Histology Proved Malpositioning of Dextranomer/Hyaluronic Acid in Submucosal Ureter in Patients After Failed Endoscopic Treatment of Vesicoureteral Reflux

PurposeWe histologically investigated the cause of failed endoscopic treatment of vesicoureteral reflux with dextranomer/hyaluronic acid injections in children.Materials and MethodsA total of 192 children underwent dextranomer/hyaluronic acid injection at our institution between January 2008 and September 2010. The study population consisted of 13 children (22 ureters) with vesicoureteral reflux who underwent ureteroneocystostomy following failed endoscopic injections (1 to 2) of dextranomer/hyaluronic acid. In all cases the dextranomer/hyaluronic acid was implanted in the mucosa of the mid to distal ureteral tunnel following hydrodistention of the ureter. The medical records were reviewed, and specimens of the archived distal ureters removed during surgery were examined histologically.ResultsMean patient age was 4.1 years. Mean dose of dextranomer/hyaluronic acid was 0.9 ml (both treatments) and mean lag between treatments was 13.4 months. Indications for open surgery were recurrent urinary tract infections and/or residual or aggravated reflux grade IV or higher. Histological study revealed that the dextranomer/hyaluronic acid was malpositioned in 21 of 22 ureters, residing in the muscle fibers in 2, adventitia in 14 and periureteral space in 5.ConclusionsThis is the first known study to provide a histologically proved cause of failure of endoscopic treatment of vesicoureteral reflux with dextranomer/hyaluronic acid injections in children. Malpositioning of the material outside the submucosal ureter was identified in a high percentage of cases. Larger studies are needed to corroborate these findings.