Artificial Sphincters to Manage Urinary Incontinence: A Review

Abstract

Urinary incontinence affects more than 300 million people worldwide. The implantation of a medical device called an artificial urinary sphincter (AUS) is the gold standard treatment when conservative and minimally invasive therapies fail. In this article, the AUSs (extra-urethral and endo-urethral sphincters) available on the market, both presented at the research level and filed as patents, are reviewed. The ability of the different solutions to effectively replace the natural sphincter are discussed, together with advantages and some possible side effects, such as tissue atrophy, overall invasiveness of the implant, and so forth. Finally, future research priorities are discussed for both endo-urethral and extra-urethral approaches considering key engineering aspects, such as materials, compression and closure mechanisms, and implantation methods, with the long-term aim of developing an effective, reliable, durable, and minimally invasive AUS capable of restoring a normal quality of life for incontinent patients.

Interaction phenomena between a cuff of an artificial urinary sphincter and a urethral phantom

“…Artificial urinary sphincter (AUS) is considered an effective treatment for male stress urinary incontinence (SUI) resulting from various etiologies, including benign prostatic hyperplasia surgery, neurologic disease, radical cystectomy, congenital anomalies, or trauma . Long‐term outcomes of AUS implantation highlighted a satisfactory repair durability and an improvement of the quality of life . Nonetheless, the implantation of AUS has been associated with complications as tissue erosion and atrophy, which can lead to surgical revision or prosthesis explant in 25% of patients …”

“…In general, AUS consists of an inflatable silicone cuff, a pressure‐regulating balloon (PRB) and a deflating pump . The AMS 800 (Boston Scientific, Boston, MA, USA), which is worldwide considered as the gold‐standard AUS, is based on an occlusive cuff that is approximately 2.0 cm wide when deflated and ranges from 3.5 to 11 cm in length . This cuff is provided as an open deflated band, which is placed by the surgeon around bulbar urethra, shaping it according to the anatomical conformation of urethral duct.…”

“…1 Long-term outcomes of AUS implantation highlighted a satisfactory repair durability and an improvement of the quality of life. [2][3][4][5] Nonetheless, the implantation of AUS has been associated with complications as tissue erosion and atrophy, 6 which can lead to surgical revision or prosthesis explant in 25% of patients. 7 In general, AUS consists of an inflatable silicone cuff, a pressure-regulating balloon (PRB) and a deflating pump.…”

“…3,8 The AMS 800 (Boston Scientific, Boston, MA, USA), which is worldwide considered as the gold-standard AUS, is based on an occlusive cuff that is approximately 2.0 cm wide when deflated and ranges from 3.5 to 11 cm in length. 2 This cuff is provided as an open deflated band, which is placed by the surgeon around bulbar urethra, shaping it according to the anatomical conformation of urethral duct. The cuff pressure is set as a constant value at the time of device implant and depends on the PRB chosen by the surgeon.…”

A novel power supply system for puborectalis‐like artificial anal sphincter

“…The idea of AAS is inspired by artificial urethral sphincter (AUS). “An AUS is a prosthesis that fully restores urinary continence by replacing the function of the natural urinary sphincter in patients affected by severe urinary incontinence” . According to Marziale and colleagues review, commercial AUSs have been developed for many years.…”