RAM2: animal study for safety evaluation of the new artificial urinary sphincter uroactive on a castrated RAM model.

Purpose: Artificial urinary sphincters (AUS) are largely used to treat severe urinary incontinence in men, due to reduced outlet resistance. The aim of this animal study was to assess safety of a new electronic artificial urinary sphincter (UroActive™, UroMems, France) on a castrated ram model.

Methods: RAM study was a non-clinical study, led in a center agreed for animal good laboratory practice studies. In 2019, 20 rams have been implanted with the UroActive device. There were 4 groups of rams, followed respectively 4, 13, 26 and 52 weeks after activation. Similarly to the test animals, 6 rams were operated and left unimplanted (sham group). The animals were implanted, and then let in recovery during 4 weeks before activation. At the activation, a pressure of 120 cmH₂O ± 10 cmH₂O was set. The occlusive cuff was in open position during the day, and in close position during the night, with an opening frequency of 15 min every 1 h and 45 min. At the end of the study, the animals were euthanized and expert pathologists analyzed the urinary system.

Results: Implantation was successfully performed. Two implanted animals presented a infection at control unit site, which one required a premature euthanasia. In all other animals, no signs of discomfort or pain were noted. No urethral erosion or stenosis was observed.

Conclusion: This non-clinical study showed an objective analyze of consequences of an artificial urinary sphincter on local tissues in rams. Under the conditions of this safety study, the UroActive™ device is considered suitable for implantation around urethra.