Lack of distant migration after injection of a (125)iodine labeled dextranomer based implant into the rabbit bladder

Purpose: In recent years endoscopic treatment of stress incontinence and vesicoureteral reflux has been Introduced. Reports of possible particle migration of the injected material to distant organs in humans and experimental animals have led to a search for biological nonmigration products. An implant found to have a good clinical effect in these conditions is dextranomer in hyaluronan. We performed this study in rabbits to investigate the possible migration of dextranomer particles. Materials and Methods: (125)Iodine labeled dextranomer particles were injected into the submucosal space of rabbit bladders, and samples of blood and various tissues were examined for radioactivity at scheduled intervals during a 28-day period. Furthermore, whole body autoradiography was performed 1 day, and 1 and 4 weeks after injection. Results: Radioactivity was found in blood samples and in all tissues but it remained at the background activity level except in the thyroid, where uptake representing free (125)iodine was detected. In the bladder 41 and 45% of the injected dose remained within the bladder wall 1 day and 4 weeks, respectively, after injection. The remainder of the dose probably disappeared from the bladder wall by leakage into the urine shortly after deposition, as indicated by the finding of 10-fold higher urine radioactivity levels at day 1 than at day 28 after injection. Conclusions: No distant migration of dextranomer particles occurs after submucosal injection of such an implant in the rabbit bladder wall.