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

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.

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.

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.

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.