Novel Artificial Urinary Sphincter in the Canine Model: The Tape Mechanical Occlusive Device

Objectives

To assess the functionality, occlusive efficiency, and biocompatibility of a novel artificial urinary sphincter, the tape mechanical occlusive device (TMOD), after implantation in a live canine model, as well as its occlusive efficiency and sizing parameters in human cadavers.

Methods

Three female canines underwent implantation of the TMOD at the level of the bladder neck. Functionality was assessed starting at 2 weeks after implantation and continued for ≤9 weeks. The TMODs were activated at 2 weeks and then deactivated for 3, 30-minute sessions daily to permit voiding. The urethral occlusion pressures and biocompatibility for systemic toxicity and the local tissue response were examined. Additionally, the TMOD was inserted in 3 male cadavers to determine the sizing parameters and to assess the urethral occlusion pressures using pressure profilometry.

Results

In the canine model, the urethral occlusion pressures increased from a range of 9-42 cm H₂O with the TMOD deactivated to a range of 57-82 cm H₂O with the TMOD activated. Pathologic examination revealed unremarkable pseudocapsular tissues surrounding the device. No histologic or structural evidence of systemic toxicity was observed. Sizing parameters similar to those of other urologic implants were confirmed in the male cadavers, and the urethral occlusion pressures increased from 24 to 30 cm H₂O with the device deactivated to 61-105 cm H₂O with the device activated.

Conclusions

The TMOD meets the current standards for an artificial urinary sphincter in terms of functionality, biocompatibility, and achieving desired occlusion pressures following chronic implantation. Additional testing in male canines followed by early human clinical trials is being contemplated.