The early experience and technical aspects of endoscopic subureteral polydimethylsiloxane injection for vesicoureteral reflux

Purpose: We reviewed the operative outcome and the cause of failure for performing subureteral injection of polydimethylsiloxane (PDS, Macroplastique®, Uroplasty Inc. Geleen, The Netherlands), when it is used as a bulking agent for the endoscopic treatment of vesicoureteral reflux (VUR) patients. Materials and methods: A total of 29 patients (a total of 37 ureters), with primary grades I to V VUR were treated with a single subureteral injection from 2001 to 2004; these patients were followed for an average of 21.5 months. Each patient underwent preoperative voiding cystourethrography, renal ultrasound, a dimercapto-succinic acid (DMSA) scan and urine culture. With the patient under general anesthesia, the PDS implant was injected transurethrally at the 6 o'clock position of the ureteral opening in the affected renal unit by a modified subureteral transurethral injection (STING) procedure. Renal ultrasound was done at 1 week and voiding cystourethrography was done at 3 months to rule out obstruction at the injection site and/or persistent reflux, respectively. Cure was defined as an absence of VUR on voiding cystourethrography at 3 months after injection. Statistical analyses were performed using the chi-square test. Results: The grade of reflux was I, II, III, IV and V in 6, 4, 12, 9 and 6 ureteral units respectively. After a single injection, the VUR was cured in 30 ureteral units (81.1%). There were 7 (18.9%) patients who received a second injection after a failed single injection. In these patients, the injected PDS volume was not changed on ultrasound. On the other hand, cystoscopy showed mound displacement in 4 patients, no volcano appearance but rather a broad elevation in 2 patient, and distal ureteral fistula and mound extrusion in 1 patient. Conclusions: These results suggest that endoscopic subureteral polydimethylsiloxane injection is an effective treatment of VUR. The efficacy of subureteral injection can be improved by using the correct injection technique.