Introduction: The UroMems artificial urinary sphincter (eAUS) is a novel implantable device designed to treat stress urinary incontinence in men and women. It is composed of an occlusive cuff (OC) and a Control Unit (CU) which includes a reservoir, an automatic pump, and electronic components that allow cuff pressure to be set wirelessly. The aim of this study was to evaluate the safety of the eAUS chronic implantation in an animal model (wether).
Methods: After a 2-month follow-up (FU) pilot study with 2 implanted wethers, the study was designed for 3 different FU groups with timepoints at 4, 13 and 26 weeks after device activation. There were 4, 4 and 6 test animals, as well as 1, 1 and 2 control animals in the 4, 13 and 26-week groups respectively.
Test animals were implanted with the OC around the urethra connected to the CU placed submuscularly on the right side of the abdomen. Control animals underwent the same surgery without device implantation and had similar monitoring to the test animals.
After a 5-week healing period, the eAUS was activated with a device pressure of 120 cmH2O. To reduce animal discomfort, the eAUS was programmed to open the cuff during the day and close it at night with opening periods of 15 minutes every 2 hours. Device check-up was performed at the end of the study and at 4 and 13 weeks for groups with longer FU.
At study termination, all animals were euthanized. Macroscopic, microscopic, and blood analyses were performed. CU data was downloaded.
Results: All 14 test animals were implanted without surgical difficulty with 4.0 cm (n=6), 4.5 cm (n=7) or 5.0 cm (n=1) cuff sizes.
There were no premature deaths. Early infection at CU site after implantation with positive bacterial cultures (Pasteurella multocida and fusobacterium necrophorum) was observed in 1 animal in the 4-week FU group.
All devices were functional from activation to explantation.
CU rotation at implantation site was observed in 1 animal at activation and was stable, without clinical or functional consequences.
Blood analyses and histology showed results compatible with chronic implantation, with limited inflammation and fibrous encapsulation compared to control animals.
Conclusions: This study shows that the UroMems eAUS can be successfully implanted and maintained in an animal model. One infection occurred, linked to probable perioperative contamination; no other adverse event was observed. The local and systemic effects of the eAUS were consistent with other foreign device implantations at 1, 3 and 6 months. The devices remained functional throughout the study, providing control of cuff pressure through wireless adjustments.