUR). Methods. We prospectively studied 36 patients (58 ureteral renal units), 30 girls and 6 boys with a median age of 6 years (range 2 months to 18 years). All patients had primary VUR and were treated with a single subureteral collagen injection (GAX 35). The patients were followed up by voiding cystography. Results. According to the International Reflux Study Classification, we found the following reflux grades preoperatively: grade I, 2 ureteral units; grade II, 21 units; grade III, 28 units; grade IV, 4 units, and grade V, 3 units. All patients were treated with subureteral bovine collagen injection (GAX 35, mean volume 1.7 mL, range 0.7 to 3.5). All but 3 cases of reflux resolved initially. The mean follow-up was 13 months (range 1 to 108). After 37 months of follow-up, only 5 (9%) of 57 treated units remained reflux free. One unit was followed up for 17 months and also remained reflux free. Conclusions. These data suggest that a single endoscopic subureteral collagen injection is not effective in the long-term follow-up of patients with primary VUR. In the future, it will be important to determine whether the new, currently used, and soon be approved bulking agents show better long-term clinical results to prevent VUR recurrence than bovine collagen does.