Artificial urinary sphincter offers versatile option

May 15, 2006

Brisbane, Australia-The artificial urinary sphincter provides"predictable success" in men who suffer from urinary incontinenceafter radical prostatectomy, according to George Webster, MD,professor of urology and head of the section of reconstructiveurology, female urology, and urodynamics at Duke University MedicalCenter, Durham, NC. Functional problems requiring a secondprocedure are not an uncommon problem with the device, he toldattendees at the Urological Society of Australasia annual meetinghere.

Estimates of the incidence of significant stress incontinence in men who have undergone radical prostatectomy range from 5% to 20%, and up to 40% of men experience significant bladder overactivity, which contributes to the problem, Dr. Webster said.

"We can definitely improve the quality of life of those men with stress incontinence with the artificial urinary sphincter," he said of the device, commercially known as the AMS 800 Urinary Control System (American Medical Systems, Minnetonka, MN). "At what point will no further improvement [in post-prostatectomy incontinence] take place? Certainly in patients with mild incontinence, there can be progressive improvement up to a year, perhaps even longer."

Men with mild incontinence can be treated with medication and behavioral techniques, and low-volume patients may benefit from periurethral bulking agents, Dr. Webster said.

"The male sling is hotly debated right now. There are reports of excellent outcomes and other reports of rather poor outcomes, and I think the problem is that we don't know how to select appropriate patients for it. There is a lot of enthusiasm for artificial sphincters in the U.S. because it does cover the whole spectrum of severities with predictable success," he said.

Perineal approach preferred

Dr. Webster described his surgical technique, in which the cuff is implanted in the bulbar urethra, just behind the bifurcation of the corporal bodies. He advocates using the smallest possible cuff size, usually 4.0 to 4.5 cm. He also fills the device with contrast material.

Although there has been recent interest in performing artificial sphincter surgery using an anterior scrotal approach, Dr. Webster prefers a perineal method.

"The problem with the anterior scrotal approach is that it makes it very difficult to implant the cuff at the optimal site, which is behind the crus where the urethra is at its broadest, leading to frequent cuff implantation at too-distal a site where the urethra is more prone to erosion and where cuff fit is less snug," he said.

A less snug cuff fit leads to less efficient compression and poorer continence. Additionally, placement of the cuff more distally may lead to its inadvertent compression against the pubic bone on rising from a chair, activating the device and causing leakage.

"The cuff fit is the feature that most enhances a successful outcome," he said.

Urethral atrophy beneath the cuff was the most common reason for surgical revision among men in Dr. Webster's practice. This event means that a previously snug cuff fit becomes loose, reducing the efficiency of compression.

The review of 591 men who underwent implantation of the AMS 800 artificial urinary sphincter during a 10-year period found that 90% used no pads or one pad per day. Five-year durability outcomes were 80% for primary implantation and 88% for secondary implantation (J Urol 2005; 173:1242-5).

Functional problems with the device that require revision procedures are not uncommon. Of 554 patients in his practice, 159 (29%) needed a further operation. The most common reason was urethral atrophy.

"An initially implanted cuff that seems to be a good size ultimately ends up being too loose," he explained.