Artificial Urinary Sphincter Placement 

Updated: May 16, 2016
Author: Kamran P Sajadi, MD; Chief Editor: Edward David Kim, MD, FACS 

Overview

Background

A biological urinary sphincter prevents urinary flow via mucosal coaptation, compression, and pressure transmission. An artificial urinary sphincter (AUS) mimics the biological urinary sphincter by providing a competent bladder outlet during urinary storage and an open unobstructed outlet to permit voluntary voiding.

An artificial urinary sphincter is the only device that closely simulates the function of a biological urinary sphincter. Decades of advances in mechanical design, applications of new technology, and lessons learned from clinical experience have inspired notable improvements.

Novel and ingenious in technical design, the AMS 800 (American Medical Systems, Minnetonka, Minn) device has restored the quality of life to thousands of patients plagued by severe stress urinary incontinence. The AMS 800 prosthesis is the most effective, reliable, and durable surgical treatment for men with postprostatectomy urinary incontinence, achieving social continence rates of 75-95%.

For additional information, see the Medscape article Urinary Incontinence Relevant Anatomy. For supplementary information on urinary incontinence in general, see Medscape’s Urinary Incontinence and OAB Resource Center.

History of the Procedure

Artificial devices to control incontinence are not new. Foley described an artificial sphincter in 1947 that was an externally worn urethral cuff attached to a pump kept in the patient's pocket. The first artificial urinary sphincter to resemble the current model was developed by Dr. Brantley Scott in 1972. Called the AS 721, it consisted of a fluid reservoir, an inflation pump, a deflation pump, and an inflatable cuff with 4 unidirectional valves. The fluid within the sphincter components conveyed the hydraulic pressure to the cuff. Unfortunately, it was mechanically unreliable and carried high urethral erosion rates.

In 1974, a newer model (AS 761) emerged. This model offered a pressure-regulating balloon that allowed automatic cuff closure. This pressure-regulating balloon provided constant predetermined pressure within the hydraulic system, so that the pressure-volume relationship became very predictable.

The AS 761 device was quickly modified into the AS 742 model. This newer sphincter eliminated the need for an inflation pump. The pressure-regulating balloon functioned as a reservoir for cuff fluid. A delay-fill resistor allowed enough time for the patient to void to completion before the urethral cuff closed. However, this prosthesis still was not ideal for patient use.

Introduced in 1979, the AS 791/792 device featured a control assembly that merged the valves and the resistor into a single unit. Surgical implantation was easier, with fewer components and fewer connections. However, the control pump did not have on-off capability. The risk of urethral atrophy and cuff erosion remained high. A second operation was required for activation of this device.

Through continued evolution and improvement, the AMS 800 device was introduced in 1983. During the modification process, the control assembly (valves and resistor) was moved into the pump chamber. This model featured a new locking mechanism that allowed the cuff to remain in either the open or the closed position; thus, the cuff could be left in a deflated (open) state after implantation and could be activated 6-8 weeks later without the need for a second operation.

In 1987, AMS introduced a narrow-backed cuff. This modification improved transmission of pressure to the underlying urethra or bladder neck, which has been proven to decrease the risk of erosion and tissue atrophy. In 1988, the kink-resistant and color-coded tubing was introduced.

The AMS 800 is the most widely used and successful artificial urinary sphincter available. To date, over 94,000 men worldwide have been treated with an AMS 800.

Problem

An artificial urinary sphincter is reserved for treatment of complex or severe stress urinary incontinence. Type III stress urinary incontinence, or intrinsic sphincteric dysfunction, is the inability of the urethra to maintain effective resting urethral closure pressure sufficient to keep the patient clinically dry at rest and during periods of reasonable physical activity.

Etiology

Patients with intrinsic sphincteric dysfunction include men who have undergone radical retropubic prostatectomy (including laparoscopic or robotic-assisted radical prostatectomy), radical perineal prostatectomy, or transurethral resection of the prostate (TURP); patients with previous pelvic trauma or a history of pelvic radiation; and women in whom anti-incontinence procedures have failed. Patients with spinal cord injuries, myelomeningoceles, or other causes of neurogenic bladder may also have intrinsic sphincter dysfunction.

Pathophysiology

The normal voiding cycle requires that the urinary bladder and the sphincter work as a coordinated unit. The urinary bladder has two functions: it relaxes to store urine (storage or filling phase), and it contracts to eliminate urine (voiding phase). During urinary storage, the bladder is placid and acts as a low-pressure reservoir. During voiding, the bladder actively contracts to act as a pump. The urinary sphincter has two functions: it contracts to store urine and it relaxes to eliminate urine. During urinary storage, the urinary sphincter remains closed to prevent urine loss. At the beginning of the voiding phase, the urinary sphincter opens to allow unobstructed urination.

Urinary incontinence results from dysfunction of the bladder, the sphincter, or a combination of both. Bladder overactivity causes urinary frequency, urgency, and urgency incontinence. Bladder underactivity causes urinary retention. Sphincteric overactivity causes urinary retention. An inadequate or hypoactive sphincter results in stress incontinence. A combination of bladder overactivity and sphincteric underactivity results in mixed urinary incontinence—stress and urge.

Intrinsic sphincteric dysfunction is a complex form of stress incontinence whereby the urethra always remains open. Risk factors for intrinsic sphincteric dysfunction in men include radical prostatectomy, TURP, previous bladder neck surgeries, pelvic radiation, pelvic trauma, and neurologic disorders.

A common denominator of intrinsic sphincteric dysfunction is low urethral resistance at rest and during periods of physical activity. Whenever the intravesical pressure becomes greater than the urethral resistance, stress incontinence ensues. A reliable method of restoring continence is by artificially increasing the urethral resistance. Many approaches to this problem have been devised over the years. The main criterion for implanting an artificial urinary sphincter is a relatively normal detrusor in a setting of intrinsic sphincteric dysfunction.

Presentation

Patients with intrinsic sphincteric dysfunction present with the classic history of stress urinary incontinence. They experience predictable loss of urine whenever the intravesical pressure exceeds that of the urethral pressure (eg, when coughing, laughing, sneezing, sitting down, or performing the Valsalva maneuver).

Often, patients with intrinsic sphincteric dysfunction complain of involuntary urine loss when changing their body position (eg, when rising from a sitting position). Women with intrinsic sphincteric dysfunction experience more urine loss and require thicker pads than women with incontinence due to urethral hypermobility.

Intrinsic sphincteric dysfunction can often be distinguished from other causes of incontinence by patient history and physical examination. In patients with pure intrinsic sphincteric dysfunction, symptoms of urinary frequency, urgency, and nocturia are typically absent. However, when such storage symptoms are present, coexisting overactive bladder should be suspected. As such, patients should undergo preoperative endoscopic and urodynamic evaluations (see Workup).

Indications

Candidates for artificial urinary sphincter include patients with bothersome stress urinary incontinence due to ISD. Indications in men and women of all ages include the following:

  • Postprostatectomy incontinence, which is the most common indication for placement of an artificial urinary sphincter. Placement of the artificial urinary sphincter should be deferred for at least 6 months after prostatectomy; many physicians defer placement for up to 1 year because patients often regain some or all continence during this time.

  • Intrinsic sphincteric dysfunction following pelvic fracture, spinal cord injury, urethral reconstruction, or multiple previous failed anti-incontinence procedures.

  • Neurogenic bladder with associated sphincter or bladder neck incompetence.

  • Although not commonly done in the United States, in Europe the artificial urinary sphincter has been used in women with stress incontinence due to intrinsic sphincter deficiency. This is done through an abdominal, not perineal or vaginal, approach. Long-term data now support this indication, with low rates of mechanical problems and high success rate.

Careful patient selection is arguably the most important factor in predicting success of the artificial urinary sphincter, and the following should be considered:

  • Female patients and children require bladder neck placement of the sphincter and must be motivated to perform and capable of performing clean intermittent catheterization, as this may be required because of postoperative urinary retention.

  • All patients must have sufficient sophistication and hand functionality, as well as manipulative strength, to operate the pump and its associated lock-out mechanism.

  • All patients must understand the potential complications of the operation and the possibility of future surgical interventions for tissue atrophy, cuff erosion, cuff migration, mechanical failure, and device infection. The long-term reoperation rate is about 20%.

Essential characteristics of an ideal patient include highly motivated personality, good manual dexterity, relatively normal detrusor, absence of urinary tract infection (UTI), failure of alternative means of incontinence control, and realistic expectations. Although some patients may expect to remain completely dry, a realistic and satisfactory goal is achieving "social continence", which is generally defined as requiring no more than one incontinence pad a day. Careful patient selection can greatly reduce the likelihood of a disappointed patient and surgeon.

A study by Ziegelmann et al evaluated the impact of patient age on device outcomes among patients undergoing primary artificial urinary sphincter. The study found that although overall artificial urinary sphincter device survival is similar, patients aged >80 years are more likely to experience erosion or infection compared with younger patients. The authors added that despite this, the overall device failure rate is low, and artificial urinary sphincter might be considered for appropriately selected and counseled octogenarians.[1]

Relevant Anatomy

The urethra is composed of an inner epithelial lining, a spongy submucosa with rich vascular plexus, a middle smooth muscle layer, and an outer layer of fibroelastic connective tissue. The spongy submucosa is responsible for providing urethral occlusive pressure. The ability of the urethral mucosa to coapt to generate an adequate urethral closing pressure is an important continence mechanism. Urethral smooth muscle and fibroelastic connective tissues serve to circumferentially augment the occlusive pressure generated by the submucosa.

The urinary sphincter is composed of an internal sphincter and an external sphincter. In females, the internal sphincter is composed of the bladder neck and proximal urethra. In males, the internal sphincter is composed of the bladder neck and prostate. Both males and females possess an external sphincter known as the rhabdosphincter. The rhabdosphincter is omega-shaped and is composed of 2 types of striated muscle fibers—fast twitch and slow twitch. Contraction of fast twitch fibers causes sudden stopping of the urinary stream. This is known as the voluntary guarding reflex. These fibers are responsible for allowing Kegel exercises. Slow twitch fibers maintain the constant tonus of the external sphincter, which is important in daily physical activities. This is known as the involuntary guarding reflex.

For more information about the relevant anatomy, see Female Urethra Anatomy, Female Urinary Organ Anatomy, Male Urethra Anatomy, and Male Urinary Organ Anatomy.

Contraindications

Contraindications for placement of an artificial urinary sphincter include the following:

  • UTI: All candidates for an artificial urinary sphincter should be screened for UTI preoperatively.

  • Recurrent urethral strictures or diverticula

  • Small bladder capacity or poor compliance (However, some patients with this contraindication are candidates for artificial urinary sphincter with concomitant or preoperative augmentation cystoplasty.)

There are also many relative contraindications, such as the following:

  • Grade 2 or higher vesicoureteral reflux should be corrected before artificial urinary sphincter placement.

  • Recurrent disease (eg, stone disease, bladder or ureteral tumors) that requires retrograde endoscopic instrumentation is a relative contraindication. Such instrumentation can predispose to cuff erosion in patients with an artificial urinary sphincter.

  • Bladder neck contractures (a not uncommon complication of prostate surgery) should be treated first, and cystoscopy or retrograde urethrography should be performed at least 3 months afterward to ensure continued patency of the bladder neck before proceeding with artificial urinary sphincter placement.

  • Uncontrolled detrusor overactivity: In patients with significant mixed incontinence, controversy exists about which should be treated first–the bladder or the outlet. One review of post-prostatectomy patients treated with AUS showed that 29% of patients with preoperative OAB had resolution of their OAB; on the other hand, the de novo OAB rate was 23%. All patients were treated with anticholinergics.[2]

 

Workup

Laboratory Studies

See the list below:

  • Urinalysis and urine culture: The possibility of UTI should be ruled out before implanting an artificial urinary sphincter. The presence of a UTI is a contraindication to artificial urinary sphincter placement.

  • Serum white blood cell (WBC) count: Systemic leukocytosis should be treated before surgery.

  • Serum creatinine: The patient should have relatively normal and stable renal function before AMS 800 artificial urinary sphincter placement.

Imaging Studies

See the list below:

  • Voiding cystourethrography

    • This test is optional but can be used to assess bladder neck and urethral function (ie, internal, external sphincter) during the filling and voiding phases.

    • Voiding cystourethrography (VCUG) allows radiographic observation of an incompetent bladder neck and coincident leakage during Valsalva maneuvers. VCUG is performed most often at the time of videourodynamics.

    • Grade 2 or higher vesicoureteral reflux on VCUG should be corrected before placement of the artificial urinary sphincter because the sphincter can exacerbate reflux.

Other Tests

See the list below:

  • Voiding diary: A voiding diary is a daily record of a patient's bladder activity. The diary is an objective documentation of a patient's voiding pattern, incontinent episodes, and any inciting events associated with urinary incontinence. Although not critical, a properly logged voiding diary can provide stronger documentation of the degree of incontinence than the standard question regarding number of pads per day used by the patient. Keeping track of fluid intake and urine output in the diary can give further insight into the patient's incontinence and identify patients who can improve their incontinence with less invasive interventions, such as timed voiding. It can also help identify patients with associated problems such as polyuria.

  • Physical examination: All patients with incontinence should undergo a complete physical examination. Women with incontinence must undergo a full pelvic examination to note pelvic floor weakness (eg, cystocele, rectocele, enterocele), urethral hypermobility, urethral or vaginal lesions, or uterine or adnexal masses.

  • Pad test: Patients with classic intrinsic sphincteric dysfunction present to the office with a diaper or a pad in place. An adult male with a damp or wet pad inside his underwear has urinary incontinence unless proven otherwise. It is important to ask patients not only how many pads they use in a day but also how wet those pads get (from lightly dampened to soaked).

  • Standing cough stress test: The patient stands upright with feet shoulder width apart. Place a large towel under the patient's feet or a small trash can between the patient's feet to catch the flow of urine. Instruct the patient to perform the Valsalva maneuver and to cough in gradients (ie, mild, moderate, severe). Observable urine leakage in this position constitutes a positive test result. If the bladder is empty at the time of the Valsalva maneuver or cough, the test result is falsely negative. An excellent alternative is to leave the bladder full following cystoscopy and have the patient stand over a towel. Ask the patient to perform the Valsalva maneuver, and watch for a leak. Following this task, see if the patient can maintain continence while walking to the restroom.

  • Urodynamic studies

    • Urodynamics is a means of evaluating the bladder capacity, compliance, abdominal leak point pressure, presence of phasic contractions, and pressure-flow relationship between the bladder and the urethra.

    • Simple urodynamics involves noninvasive uroflow, postvoid residual (PVR) urine volume, and single-channel cystometrography (CMG). A single-channel CMG (simple CMG) is used to assess the first sensation of filling, fullness, and urge. Bladder compliance and the presence of uninhibited detrusor contractions (eg, phasic contractions) can be noted during this filling CMG.

      • A filling CMG is used to assess the bladder capacity, compliance, and presence of phasic contractions.

      • Most commonly, liquid filling medium is used.

      • An average adult bladder holds approximately 450-500 mL of urine.

      • During the test, provocative maneuvers, such as coughing, handwashing, sitting on the commode for 1 full minute, and heel jouncing, may help unveil bladder instability.

      • Insert a catheter (connected to a special computer) into the bladder for a single-channel CMG. Information recorded by the computer is interpreted.

      • Eyeball cystometry does not require special computers. Perform bedside cystometry by inserting a catheter into the bladder, hanging the irrigant bag at a predetermined height (eg, 100 cm water), and observing the fluctuation of the meniscus within the water chamber during uninhibited detrusor contractions. Eyeball cystometry can also be performed with a flexible cystoscope being used as the connection tubing, allowing simultaneous cystoscopy.

    • Multichannel urodynamic studies are more complex than simple urodynamic studies and can be used to obtain additional information, including a noninvasive uroflow, PVR, filling CMG, abdominal or Valsalva leak point pressure (ALPP or VLPP), voiding CMG (pressure-flow study), and electromyography (EMG). Water is the fluid medium used for multichannel urodynamics.

      • A voiding CMG (pressure-flow study) simultaneously records the voiding detrusor pressure and the rate of urinary flow. This is the only test that can be used to assess bladder contractility and the extent of a bladder outlet obstruction. Pressure-flow studies can be combined with a voiding CMG and videourodynamic study for complicated cases of incontinence. Note that most adult men normally void with detrusor pressures (PdetQmax) of 40-80 cm water. However, pressures of 20-30 cm water or lower are considered to be within the reference range if uroflow (Qmax) is within the reference range or high.

      • Abdominal (Valsalva) leak point pressure (ALPP) measurements allow clinicians to classify stress urinary incontinence into type I, type II, and type III, or type II and III in combination. ALPP of 0-60 cm water is classified as type III stress urinary incontinence (ie, intrinsic sphincteric dysfunction). In short, the outlet is so weak that even low pressures can overcome the resistance and produce incontinence. ALPP of 60-90 cm water is classified as type II/III stress urinary incontinence (ie, combination of urethral hypermobility and intrinsic sphincteric dysfunction). ALPP of 90-120 cm water is classified as type II stress urinary incontinence (ie, urethral hypermobility). ALPP greater than 120 cm water is classified as type I stress urinary incontinence.

      • ALPP should be measured when the bladder is half full (eg, 250 mL), and both the Valsalva and coughing maneuvers should be performed. Initially, instruct the patient to bear down in gradients (ie, mild, moderate, severe) and then note the ALPP as the lowest intravesical pressure (Pves) at which leakage is observed.

      • If Valsalva maneuvers fail to produce the desired response, instruct the patient to cough in gradients (ie, mild, moderate, severe) to obtain the ALPP. The lowest intravesical pressure (Pves) at which leakage is observed is the ALPP. The ALPP obtained with the Valsalva maneuver is more accurate than the cough-induced ALPP. However, both techniques should be used if Valsalva maneuvers fail to manifest stress urinary incontinence.

      • Alternatively, both Valsalva and cough-induced ALPP may be repeated by increasing the bladder volume in 100-mL gradients. Increasing the bladder volume reportedly increases the sensitivity of detecting ALPP.

      • Obtaining ALPP in male stress incontinence (ISD) is optional because men with type III stress incontinence, by definition, have ALPP less than 60 cm water.

    • The most sophisticated study is videourodynamics, which is the leading standard in the evaluation of a patient with incontinence. In this study, the following are obtained: noninvasive uroflow, PVR, filling CMG, ALPP, voiding CMG (pressure-flow), EMG, static cystography, and VCUG. The fluid medium used for videourodynamics is radiographic contrast.

    • Performing urodynamic studies

      • Instruct the patient to arrive at the urodynamic laboratory with a relatively full bladder. Note that patients with ISD have a low-volume or empty bladder because of continuous incontinence. Perform a noninvasive uroflow and PVR.

      • Some physicians perform cystoscopy at the same time as urodynamics, although the two can be done separately. Place a urodynamic urethral catheter, rectal tube, and EMG electrodes.

      • Rotate the patient to a standing or sitting position and equalize transducers. Commence bladder filling using room-temperature water or contrast (Conray). Cold water may evoke false-positive detrusor contractions (phasic contractions). Fill the bladder at a medium rate (eg, 50 mL/min). Assess the first sensation of filling, fullness, and urge. Note bladder compliance and mark the presence of uninhibited detrusor contractions.

      • When the bladder fills to 250 mL, measure the ALPP. Instruct the patient to perform the Valsalva maneuver in gradients (ie, mild, moderate, severe) followed by cough (ie, mild, moderate, severe). Observe the urine leakage fluoroscopically and by direct inspection.

      • Following the ALPP measurements, finish the filling CMG to completion. When the patient has a strong desire to void, perform a voiding CMG (pressure-flow study). At this point, note urodynamic parameters, such as maximal flow rate (Qmax) and detrusor pressure at maximal flow rate (PdetQmax).

      • During the voiding CMG, note the activity of the EMG electrodes and VCUG for possible detrusor sphincter dyssynergia (DSD). The presence of DSD is confirmed by increases in EMG activity during detrusor contraction or closure of the external sphincter on VCUG during voiding.

      • After the patient voids to completion, the videourodynamic study is complete. The patient is informed about the findings on urodynamic studies and is sent home.

    • Uroflow rate: The uroflow rate is a screening test used mainly to evaluate bladder outlet obstruction. The uroflow rate is the volume of urine voided per unit of time. Maximal flow rate (Qmax) greater than 15 mL/s may be considered within the reference range. Low uroflow rates (< 15 mL/s) may reflect urethral obstruction, a weak detrusor, or both. This test alone cannot be used to distinguish between obstruction and a poorly functioning detrusor. Patients with intrinsic sphincteric dysfunction demonstrate uroflow rates within the reference range. A voided volume of 150 mL is a generally accepted minimum for accurate uroflowmetry, and variations of 2-4 mL/s in a single patient are common, so more than one measurement may be required. A maximum flow rate of less than 15 mL/s is usually considered abnormal but must be considered within the context of the patient's clinical presentation.

    • Postvoid residual urine volume: This measurement is a part of the basic evaluation for urinary incontinence. Healthy men usually have a PVR urine volume of less than 100 mL. If the PVR volume is high, the bladder may be atonic or the bladder outlet may be obstructed. Both of these conditions cause urinary retention and overflow incontinence. Patients with intrinsic sphincteric dysfunction have minimal PVR urine volume.

    • Electromyography: EMG helps ascertain the presence of coordinated or uncoordinated voiding. Failure of urethral relaxation during a bladder contraction results in uncoordinated voiding (ie, DSD). EMG is not necessary for evaluation of men who are incontinent after prostatectomy; however, EMG is used in combination with multichannel urodynamic studies and is important in the evaluation of neurogenic bladders.

  • Cystoscopy

    • Cystoscopy is optional in female patients. However, it may uncover bladder lesions (eg, stitch in the bladder, bladder cancer, bladder stone, vesicovaginal fistula) that, although uncommon, would remain undiagnosed based on urodynamics findings alone. The bladder can be left full following cystoscopy to perform the standing cough test.

    • In male urinary incontinence, cystoscopy should be performed more routinely, because a visual inspection of the urethra helps establish the presence of urethral stricture or diverticulum, bladder neck contracture or anastomotic stricture, or gross evidence of poor urethral coaptation and closure. It is important to examine the external sphincter both with and without the flow of irrigant to ascertain the degree of sphincter incompetence.

    • In general, cystoscopy is also indicated for patients reporting persistent dysuria, storage symptoms, or hematuria. Obvious causes of bladder overactivity, including cystitis, stone, and tumor, can be easily diagnosed. Patients with a history of pelvic radiation may have findings of radiation cystitis on cystoscopy. This information is important in determining the etiology of the incontinence and may influence treatment decisions.

  • In the absence of videourodynamics, the clinician may obtain adequate information regarding male incontinence from (1) noninvasive uroflow and PVR and (2) simple cystometry in combination with cystoscopy.

 

Treatment

Medical Therapy

No known reliable medical therapy exists for postprostatectomy male stress incontinence. Alpha agonists have not been demonstrated to be helpful in correcting male intrinsic sphincteric dysfunction. Periurethral bulking agents, including collagen injections, have a long history of use in incontinence. They have been effective in improving stress incontinence symptoms, but problems with agent migration or absorption have limited their long-term efficacy. Overall improvement varies from 35-70%, and multiple injections are often required. Nonetheless, collagen injections present a less-invasive alternative for patients who are wary of an implanted device or are poor candidates for the artificial urinary sphincter.

For women with intrinsic sphincteric dysfunction, estrogen therapy, alpha agonists, or both have provided some improvement in symptoms. Periurethral collagen injections are most effective for women with intrinsic sphincteric dysfunction, producing cure rates that last as long as 1 or 2 years. Although the efficacy of periurethral injection therapy is better in women than in men, the treatment does not produce lasting cure, for the same reasons.

Duloxetine is a serotonin and norepinephrine reuptake inhibitor that is indicated for depression and has been shown to increase resting urethral pressure and may, therefore, decrease stress incontinence in women. Clinical trials for use of duloxetine in postprostatectomy patients are currently in progress. Duloxetine is not yet approved by the US Food and Drug Administration for treatment of incontinence in men or women.

Other noninvasive options include Kegel exercises, which should be taught to all women with genuine stress incontinence and men with postprostatectomy incontinence. In addition, for men with incontinence, there are external continence clamps that are applied to the penile urethra; however, although these clamps are noninvasive and easily discontinued, they demonstrate limited efficacy and are uncomfortable for many men to wear.

In short, all noninvasive interventions for stress incontinence caused by intrinsic sphincteric dysfunction are less effective than surgical interventions.

Surgical Therapy

Male Suburethral Slings

Male suburethral slings are discussed below.

InVance male sling

In 2000, American Medical Systems (AMS) launched the InVance male suburethral sling, a surgical option for men with intrinsic sphincteric dysfunction (which usually occurs after radical or transurethral prostatectomy).

The male sling is not as effective as the artificial urinary sphincter and is therefore indicated only for patients with mild-to-moderate stress incontinence due to intrinsic sphincteric dysfunction and patients with significant incontinence who are not candidates for the artificial urinary sphincter.

Patients who continue to have significant incontinence after placement of the suburethral sling may still be candidates for an artificial urinary sphincter (ie, prior placement of a sling is not a contraindication to placement of the artificial urinary sphincter).

AdVance male sling

In 2004, AMS launched the AdVance male suburethral sling, which is a transobturator suburethral sling placed perineally. The AdVance sling is indicated for men with mild to moderate stress incontinence, as is the InVance male sling.

In establishing candidacy for the AdVance sling, demonstration of residual sphincter function is necessary preoperatively. Urethroscopy can be used to evaluate function. In this study, the patient is asked to voluntarily coapt his sphincter under direct vision. Alternatively, the ability for the patient to voluntarily stop and start their urinary stream demonstrates residual sphincter function.

The AdVance sling has shown excellent short-term results.[3] As with the InVance, patients in whom AdVance sling placement fails are still candidates for the artificial urinary sphincter.

Coloplast Virtue

Coloplast launched the Virtue Male Sling in Summer 2009. Also placed through a perineal approach, the Virtue has four arms, two of which are passed prepubic, and two through the obturator foramen. It has been described as a hybrid device, offering urethral mobilization through the transobturator arms, and urethral compression through the prepubic arms.

The AMS 800 device

The AMS 800 artificial urinary sphincter is the most commonly used device and is the criterion standard for the treatment of incontinence caused by intrinsic sphincteric dysfunction. It is composed of a pressure-regulating balloon, an inflatable cuff, and a control pump (see image below). The balloon has a dual function as a pressure regulator and a fluid reservoir.

The artificial urinary sphincter (AMS 800) is comp The artificial urinary sphincter (AMS 800) is composed of a pressure-balloon reservoir, an inflate-deflate cuff, and a miniature control pump.

Balloon reservoirs come in 5 preset pressures—41-50, 51-60, 61-70, 71-80, and 81-90 cm water. The lowest pressure required to close the urethra is used. Balloon reservoirs are typically placed in the lower abdomen. For uncomplicated bulbar urethral cuffs, the most commonly chosen balloon reservoirs are the ones with preset pressures of 51-60 and 61-70 cm water. For bladder neck cuffs, the balloon reservoir with pressures of 71-80 cm water is chosen because higher pressures are necessary to occlude the bladder neck. Patients with prior radiation or surgical changes that present a higher risk of erosion may benefit from a 51-60 cm water reservoir. In addition to a lower pressure reservoir, some advocate transcorporal cuff placement in patients with a history of radiation therapy.[4]

The inflatable cuff has a variable length that compresses the urethra or the bladder neck circumferentially. Cuff sizes range from 3.5-11 cm, in 0.5-cm increments. The cuff is placed around the bulbar urethra in adult males. For women and children, the bladder neck is the only site that should be used. The cuff size is based on the circumference of the bladder neck or the bulbar urethra. A properly sized cuff for the bulbar urethra ranges from 4.5-5.5 cm in length. Most commonly, a 4.0-cm cuff is chosen for adult males. For the bladder neck, a 6- to 8-cm cuff is selected in women.

The control pump contains unidirectional valves, a delayed-fill resistor, a locking mechanism, and a deflate pump. The control pump is small and easily concealed within a subcutaneous or dartos pouch in the scrotum or the labia. The delayed-fill resistor is responsible for automatic cuff refilling. The cuff inflation takes 3-5 minutes, although bladder emptying takes less time. A unique feature of this model is the locking mechanism that can keep the cuff deflated for a prolonged period. The locking mechanism is a small button located on the side of the control pump.

Mechanics of the AMS 800

The AMS 800 artificial urinary sphincter works on the basis of hydraulic mechanics. The isotonic fluid within the sphincter is transferred from the reservoir to the cuff and vice versa in a unidirectional fashion. When the sphincter is first activated (unlocked), the fluid from the reservoir travels down the pressure gradient to the cuff. The cuff gradually inflates to effectively close the urethra. The inflated cuff causes urine to be stored in the bladder and prevents urine loss. The device works in a semiautomatic fashion, with the cuff remaining closed at all times except when the patient opens the cuff for voiding.

To void, the patient must open the artificial sphincter. The patient manually squeezes the control pump that is located in the scrotum or the labia. When the control pump is squeezed, the fluid in the control pump is sent up to the balloon reservoir. The control pump then automatically reexpands; as it reexpands, it pulls the fluid out from the cuff, which causes the sphincter cuff to deflate. The patient repeats this maneuver 3-4 times until the pump remains flat, which indicates that the cuff is completely empty. At this point, the urine flows freely from the bladder. Urination continues until the bladder is empty. After 3-5 minutes, the fluid from the balloon reservoir automatically flows through a delayed-fill resistor within the pump and down back to the cuff. When the cuff reinflates, the urethra becomes effectively closed and the patient becomes dry.

The locking mechanism (button on the side of the control pump) allows the physician to lock the cuff in an open or closed position. Typically, the AMS 800 device is left locked (deactivated) in an open position at the time of surgical implantation to allow for adequate tissue healing and is unlocked in the physician's office 6-8 weeks after operation. If the patient inadvertently locks the button when the cuff is closed, urinary retention occurs. Conversely, if the button is locked when the cuff is open, persistent incontinence occurs. Patients should be instructed on the locking mechanism to understand and be able to respond to these problems.

Limitations of the AMS 800

Although the AMS 800 artificial urinary sphincter is an extremely reliable prosthesis that is easy to place and the patient satisfaction rate is high after successful implantation, certain limitations exist with this device despite advances in mechanical design. Mechanical malfunctions (ie, cuff leak, defective pump) and surgical problems (ie, pump migration, cuff migration, improper cuff size) require reoperation and sphincter revision. Urinary incontinence may arise from improper usage, fluid leakage, pressure atrophy, or cuff erosion. Urinary retention may occur as a result of particle obstruction or a tube kink in the system.

  • Silicone composition: The AMS 800 is composed of permeable silicone elastomer. Although relatively inert and resistant to body fluids, silicone deteriorates and loses tensile strength over time. Because the cuff is permeable, fluid escapes over time, with a resultant decrease in closing cuff pressure. The constant rubbing together of the 2 silicone components can lead to thinning of the silicone elastomer and exacerbate fluid leakage.

  • The hydraulic system: The balloon, cuff, pump, and connecting tubings are filled with iso-osmotic solution. Either isotonic sodium chloride solution or radiocontrast is used. The tonicity of the contrast is approximately 290-310 mOsm/L, which is similar to that of human intracellular and extracellular fluid. The use of hypo-osmolar or hyperosmolar fluid causes sphincter malfunction from osmotic fluid shifts.

  • Pressure-regulating balloon: The fluid volume of the pressure-regulating balloon regulates the cuff pressure. A typical balloon reservoir holds 20-22 mL of iso-osmotic fluid. The pressure-volume relationship of the AMS 800 device is very narrow and sigmoid-curve shaped. Small volume changes (eg, 2 mL) decrease the pressure characteristics; when the volume decreases to below 14 mL, the pressure decrease is precipitous. A common cause of postactivation incontinence is fluid loss from the pressure-regulating balloon. The patient notices that the number of squeezes to deactivate the pump has decreased or the pump does not refill and remains flat. The incidence of balloon leak responsible for sphincter malfunction has been reported to be as high as 13% in some series.

  • Inflatable cuff: A common problem leading to delayed or persistent incontinence is fluid loss caused by a wear defect in the cuff. The most common site of fluid leak is the lower surface of the cuff. In 1983, the inner surface of the cuff was reinforced with a layer of fluorosilicone gel to prevent friction between 2 leaflets. With this modification, the cuff leak rate decreased from 56% to 1.3%.

  • Connecting tubing: A short tube length may disrupt connecting junctions, causing a fluid leak or pulling up the control pump into the inguinal area, making device manipulation difficult. Excess tube length may lead to kinks, obstructing the system and causing urinary retention. Kinks are rare after 3 months of device implantation. In the past, tube kinks were the most common mechanical cause for surgical revision. With the advent of reinforced kinkproof tubing, no mechanical failures have been reported. However, tube kinks still may occur from tailoring connecting tubes to an improper length during the implant procedure.

  • Control pump: The control pump is cosmetically appealing because of its small size. Its small size can be a handicap, however, because some patients may have difficulty manipulating the pump. Labial or scrotal hematomas may displace the pump into an unfamiliar location. The pump may rotate upon itself and become kinked. Migration of the pump into the inguinal region may cause failure to deflate the cuff.

  • Locking mechanism: A major technological advancement of the AMS 800 is its locking mechanism. The disadvantage is that activating and deactivating the cuff using the locking mechanism is not always easy. The locking mechanism lacks a tactile feedback mechanism, making it difficult to tell if locking has occurred. Before locking the cuff, one must be sure that some fluid remains in the pump chamber. If the pump chamber is totally flat and empty, unlocking (activating) the cuff in the standard fashion is impossible. If this occurs, squeezing the sides of the locking button (located immediately above the pump chamber) allows the fluid to return to the pump chamber by circumventing the delayed-fill resistor.

Preoperative Details

During the informed consent, potential complications unique to placement of the AMS 800 should be discussed. Potential complications include urethral injury, bladder injury, rectal injury, mechanical failure, labial or scrotal hematoma, device infection, urinary retention, tissue atrophy, and persistent stress incontinence. The relative risk of these complications is described under Complications. Many of these complications require reoperation, and the possibility of surgical revision at a future date should therefore be discussed. In addition, patients should be cautioned that the procedure will be terminated in the event of a urethral, bladder, or rectal injury because of the risk of infection. Finally, patients should understand that they will remain incontinent during the healing process, until the device is activated 4-8 weeks after operation.

The operating room staff and surgeon should be familiar with the device, the equipment needed, and the surgical steps of the procedure. The surgeon and/or the operating room staff should observe the AMS 800 prosthesis implantation procedure before surgery.

Prophylactic broad-spectrum antibiotics (usually an aminoglycoside [eg, gentamicin] and vancomycin) should be administered. An alcohol-based preparation is preferred because it offers better control of the typical offending bacteria. Magera et al reported that patients who scrubbed preoperatively with 4% chlorhexidine were 4 times less likely to experience perineal colonization during surgery.[5] More recently, chlorhexidine-alcohol preparation has been shown to reduce the presence of coagulase-negative Staphylococci from the surgical site better than povidine-iodine in a randomized trial.[6]

Intraoperative Details

Once the patient is in the operating room, the abdomen and genitalia are shaved. Following the shave, the area is scrubbed for 10-15 minutes. For bulbar urethra cuff placement, the patient is placed in the dorsal lithotomy position. The patient is draped for both a perineal and an abdominal incision. The use of barrier drapes reduces the risk of contamination with skin flora.

A plastic-draped Mayo stand is used as a station for handling and filling of prosthetic components. The surgical setup should include a broad-spectrum antibiotic solution for irrigation. The antibiotic solution and the filling solution should be kept separate from each other. Components should not have contact with paper or cloth drapes. Submerge the filled components in a storage basin containing sterile sodium chloride solution until they are ready for implantation.

Silicone components actively attract dust and lint. Glove powder that enters the tubing may block the pump valves. Surgeons should wash their gloves before making the tubing connections. The operative technique of placing the urethral cuff is described below (see images).

The patient is placed in the dorsolithotomy positi The patient is placed in the dorsolithotomy position. A perineal incision has been made below the scrotum. The Colles fascia is being dissected off.
The bulbocavernosus muscle has been dissected off. The bulbocavernosus muscle has been dissected off. The bulbar urethra is exposed.
The right-angle clamp is passed behind the bulbar The right-angle clamp is passed behind the bulbar urethra.
The measuring tape is passed around the bulbar ure The measuring tape is passed around the bulbar urethra. The bulbar urethra measures 4.5 cm; thus, a 4.5-cm cuff is chosen for implantation.
The artificial urinary sphincter cuff is passed—th The artificial urinary sphincter cuff is passed—the tab end first—around the urethra. The cuff is snapped into place.
The tab of the artificial urinary sphincter cuff i The tab of the artificial urinary sphincter cuff is rotated dorsally.
The cuff is seated in an excellent position. The t The cuff is seated in an excellent position. The tubing from the cuff is passed up to the suprapubic wound, where it is connected to the control pump.
The perineal incision is being closed. The Colles The perineal incision is being closed. The Colles fascia is closed. The skin is closed next.
The balloon reservoir has been placed into the sub The balloon reservoir has been placed into the subrectus space, and the control pump has been inserted into the right hemiscrotum because the patient is right-handed. The cuff, pump, and reservoir are all connected.

See the list below:

  • Balloon reservoir placement: Make a suprapubic incision. A midline or transverse incision is made. Divide the rectus fascia. Spread the linea alba to reach the prevesical space. Use blunt dissection to create a space for the balloon. Fill the balloon with 22 mL iso-osmotic filling solution, aspirate the air, and evacuate the fluid from the balloon. Clamp the tubing and position the balloon in the prevesical space. Route the tubing through the rectus fascia to the abdominal incision.

  • Bulbous cuff placement

    • Place a 12F or 14F Foley catheter. Make a midline perineal incision. Identify the bulbocavernosus muscle. The bulbocavernosus muscle is either split in the midline or left intact according to surgeon preference. Use a combination of scissor dissection and a right-angle clamp to dissect around the bulbar urethra under direct vision. Dissect out a 2-cm plane posteriorly around the urethra to accommodate the cuff. The most common site of urethral injury during artificial urinary sphincter placement is at the 12-o'clock position, where the urethra is adherent to the septum of the corpora cavernosa. Encircle a Penrose drain around the urethra and use it as a retractor to facilitate urethral dissection. Exchange the Penrose drain for a measuring tape. The urethral measuring tape is placed around the urethra at the site where the cuff is to be implanted. The measuring tape must fit snugly but without constricting the urethra. Remove the urethral catheter before measuring the urethra.

    • Select the cuff size that corresponds to the measured length. The cuff is prepared for implantation by injecting the filling solution into the cuff, aspirating all of the air, and then evacuating the fluid from the cuff. Place the cuff around the urethra. Pass the cuff, tab first, under the urethra. Snap the cuff into place. Route the cuff tubing suprapubically through a subcutaneous tunnel to the abdominal incision. If it was divided, reapproximate the bulbocavernosus muscle over the cuff followed by Colles fascia. Close the perineal incision.

    • A transverse scrotal, single-incision approach has been described,[7] with results comparable to those of the classic two-incision approach. In this operation, the transversalis fascia is pierced to place the reservoir in the paravesical space. Alternatively, an approach through the inguinal ring has been described that does not pierce the fascia, but this approach poses a risk of iatrogenic hernia. Other authors have corroborated the success of this procedure.[8] However, in a recent comparative study, Henry et al (2008) found better overall continence rates and a lower risk of revision surgery with the classic perineal approach.[9]

  • Pressurizing the system

    • To pressurize the cuff, the cuff tubing and the balloon tubing are temporarily connected with a straight connector. Remove the catheter. Flush the tubing ends to remove all debris. Fill the balloon with 22 mL of iso-osmotic filling solution. Temporarily connect the cuff tubing and the balloon tubing by using a straight connector. This allows the cuff to pressurize. Wait 10-30 seconds. Clamp the cuff tubing and the balloon tubing with silicone-shod hemostats and remove the connector. Remove the hemostat and aspirate all of the remaining fluid from the balloon. Refill it with 20 mL of filling solution. Clamp the tubing with silicone-shod hemostat until the final connection is made. This 2-step filling compensates for the potential pressure atrophy.

    • Some surgeons feel that pressurizing the cuff and the balloon reservoir before making the final connection is optional rather than truly necessary. Many surgeons instead opt to fill the pressure reservoir with 23 mL of isotonic sodium chloride solution (ie, 22 mL for the balloon and 1 mL for the cuff = 23 mL total) and connect the tubing after all components (ie, balloon, cuff, pump) have been implanted. By not pressurizing the cuff, the operation is simplified without compromising the efficacy of the sphincter function.

  • Pump implantation: To implant the control pump in the scrotum, use blunt dissection to create a dependent subdartos pouch. The control pump should be placed on the patient's hand-dominant side. From the abdominal incision, dissect out the chosen hemiscrotum for pump placement. After filling the pump with filling solution, replace it in the scrotum. Place the pump in the most dependent part of the scrotal pouch, making sure that it is palpable and the locking button faces outward. The pump tubing should be above the rectus muscle and fascia in the abdominal incision.

  • Connections: After the components are placed, trim the excess tubing. Connect the ends of the tubing by using the sutureless Quick connectors. Suture-tie connectors are used for revision surgeries. Connecting tubings should lie above the rectus fascia.

  • Checking the device: After the connections, the sphincter is cycled. The device should be cycled 2 or 3 times to ensure good mechanical function. Adequate urethral coaptation may be evaluated via retrograde perfusion sphincterometry or flexible cystoscopy, but this is optional. After confirming that the sphincter is working properly, the cuff is locked in an open position (deactivated). To deactivate the device, the pump is squeezed and released several times to empty the cuff. When the cuff has refilled so that a slight dimple is palpable, the deactivation button is pushed to lock the cuff open. Be careful not to leave the pump completely empty, as this can greatly complicate activating the device later. During the healing process, the cuff must remain locked in an open position. The abdominal incision is closed. A small Foley catheter (14F) is optional but recommended for the immediate postoperative period.

Postoperative Details

Intravenous antibiotics are continued until discharge. The Foley catheter is removed the day of or the day after the surgery according to surgeon preference. Postoperative antibiotics are prescribed at the surgeon's discretion.

Immediately after implantation, a 4- to 8-week deactivation period allows healing. The cuff is left open in a locked state. Postoperatively, the patient experiences no change in stress incontinence until the sphincter is activated. Thus, some protection must be used in the form of pads, external condom drainage, or intermittent catheterization during the healing phase.

Intermittent catheterization is not a contraindication to an artificial urinary sphincter as long as the cuff remains deflated. Those with bladder-neck cuff placement may perform self-catheterization without risk to the cuff and the underlying tissue. However, patients with bulbous urethral cuffs are at higher risk of injury from prolonged indwelling, rather than intermittent, catheterization.

Follow-up

The patient is instructed not to manipulate the sphincter for 6 weeks. The first postoperative clinic visit is in 1-2 weeks, at which time the abdominal and perineal incisions are inspected for skin integrity and wound infection. At 6-week follow-up, the sphincter is activated by applying a firm, forceful squeeze to the control pump. The patient is instructed on the proper use of this device by the physician, and, if available, a video presentation is shown to the patient.

All patients require direct visual demonstration of sphincter use after activation. Some patients are more adept than others in learning how to operate the pump. Improper cuff use is the most common cause of postactivation urinary incontinence. Patients experience incomplete emptying and overflow incontinence if the cuff is not opened properly. Difficulty manipulating the pump leads to inadequate cuff deflation and sphincter malfunction.

If these patients are treated in the emergency department or if they require hospitalization for a medical problem, they are instructed to inform their treating physician that they have an artificial urinary sphincter. Passage of a catheter or any other instrument through the urethra without deflating the cuff and deactivating the device first may result in sphincter injury. Many physicians and health care providers are not familiar with the artificial urinary sphincter; therefore, educating patients on how to deactivate the sphincter can be invaluable. AMS provides patients a card to carry in their wallets that identifies them as having an implanted artificial urinary sphincter.

Some surgeons advocate nighttime deactivation of the sphincter. For patients willing to wear pads or a diaper at bedtime, deactivating the sphincter overnight provides a daily period when there is no cuff pressure on the urethra. These patients may therefore reduce the risk of or delay the onset of urethral atrophy and recurrent incontinence. Other surgeons believe this approach to be ineffective and to impose unnecessary nighttime incontinence on the patient. One study comparing the two approaches demonstrated a trend toward decreased atrophy with nighttime deactivation, but the study lacked sufficient power and did not achieve statistical significance.[10]

Patient education

For excellent patient education resources, see eMedicineHealth's patient education article Cystoscopy.

Complications

See Limitations of the AMS 800 for a discussion of device-related complications.

Intraoperative complications

See the list below:

  • Pressure-regulating balloon: The balloon reservoir is placed intra-abdominally or in an extraperitoneal prevesical space (space of Retzius). For patients with prior pelvic surgery, scars and adhesions increase the risk of bladder perforation. The intraoperative use of a catheter keeps the bladder decompressed and greatly reduces the risk of bladder injury. Iatrogenic peritoneotomy and bowel injury have been reported. If bowel injury occurs, the implantation must be abandoned.

    • Inflation cuff

      • Urethral injuries result from direct perforation or tissue necrosis due to thermal injury. Most urethral injuries occur at the 12-o'clock position, where the urethra is adherent to the corpus cavernosa. This is the most difficult site of dissection. Unrecognized urethral injuries result in early cuff erosion and incontinence. Bulbar placement in a prepubescent male should not be performed, because the tissues are thin and the risk of erosion is high. Cuff implantation at the bladder neck is more difficult than at the bulbar urethra. Bladder neck implantation of AUS via a robotic-assisted laparoscopic approach has been performed in a small series of adult men. This avoids the morbidity of open abdominal surgery, although long-term success rates are as of yet unclear.[11]

      • In females, a correct plane between the bladder neck and the vagina must be identified to avoid injury to the urethra, vagina, and rectum. To aid in the cuff placement, the use of a Cutter clamp and cystoscopy have been used. Some surgeons open the bladder before dissection to visualize ureteral orifices and the bladder neck. Vaginal injuries are closed primarily. If a rectal injury occurs, the procedure must be abandoned.

    • Connecting tubing: The presence of particulate matter in the tubing increases the risk of sphincter malfunction. A few air bubbles entering the system are harmless because they are absorbed; however, aggregation of air bubbles into an air lock can obstruct the pump. Blood clots can also obstruct the connecting tube or the valves in the pump. Care is therefore taken to prevent entry of particulate matter into the system by flushing the air bubble or blood clot out of tubing during surgery.

Postoperative complications

Postoperative complications can be described as mechanical or nonmechanical. The reported reoperation rate for the artificial urinary sphincter is 17-35%, with about 50% of these cases caused by mechanical complications and 50% by nonmechanical complications. Despite these reoperation rates, the success rate for secondary artificial urinary sphincter operations is high and patient satisfaction excellent.

Mechanical

Mechanical failure of the artificial urinary sphincter is most commonly caused by loss of fluid from the system. It can also occur because of obstruction of flow due to debris, airlock, blood, or crystallized material. Care at the time of device filling and implantation to avoid air entrapment and presence of debris can reduce the risk of several of these problems. Obstruction due to kinking is now rare because of the introduction of kink-resistant tubing in the late 1980s.

The overall life expectancy of the artificial urinary sphincter is 10 years, with a 5-year device survival rate of 75%.

Nonmechanical

See the list below:

  • Infection

    • Because the artificial urinary sphincter is a synthetic device, it is a risk factor for bacterial infection. The overall risk of infection is reported to be 2-3% for initial artificial urinary sphincter placement.

    • The most common infecting organisms are Staphylococcus epidermidis and Staphylococcus aureus. Gram-positive infections most commonly occur because of intraoperative contamination, and the gram-positive organisms are the most likely causative agents of early device infection. Late infections are more likely to be caused by gram-negative uropathogens, including Proteus species, Pseudomonas species, Escherichia coli, Serratia species, Corynebacterium, and Enterobacter species.

    • Meticulous aseptic techniques must be exercised during sphincter implantation. Perioperative broad-spectrum antibiotic coverage is imperative. The use of barrier drapes reduces potential operative exposure to skin flora. Traffic in the operating room must be minimized.

    • As with all implanted devices, patients should be advised that prophylactic antibiotic coverage is required for dental or other nonsterile procedures.

    • The initial presenting sign of infection is usually pain, often located at the scrotal pump. Later manifestations include fluctuance, warmth, fever, and, eventually, septicemia.

    • Treatment for an infected prosthesis consists of intravenous antibiotics and removal of the device.

    • A rest period of 3-6 months is recommended before proceeding with a new artificial urinary sphincter placement. That said, Mulcahy and colleagues have reported a salvage procedure for a noneroded infected artificial urinary sphincter that is similar to the procedure for an infected penile prosthesis, with a reported success rate of 87%.[12]

  • Tissue atrophy

    • A common cause of recurrent stress incontinence is loss of cuff compression due to tissue atrophy. Tissue atrophy is the most common cause of nonmechanical failure and has been reported to be the most common cause of surgical revision.

    • Tissue atrophy results from local tissue ischemia around the cuff. Tissue atrophy, in turn, causes poor mucosal coaptation and incomplete urethral occlusion. Patients who were initially continent with the device complain of gradually increasing incontinence over months or even years and report having to squeeze the pump more often to deflate the cuff and void. If the cuff inflates and deflates normally but the patient remains incontinent, tissue atrophy should be suspected.

    • In 1987, a narrow-backed cuff was introduced to decrease the incidence of tissue atrophy. By decreasing the width of the outer leaflet from 2 cm to 1.5 cm while maintaining the inner-leaflet dimension at 2 cm, cuff pressure transmission to the urethra was improved. This modification allowed the inner-cuff leaflet to compress a wider surface area without increasing the occlusive pressure. This new innovative design decreased the reoperation rate from 33-39% in the 1980s to 3-9% in recent series.

    • Another method of retarding tissue atrophy is nocturnal deactivation of the cuff. The cuff is locked in an open position during the night when the patient is asleep. Nocturnal deactivation of the device has been reported to reduce tissue atrophy by decreasing the potential ischemia time. As previously mentioned, however, nocturnal deactivation has critics and proponents, and its benefits have not been conclusively demonstrated.[13]

    • If tissue atrophy occurs, balloon pressure can be increased to the next higher pressure (eg, from 61-70 cm water to 71-80 cm water) to increase the urethral closing pressure. Of course, a higher-pressure balloon will eventually lead to further pressure atrophy of the urethra, and most patients will eventually have some recurrent incontinence. If this fails, the cuff can be downsized to the next smaller size. Unfortunately, most men have the smallest-size cuff placed initially, so cuff-size reduction is not an option. Alternatively, the cuff site may be changed to a different area with better tissue integrity.

    • A well-described approach to recurrent incontinence due to atrophy is the placement of a tandem cuff. The two cuffs are connected with a Y-connector to the remainder of the device. The tandem cuff provides 2 resistors in series and often restores continence and prolongs the life of the device. The tandem cuff is usually placed distal to the original cuff, but it can be placed proximally. The tandem cuff has had excellent results in restoring continence. Some surgeons offer double cuffs at the initial artificial urinary sphincter placement. This has been shown to improve continence rates over the single cuff, but disadvantages include increased cost, longer operative time, and, possibly, increased risk of urethral injury.[14] In a comparison series, O'Connor et al (2008) found no statistically significant benefit between initial single-cuff and double-cuff placement but did find a higher complication rate with the latter.[15]

    • Transcorporal placement can be an effective way to manage urethral atrophy, similar to its use for cuff erosion.

    • Urethral buttressing: A series of 17 men underwent AUS revision for urethral atrophy, in which the atrophied urethra was buttressed with a fibrin-coated collagen fleece to provide "bulking," with a 75% subjective success rate.[16]

    • Overactive bladder syndrome: De novo symptoms of OAB, such as urgency, frequency, nocturia, and urgency incontinence, may develop in up to 23% of patients who did not have these symptoms preoperatively. Those with preoperative OAB will have persistent symptoms in 71% of cases.[2]

  • Cuff erosion

    • One of the most feared complications of the artificial urinary sphincter is cuff erosion. Cuff erosion most commonly occurs within 3-4 months after surgery. Early cuff erosion suggests unrecognized injury to the bladder neck or urethra at the time of surgery. Later causes of erosion are frequently related to catheterization, but erosion may also result from periprosthetic infection or pressure necrosis. The site of erosion can be localized by urethroscopy; cuff protrusion through the urethral mucosa is unmistakably visible. The incidence of cuff erosion has been reported to be 1-3%, which has decreased since the introduction of delayed postoperative activation.

    • Risk factors for cuff erosion include pelvic radiation, excessive cuff pressure, undersized cuff, and retrograde instrumentation (eg, cystoscopy, urethral catheterization) without deactivating the device. Patients who have undergone radiation have a reported erosion rate of 10-20%. The risk of erosion in patients undergoing instrumentation underscores the need for patients to inform emergency department and other physicians that they have an artificial urinary sphincter. In a retrospective study, Diokno (2006) found increased rates of erosion in patients with a history of hypertension, coronary artery disease, radiation, or a prior incidence of cuff erosion.[17] In that study, patients undergoing revision for cuff erosion tended to have good outcomes but were at higher risk for repeat erosion.

    • Efforts to minimize the incidence of cuff erosion include delayed activation, nocturnal deactivation, and use of a low-pressure reservoir. Using a balloon with a pressure of less than 71-80 cm water decreases the risk.

    • Early signs of erosion include gross hematuria, burning perineal pain, perineal or scrotal swelling, swelling at the cuff site, pain at the head of the penis, or even urine leakage from the surgical wound. Erosion may also present simply as recurrent incontinence. Erosion is easily confirmed by urethroscopy. If the erosion is clean and uncomplicated, only the cuff may be removed. If purulent drainage is obvious, removal of all sphincter units is mandatory.

    • Following removal of the cuff or entire device, the urethra should be stented with a catheter for 3-4 weeks to allow healing. A new cuff may be placed 3-6 months later.

    • Women of childbearing age should be warned of the danger of cuff erosion during vaginal delivery. As the baby crowns through the vaginal introitus, the baby's head may compress the cuff against the pubic symphysis, risking cuff erosion. Elective cesarean delivery is advocated by some. Deactivation of the artificial urinary sphincter in the final trimester is recommended to minimize the risk of cuff erosion in this situation, and deactivation during labor is imperative.

    • Transcorporal cuff placement is a relatively recent approach for managing urethral erosion. In this procedure, the cuff is placed not only around the urethra but also through a portion of the corpora cavernosa. This can be done during the initial placement in patients at high risk for cuff erosion (eg, patients who have undergone radiation therapy).[4] Otherwise, this approach should be reserved as a salvage technique in case of erosion, impending erosion, or infection.[18]

    • A study by Bates et al conducted a systematic review and meta-analysis of artificial urinary sphincter placement after radical prostatectomy and external beam radiotherapy. The study found that men receiving radical prostatectomy and external beam radiotherapy appear at increased risk of infection/erosion and urethral atrophy, resulting in a greater risk of surgical revision compared with radical prostatectomy alone.[19]

Troubleshooting the AMS 800

One of the most common complaints associated with the AMS 800 is persistent or recurrent stress incontinence following placement of the device. A careful history and evaluation can often reveal the problem.

  • History and physical examination

    • A history of recent instrumentation, such as catheterization, without prior deactivation of the device suggests cuff erosion.

    • If the number of pump cycles required to void increases, tissue atrophy or fluid leak should be suspected.

    • Difficulty pumping the device may indicate it has been accidentally deactivated.

    • If the patient never achieves continence after activation, the most common problem is too large a cuff or too small a reservoir.

  • Radiographic studies

    • Radiographic evaluation is an important means of troubleshooting a malfunctioning sphincter if contrast is used as a filling medium. Radiography of the lower abdomen is the single most important test to obtain if contrast is used. If isotonic sodium chloride solution is used as fluid medium, radiographic evaluation does not help because silicone components are not radiopaque.

    • Inflate-deflate radiographs are needed to assess the function of the sphincter. When the cuff is open, the pump and the balloon reservoir should contain some contrast, and the cuff should have none. When the cuff is closed, a doughnut-like circumferential ring of contrast should be visible at the cuff site. If the radiographic contrast is absent, a leak has occurred.

  • Urethral pressure profilometry: Urethral pressure profilometry is a nonradiologic test of sphincter function. Withdrawal urethral pressure profilometry should be conducted with the cuff in both inflated and deflated modes. Minimal pressure differential between 2 modes suggests sphincter malfunction.

  • Perfusion sphincterometry: Retrograde perfusion sphincterometry with cystoscopy is a useful test to assess the integrity of the sphincter unit. If time to inflate the cuff is longer than usual or the urethra remains open, either cuff malfunction or tissue atrophy has occurred. At the authors' institution, retrograde perfusion sphincterometry with a flexible cystoscope is performed routinely at the time of sphincter implantation.

  • Electrical conductance testing: Reoperation is often required to service the malfunctioning device. At the time of operation, the use of electrical conductance testing (ohmmeter) aids in identifying the faulty component and the site of the leak. Leaks at connector sites and the balloon stem are excluded first. If the ohmmeter cannot be used to identify the leak site, the pressure in the balloon reservoir can be measured by connecting the tubing to a pressure transducer or by aspirating and measuring the volume in the balloon.

Outcome and Prognosis

American Medical Systems (AMS, the manufacturer of the artificial urinary sphincter) reports the placement of over 94,000 artificial urinary sphincters in men and women. Social continence (1 pad or fewer a day) at 3-year follow-up is achieved in 75-95% of patients. The largest study of artificial urinary sphincter in the literature reports that 90% of patients have a functional artificial urinary sphincter in place at a mean follow-up of 5 years, with a 28% revision rate.[20] The efficacy in women compares with that in men, although there are fewer studies of the efficacy of artificial urinary sphincter in women, largely because women are more often treated with bladder neck suspension and suburethral sling procedures.[21]

A review of 344 women with intrinsic sphincter deficiency treated with an artificial urinary sphincter, followed for a mean of nearly 10 years, demonstrated complete continence in 85.6% and social continence (drops but no pad) in an additional 8.8% of patients. Revision rates and mechanical complications were similar to historical data for men.[22]

The largest single-institution series in children demonstrates a total continence rate of 86% and a revision rate of 25%.[23] Multiple series have supported the safety of concomitant augmentation cystoplasty in patients with intrinsic sphincteric dysfunction and small-capacity or poorly compliant bladders. Another review showed better clinical outcomes in children when the artificial urinary sphincter was implanted before puberty and when preoperative or concomitant augmentation cystoplasty was performed.[24] However, most of these patients still require long-term clean intermittent catheterization.

In patients with neuropathic bladder dysfunction, close urodynamic follow-up is advised after artificial urinary sphincter placement, as urodynamic parameters can change profoundly over time.

The patient satisfaction rate is reported to be 85-95% and depends more on the degree of improvement than on the achievement of total continence. Success is likely in large part influenced by proper patient selection and careful patient education regarding expectations and the possible, even eventual, need for operative revisions.

Future and Controversies

Placement of the AMS 800 is an excellent surgical treatment for men, women, and children with type III stress urinary incontinence. Extremely reliable and durable, the AMS 800 has greatly improved the quality of life in patients with stress urinary incontinence.

Despite recent advances in mechanical design, certain limitations exist with this device. When mechanical malfunctions and surgical problems arise, repeat surgery is often diagnostic and therapeutic. With continued advances in biomechanical engineering, an even better artificial urinary sphincter—one that approaches the function of a biological urinary sphincter—should be forthcoming.

The presence of recurrent bladder neck contracture in combination with postprostatectomy stress incontinence is a difficult problem to treat. Recurrent bladder neck contractures are often treated with incision (direct-vision internal urethrotomy [DVIU]) or transurethral incision of the bladder neck contracture (TUIBNC) followed by implantation of an artificial urinary sphincter. Alternatively, intermittent catheterization is advocated to allow the contracture to "soften up" and stabilize over time. After the contracture has stabilized, an artificial urinary sphincter may be placed. The exact timing of sphincter placement is tailored to each individual, but at least 3 months of patency since the last procedure is generally recommended. Some encouraging results have been reported of concomitant or staged artificial urinary sphincter with stenting (UroLume stent [AMS] of the bladder neck contracture in patients with recurrent, difficult-to-treat stricture).