Efficacy of the modified STING procedure for the treatment of high grade vesicoureteral reflux

Purpose: The modified subureteral transurethral injection (STING) has been reported to increase the success of endoscopic treatment of high grade vesicoureteral reflux (VUR). This study was performed to assess the efficacy of the modified STING procedure compared to conventional STING in the setting of high grade VUR. Materials and Methods: We retrospectively reviewed the medical records of 40 consecutive children (46 ureters) with a median age of 5.32 years (range 1 to 10 years) who underwent endoscopic treatment of grade IV to grade V VUR between February 2004 and December 2006. The modified STING was performed by applying a direct pressure stream of irrigation fluid into the ureter in order to define the injection site within the ureteral submucosa. The needle was then placed in the ureteral tunnel, and a dextranomer/hyaluronic acid copolymer (Dx/HA) was injected into the submucosal intraureteral space, tracking along the entire length of the detrusor tunnel. Modified STING was performed in 27 ureters (grade IV: 13, grade V: 14), and conventional STING was performed in 19 ureters (grade IV: 12, grade V: 7). Follow-up voiding cystourethrography (VCUG) was performed 3 months later. Results: Complete resolution occurred in 82% (22/27 ureters) of the patients undergoing modified STING, including 92% (12/13) of grade IV patients and 71% (10/14) of grade V patients. Three ureters required a second injection to correct VUR. Conventional STING had a success rate of 63% (12/19), [75% (9/12) in grade IV and 43% (3/7) in grade V]. The mean injected volume for the modified STING was 1.23±0.3ml, while that for the conventional STING was 0.95±0.2ml (p=0.03). Conclusions: The modified STING was markedly more successful in the treatment of high grade VUR and carried no significant adverse effects.