An overview on artificial urinary sphincters

This study reviewed artificial urinary sphincters for treating urinary incontinence. The authors concluded that artificial urinary sphincters can be used as an effective first-line procedure for managing incontinence after prostate surgery.

Urinary incontinence is common among men undergoing prostate surgery. Prostate surgery often damages the urethral sphincter, the muscles which control the exit of urine. Damage to the sphincter, called urethral sphincter dysfunction, often causes urinary incontinence after surgery.

Artificial urinary sphincters can help restore urinary continence among those with urethral sphincter dysfunction. The artificial sphincter is implanted during a surgical procedure. The artificial sphincter includes an inflatable cuff that fits around the bladder base, close to the upper part of the urethra (the urine tract). Inflation of the cuff prevents involuntary urine leakage, and deflation allows the passing of urine when desired. Cuff inflation (and therefore urination) is typically controlled by squeezing and releasing a pump located in the scrotum. The aim of this study was to provide an overview of artificial urinary sphincters and their surgical outcomes. 

Before treatment with an artificial urinary sphincter, patients are thoroughly screened for symptom severity and other medical conditions. A wait of 12 months after diagnosis is usually recommended in order to effectively monitor symptoms before surgery. The device can usually be activated within 6 weeks of surgery.

The AMS 800 was the most commonly used artificial sphincter device in this review, with many studies reporting high satisfaction rates. Overall, in various studies, between 61 to 100% of men were noted to achieve continence after AMS 800 placement. In one large study, 59% of men reported a marked improvement in symptoms (using 1 or no incontinence pads per day after surgery), and 94% of men would recommend the procedure to family or friends. Other studies noted significant symptom improvements in up to 89% of men treated. However, high-quality evidence examining long-term effectiveness is still lacking.

More recently developed artificial urinary sphincter devices include the Flow Secure, the Zephyr ZSI375, the Periurethral Constricture, and the Tape Mechanical Occlusive Device. Early studies examining these new devices have demonstrated promising results. The Zephyr ZSI375 and the Tape Mechanical Occlusive Device in particular were associated with good effectivity. These minimally invasive procedures may significantly reduce operative and rehabilitation times, as well as surgical complications, compared to older devices requiring open surgery. However, larger studies are needed to confirm the preliminary results investigating these new devices.

Overall, artificial urinary sphincter devices are considered safe. Advances in the materials used in artificial sphincters have reduced the likelihood of skin irritation or infection after surgery. Infection rates are generally low (ranging from 1 to 8%). Device erosion rates reportedly range from 5 to 10%, and typically occur at 19 months after surgery. Erosion rates were noted to be higher among men with prior radiation therapy or those with urethral stents. Artificial sphincter devices were noted to remain functional in 74% of men 5 years after implantation, in 57% at 10 years after surgery, and in 41% at 15 years after surgery. However, tissue surrounding the implanted sphincter can get damaged over time. Damaged tissue is the most common reason requiring additional surgical intervention (noted in 8 to 14% of men one year after surgery).

This review concluded that artificial urinary sphincters are an effective treatment option for urinary incontinence following prostate surgery.