The modified sting procedure to correct vesicoureteral reflux: improved results with submucosal implantation within the intramural ureter.

PURPOSE: With the advent of tissue bulking agents, in particular dextranomer/hyaluronic acid copolymer (Dx/HA), for endoscopic implantation for vesicoureteral reflux (VUR), there has been a major shift in the surgical paradigm throughout Europe, and more recently, in the United States. We describe a modification of the technique used for implantation that has significantly improved our results.

MATERIALS AND METHODS: Between October 2001 and October 2003, 285 children 7 months to 15 years old (mean age 4.6 years) underwent endoscopic implantation of Dx/HA for VUR at our institutions. A modified STING (subureteral transurethral injection) procedure (implantation submucosally within the intramural ureter) was introduced during the last year of the study. The average volume of injected material was measured for each ureter. Renal sonography was performed to determine if hydronephrosis was present. At 3 months flouroscopic voiding cystourethrograms were used to evaluate for the presence of VUR. A subset of 122 patients treated with STING (52) were compared to those treated with modified STING (70).

RESULTS: A total of 459 ureters in 231 girls and 54 boys were treated (174 bilateral cases). Mean maximum grade per patient was 2.5/5. Mean injected volume was 0.9 cc ureter. There were 181 patients with at least 3 months of followup. After 1 treatment 76% (137 of 181) of cases were cured (grade 0 reflux), while 54% (24 of 44) of the failures were improved. The overall cure rate was 94% for grade I, 85% for grade II, 78% for grade III and 71% for grade IV reflux. The patients treated with STING had a mean age of 4.8 years, mean maximum reflux grade was 2.5 and success rate was 71% (37 of 52; 86% grade I, 89% grade II, 70% grade III and 63% grade IV reflux). The patients treated with a modified STING had a mean age of 5.5 years, mean maximum grade was 2.8 and a success rate was 89% (62 of 70; 100% grade I, 92% grade II, 91% grade III and 90% grade IV reflux). Ureteral success rates were significantly (p <0.01) greater for the modified STING (92%) vs the standard STING (79%). There were no cases of hydronephrosis at 3 months postoperatively.

CONCLUSIONS: The majority of patients undergoing minimally invasive therapy for VUR with Dx/HA are cured after 1 treatment. The modified STING is our preferred method of implant injection for the correction of VUR and in our hands produces a resolution rate of 89% (92% of ureters). The technique optimizes ureteral coaptation, is easy to perform and is not associated with any significant short-term complications. Persistence of VUR in a minority of patients continues to be the only significant adverse effect of endoscopic implantation.