Particle migration after transurethral injection of carbon coated beads for stress urinary incontinence

Despite 20 years of experience with injectable bulking agents for stress urinary incontinence results are rather disappointing. The satisfying initial results of collagen injection are rapidly decreasing with time, whereas synthetic bulking agents have shown problems with migration and biocompatibility. The ideal bulking agent would be permanent with a good clinical long-term success rate. We report our experience with Durasphere (Carbon Medical Technologies, Inc., St. Paul, Minnesota), a new injectable bulking agent containing carbon coated beads.

Seven men and 13 women with a mean age of 62.5 years underwent transurethral submucosal injection. The 13 female patients had been diagnosed with type III stress urinary incontinence and each had undergone at least 1 unsuccessful previous operation for urinary incontinence. There were iatrogenic and traumatic sphincter lesions in 6 and 1 of the male patients, respectively. Mean volume injected per treatment was 6.0 cc. Mean followup was 10 months.

After 6 months 76.9% of the female patients were improved but after 12 months the success rate decreased to 33%. In the male patients after 6 months the success rate was 66%, which decreased to 33% after 12 months. At the 6-month followup we observed significant migration of the carbon coated beads into the local and distant lymph nodes as well as into the urethral mucosa.

Due to limited success and proved particle migration, carbon coated beads do not show any improvement over existing bulking materials. The clinical effect of bead migration must be determined before extended use of this substance.