Long-Term Preservation of Dextranomer/Hyaluronic Acid Copolymer Implants After Endoscopic Treatment of Vesicoureteral Reflux in Children: A Sonographic Volumetric Analysis

Abstract

PURPOSE: We compared injected volume of dextranomer/hyaluronic acid with sonographic volumes obtained 2 weeks to 36 months postoperatively to evaluate the amount of volume retention with time and to correlate volume retention with voiding cystourethrogram results. MATERIALS AND METHODS: We retrospectively reviewed sonographic volume measurements of dextranomer/hyaluronic acid implants in children at 2 weeks to 36 months postoperatively. Hydronephrosis and percentage of dextranomer/hyaluronic acid retained at each interval were recorded. Average change in volume at each interval was used to compare volume retention with time. The fraction of dextranomer/hyaluronic acid retained was compared to voiding cystourethrogram at 3 months. RESULTS: No patient had new or worsened hydronephrosis. Volumetric data were available for 296, 150, 42, 23 and 20 ureters at 2, 3, 6 and 12 weeks, and 24 to 36 months postoperatively, respectively. Percentage of dextranomer/hyaluronic acid retained was 79% at 2, 74% at 3, 70% at 6 and 78% at 12 weeks, and 65% at 24 to 36 months (p >0.05). While there was no significant difference in mean volume retained between cures (74%) and treatment failures (67%), the 94% cure rate with mega-implants (greater than anticipated volume retention) was higher than that with micro-implants (75%) or nonvisualized implants (70%). CONCLUSIONS: After the initial volume reduction at 2 weeks dextranomer/hyaluronic acid implants remained durable with insignificant volume reduction for up to 36 months postoperatively. Although overall mean volume retention did not correlate with cure, mega-implants were associated with high cure rates and may justify elimination of postoperative voiding cystourethrography.