Indications
The most common indication for placement of an artificial urinary sphincter (AUS) is postprostatectomy incontinence (PPI) from radical prostatectomy for prostate cancer, with 8% to 12% of patients seeking treatment. However, other indications for AUS include stress urinary incontinence secondary to other surgical interventions such as transurethral resection of the prostate and sphincterotomy, injury to the sphincteric mechanism caused by trauma, and neurogenic bladder. In addition, AUS is rarely used in women with SUI.
American Medical Systems initially developed the AUS in 1973, and it has undergone multiple modifications to allow for longer life and improved continence rates to the current model AMS 800. The AUS has long-term data, with patient satisfaction rates of 72% to 90% at 23.4 months to 7.7 years of follow-up. Social continence (0–1 pads per day) has been shown to be 97% at 23.4 months, with long-term rates of 54% to 77% at follow-up of 6.8 to 7.7 years.
Although other procedures are used to treat incontinence in both males and female patients including periurethral bulking agents, slings (synthetic or facial), and continence balloons, the AUS remains the gold standard for the management of moderate to severe stress urinary incontinence in male patients.
Preoperative Evaluation
Preoperative evaluation is an extremely important step before placement of an AUS. Patients with PPI may see continued improvement of incontinence for up to 2 years after surgery with improvement from 92% to 98.5% at 12 and 24 months, respectively. For this reason, evaluation is usually delayed until at least 12 months have passed since the patient’s prostate surgery; however, there are no data identifying the optimal assessment time. Initial evaluation with a history, physical examination, demonstration of stress incontinence, urinalysis with culture, and postvoid residual is appropriate. Voiding diaries, pad tests, and incontinence questionnaires may also be useful. It is very important to evaluate the patient’s manual dexterity and mental status to assess the patient’s ability to use the control pump before proceeding with AUS placement.
Cystoscopy is performed to evaluate the health of the urethral tissue and to rule out a urethral stricture or bladder neck contracture. The presence of a stricture or bladder neck contracture requires intervention and resolution before implantation of an AUS. Urodynamics can be considered to evaluate for detrusor function, bladder compliance, and detrusor overactivity, especially when the etiology of incontinence is unclear.
Preoperatively, a urine culture should be formed; if the result is positive, the patient should be treated, and negative culture should be obtained before surgery. Perioperative antibiotics should include coverage for skin and urinary pathogens to avoid colonization of the implant. The present AUA guidelines recommend coverage with an aminoglycoside plus a first- or second-generation cephalosporin or vancomycin. Alternatives include ampicillin–sulbactam, ticarcillin–clavulanate, or piperacillin–tazobactam. Parts of the implant are impregnated with InhibiZone, which consists of rifampin and minocycline. InhibiZone as well as other antibiotic coatings have been shown to decrease infections for inflatable penile prosthesis procedures; however, adding InhibiZone to the AUS has not shown to have an effect on infections rates. Deep vein thrombosis prophylaxis should be used by AUA guidelines depending on the patient’s risk factors, which can include pneumatic compression devices and subcutaneous heparin.
Patient Positioning and Preparation
The location of the placement of the urethral cuff may vary depending on the etiology of incontinence and concomitant procedures, including penile prosthesis placement or bladder reconstruction procedures. Most commonly, patients undergo bulbar urethral cuff placement, which is performed with the patient in the dorsal lithotomy position for a perineal or transscrotal approach. Care is taken to pad the bony prominences that cause pressure points to avoid skin breakdown. The perineal approach allows for access to the proximal urethra at the level of bifurcation of the corporal bodies, which is the ideal location for treatment of PPI. Patients undergoing placement of the sphincter at the bladder neck (more common in the pediatric population) are placed in the supine position with an abdominal retropubic approach.
After the patient is induced under general anesthesia, the skin is shaved to include the infraumbilical abdomen, genitalia, and perineum. Per instructions from the manufacturer, it is recommended that the patient’s skin be scrubbed with a povidone–iodine soap for 10 minutes before surgical prep. If the patient is allergic to iodine, a chlorhexidine scrub can be performed. Studies show that a preoperative chlorhexidine scrub can reduce the perineal colonization rate up to fourfold. A 14-Fr Foley catheter is placed before incision is made to empty the bladder and avoid urine drainage into the field. The catheter also allows for easier urethral identification and dissection during the procedure. The scrotum can be elevated with towel clips or silk sutures to allow for better visualization per surgeon preference. The anus must be excluded from the field with secure drapes to avoid contamination.
Device Preparation
The AUS has three components: cuff, pump, and reservoir ( Fig. 102.1 ). Each component of the device needs to be prepared. This step can be performed by the surgeon or one of the members of the surgical team depending on surgeon preference. Hemostats need to be prepared by the surgical technician by covering the jaws with silicone tubing to avoid damage to the component tubing by the metal jaws of the hemostat.
The control pump is prepped by placing the both sets of tubing of the pump in a basin of normal saline solution or diluted contrast. The use of contrast as the filling solution is based on surgeon preference. The pump is held at a 45-degree angle with the button on top, and the pump is squeezed and released repeatedly until all of the air in the pump has been displaced with fluid. While still submerged, the tubing is then clamped approximately 4 to 5 cm from the end using the rubber-shod hemostats with one notch only. The pump should then be placed in an empty sterile tray or kidney basin and covered with a sterile drape. Because the pump is impregnated with InhibiZone, it should not be placed in a saline solution, which this will dilute the concentration of antibiotics on the device. It is also recommended to lock and unlock the control pump several times during preparation with the expectation that it will not be as difficult to initially unlock the device at the time of activation.
The pressure-regulating balloon (PRB) is available in multiple pressures: the 61- to 70-cm water cuff as standard and the 51- to 60-cm water cuff used for patients who have undergone radiation. The PRB is prepped by attaching a 15-gauge blunt-tipped needle to a 30-mL syringe filled with 25 mL of filling solution (normal saline or contrast). The air-filled balloon is deflated manually, and the needle is attached to the balloon tubing. The excess air is aspirated from the balloon with the syringe upright. The balloon is filled with 20 mL of filling solution. The balloon is rotated to gather any bubbles together, and the entire contents of the balloon are aspirated into the needle. The tubing is then clamped with a rubber-shod hemostat. The balloon is not impregnated with antibiotics, so it should be submerged into a basin containing filling solution or an antibiotic-based solution until implantation.
The cuff is prepared in a similar fashion as the PRB. A 15-gauge blunt-tipped needle and 30-mL syringe with 10 mL of filling solution are attached to the cuff tubing after it has been manually deflated. The excess air is then aspirated. The cuff is filled with 1 to 5 ml of filling solution depending on the cuff size. An excessive amount of fluid should not be used when removing air bubbles from the cuff to avoid overfilling and loss of optimal effect at the measured cuff size. The air bubbles are collected into one large air bubble, and the entire contents are aspirated. The tubing is clamped with one or two rubber-shod hemostats and then placed on a sterile tray as the cuff is treated with InhibiZone.
Incision
Using the perineal approach, a midline incision is made with a scalpel to incise vertically onto the bulbospongiosus muscle ( Fig. 102.2 ). The tissue surrounding the urethra and spongiosum muscle is preserved if possible by dissecting the muscle off of the urethra laterally using blunt dissection or with Metzenbaum scissors ( Fig. 102.3 ). Care is taken to try to preserve the muscle to reapproximate at the time of closure for an additional layer of tissue to cover the implant. Electrocautery should be used minimally to avoid thermal tissue damage to the urethra. The corporal bodies are identified to aid in dissection around the dorsal urethra. Sharp dissection with Metzenbaum scissors is used at this point because blunt dissection on the thinner dorsal urethra could cause tissue damage. If the urethra is entered, the recommendation is to close the urethra with 4-0 absorbable sutures and abort the procedure. Some surgeons, however, repair the urethra and move the cuff placement site away from the urethral injury with delayed activation. One must weigh the risks and benefits based on the extent of injury and risk of erosion before proceeding with cuff implantation in this instance.
Cuff Placement
After the urethra is dissected circumferentially, a right angle clamp is passed behind the dorsal aspect of the urethra, and a Penrose drain or vessel loop is passed to allow for further dissection. The space is enlarged to accommodate the width of the cuff. Ideally, the dissection is performed proximally to attempt to place the cuff as close to the crura as possible. Care should be taken to avoid excessive dissection because the cuff should not be mobile in the perineum.
The cuff sizer is then passed behind the urethra where the cuff is to be implanted to measure the urethral circumference. If a catheter larger than 14 Fr is used, it should be removed before cuff sizing. The cuff should fit snugly without constricting the urethra. Typically, a 3.5- to 4.5-cm cuff is used in the bulbar urethra, but sizes up to 11 cm are available. If the cuff sizer is not available, a Penrose drain or vessel loop can be used to measure the urethral circumference ( Fig. 102.4 ). After the appropriate sized cuff is chosen and prepared, a right angle clamp should be passed under the urethra from the same size as the pump and PRB. The tab on the cuff should be grasped with the right angle clamp with the mesh backing toward the outside and the pillow side toward the urethra. The tubing is then passed through the hole until the hemostat meets the hole. A second hemostat is placed on the opposite side of the hole, and then the first can be released. The remainder of the tubing is placed through the hole, and the tab is pulled over the tubing adapter on the cuff. The edges of the tab should fit into the slot around the adapter so it does not become dislodged ( Fig. 102.5 ). The cuff is then rotated laterally off the midline.
