The development and evolution of artificial urethral sphincters

Area of Science:

• Urology
• Biomedical Engineering
• Medical Device Design

Background:

• Urinary incontinence affects millions globally, necessitating effective management devices.
• The development of mechanical devices has aimed to restore urinary continence through various mechanisms.
• Previous designs faced challenges with urethral integrity and efficacy.

Purpose of the Study:

• To review the history and evolution of mechanical devices for urinary continence.
• To analyze the design principles and clinical implications of different continence devices.
• To compare the efficacy and safety of 'volume set' versus 'pressure set' hydraulic sphincters.

Main Methods:

• Comprehensive review of historical and contemporary mechanical continence devices.
• Analysis of device designs, including Foley clamp, various sphincters (Kaufman, Giori, Summers and Rosen, Gruneberger, Cleveland Clinic magnetic, Craggs, AMS family).
• Detailed examination of active hydraulic device designs, focusing on pressure application and foreign material interaction.

Main Results:

• Identified a range of mechanical devices developed for urinary continence over time.
• Highlighted design challenges related to urethral pressure application and foreign body response.
• Demonstrated that 'pressure set' hydraulic sphincters (e.g., AMS 800) are superior to 'volume set' devices for urethral integrity and efficacy.

Conclusions:

• The evolution of mechanical continence devices shows a trend towards more sophisticated hydraulic systems.
• 'Pressure set' hydraulic designs represent a significant advancement over 'volume set' devices.
• Future artificial implant designs should prioritize optimal pressure distribution and biocompatibility to ensure urethral health and device function.