Artificial Urinary Sphincter Implantation Using a Bulbous Urethral Cuff: Perioperative Care.
The first artificial urinary sphincter was implanted in 1972. Since then, many advances in product design, improvements of surgical techniques, and proper patient selection have resulted in decreasing complication rates and improved patient satisfaction (Light, 1993). The currently used artificial genitourinary sphincter (AGUS) is the American Medical Systems (AMS) 800. This prosthesis consists of silicone components: (a) an elastic pressure-balloon reservoir, (b) a control pump, and (c) an inflatable occlusive urethral cuff. The balloon reservoir holds a volume of fluid which exerts a range of preset pressures (51-60, 61-70, 71-80, and 81-90 cm water) that can be selected for the site of cuff placement and the clinical situation. The pump contains a unidirectional valve, a refill-delay resistor, and a deactivation button. This assembly allows for complete control of cuff activation/deactivation by the patient. In the activated mode, the urethral cuff is depressurized (deactivated) by squeezing the pump, ther eby forcing fluid from the cuff through the unidirectional valve into the balloon reservoir (see Figure 1). Following a delay of 3 to 5 minutes, fluid automatically flows back to repressurize the cuff, thus allowing enough time for the patient to void.
The AMS-800 can be non-surgically deactivated for prolonged periods of time by pressing the deactivation button on the pump, which prevents fluid in the balloon from returning to the cuff. Deactivation allows for healing to take place without compressing the urethra. Deactivation also facilitates catheterization, cystoscopy, and transurethral resection, if necessary. Activation is accomplished by a sustained squeeze of the pump. Given the mechanical nature of the AGUS, patients must be informed of the possibility of mechanical failure and the potential need for surgical repair, revision, or removal due to erosion, infection, or rejection (Elliott & Barrett, 1998).
Indications for AGUS Implantation and Patient
The candidate for AGUS implantation is the patient with urinary incontinence due to sphincteric insufficiency, with normal detrusor function and bladder compliance. Recognizing that urinary incontinence may be the result of co-existing sphincteric incompetence and bladder compliance and contractility abnormalities, AGUS implantation can be considered in these patients assuming that these coexisting abnormalities can be adequately managed.
Patients with sphincteric incontinence from a variety of causes are appropriate candidates for AGUS implantation. In our experience, the most common etiologies for incontinence requiring AGUS are following radical retropubic prostatectomy and transurethral resection of the prostate (Elliott & Barrett, 1998). A minimum of 6 months is recommended between the time of prostatectomy and AGUS implantation to allow time for continence to return. Sphincteric insufficiency may also develop following injury or radiation to the pelvis and spinal cord. Congenital disorders such as myelomeningocele can also result in loss of sphincteric function. The bladder neck is the site of cuff placement in these patients. All women and children who are candidates for AGUS implantation have cuffs placed around the bladder neck. The bladder neck is the optimal location for AGUS implantation because of the thick muscular tissue and good blood supply in this area. However, following prostatectomy, the bladder neck tissue becomes scarred and fixed to the surrounding tissues, and, therefore, the bulbous urethra is the preferred site for cuff placement in this group of patients.
Preoperative evaluation should include urine analysis, urine gram stain and culture to assure that the urine is sterile prior to AGUS implantation. Upper tract abnormalities should be evaluated with excretory urogram and/or voiding cysto-urethrogram if warranted by the patient's history. Surgical repair of grade two, or greater, reflux should be done at or before the time of AGUS implantation. Bladder augmentation may be required in patients with noncompliant, low-capacity bladders to make them suitable candidates for AGUS implantation. Urodynamic studies and cysto-urethroscopy are necessary to carefully evaluate voiding dysfunction and exclude anatomic abnormalities.
Compliance is a major consideration for a successful outcome. A preoperative demonstration of the AGUS is provided along with an explanation of the perioperative experience and postoperative instructions.
Infection precautions cannot be overemphasized when preparing patients for surgery. Patients are admitted on the morning of surgery. Broad-spectrum intravenous antibiotics, most commonly vancomycin and gentamicin, are administered in the preoperative holding area. Antibiotic prophylaxis must include coverage for Staphylococcus epidermidis and Escherichia coli, as these organism are responsible up to 80% of genitourinary prosthetic infections (Blum, 1989). Hair on the lower abdomen, genitals, and perineum is removed just prior to surgery to prevent bacterial colonization (Elliott & Barrett, 1998).
In the operating room, strict adherence to sterile techniques are essential to minimize potential infections. A complete 10-minute surgical scrub (abdomen, external genitalia, and perineum) with iodophors is undertaken immediately following the surgical shaving. Draping should allow access to the lower abdomen and perineum. A silicone 12-French Foley catheter is inserted in all patients after preparation and draping. All operating room personnel should wear surgical hoods to limit contamination of the operative field, and traffic in and out of the operating room should be limited (Elliott & Barrett, 1998). The prosthesis should be handled only when necessary and should be isolated away from tissue, blood, and sponge and towel fibers, which could cause malfunction of the device (see Figure 2).
The patient is positioned in the dorsolithotomy position to expose the perineum. A 4 to 5 cm midline skin incision is made over the bulbous urethra (see Figure 3). Through the perineal incision, deeper tissues are divided and carried down until the bulbocavernosus muscle is identified. With a hand-held Young retractor exposing the bulbous urethra superiorly and the Gelpi self-retaining retractor providing lateral exposure, sharp dissection is carried out around the bulbocavernosus muscle. A plane is established between the bulbocavernosus muscle and the tunica albuginea of the corporal bodies circumferentially for a length of 1.5 to 2 cm. This plane allows placement of the cuff around the muscular tissue, and not directly in contact with the urethral bulb, to reduce the risk of cuff erosion.
Special care must be taken to avoid injury to the urethra at the 12 o'clock position where the dorsal urethra is attached to the intercorporal septum. In this area, the urethral tissue is thin and dissection can be difficult. A suspected urethral injury can be evaluated by removing the urethral catheter and injecting antibiotic solution or methylene blue solution down the urethra using a bulb syringe. Urethral injury is confirmed if there is fluid leakage into the operative field. An unrecognized urethral injury can lead to early cuff erosion. If the urethra is injured, the defect can be closed with 4-0 or 5-0 absorbable suture and a different urethral segment is chosen for cuff placement. If the urethral defect is large and/or the repair is questionable, the procedure should be abandoned and a Foley catheter left in place.
Although cuffs of varying sizes are available, 267 of 272 (98%) of our most recent patients received a 4.5 cm cuff around the bulbous urethra (Elliott & Barrett, 1998). The cuff is passed tab-first behind the urethra (see Figure 4) in the direction that points toward the side of the subsequent pump and reservoir placement, usually the side of hand dominance. Next, the cuff tubing is brought anteriorly and is passed through the opening in the tab, and the cuff is snapped into place using gentle opposing traction applied to the tab and tubing. The tubing now should be pointed toward the side where the reservoir will be inserted (see Figure 5). A rubber shod clamp closed to the first click is placed near the end of the tubing.
Reservoir placement (see Figure 6) follows by making a 4 to 5 cm transverse incision in the lower abdomen overlying the rectus sheath. The anterior rectus sheath is exposed and subsequently incised parallel to the fascia approximately 2 cm. A pocket is bluntly created to allow placement of the deflated balloon reservoir beneath the rectus muscle in a preperitoneal location. The reservoir tubing is brought through the anterior rectus fascia using a separate stab incision. The balloon reservoir is filled with 22 cc of iso-osmotic contrast medium and a shod clamp is placed near the end of the reservoir tubing, on the first click, to prevent fluid loss. In most patients (82%), a 61 to 70 cm water pressure balloon reservoir is used (Elliott & Barrett, 1998). However, a lower-pressure reservoir, usually a 51 to 60 cm water pressure, is selected to minimize tissue ischemia in high-risk patients such as those who have had radiation therapy or prior surgery. The fascial defect is closed with running absorbable suture after the inflated reservoir is properly positioned deep to the rectus muscle. On the ipsilateral side of the reservoir, a long clamp is passed over the pubis in the plane between Scarpa's fascia and the rectus fascia down to the perineal incision. The cuff tubing is gently grasped and guided up to the lower abdominal wound (see Figure 7).
To facilitate pump placement, an ipsilateral subcutaneous pouch is created superficial to Scarpa's fascia using Hegar dilators up to #15. The pouch extends down to the most dependent portion of the hemiscrotum. The pump is placed in the pouch with the deactivation button oriented laterally so that it is palpable against the skin. To prevent proximal migration of the pump during tubing connection, a Babcock clamp is placed loosely around the pump and scrotal skin.
The appropriate tubing connections are now made. The cuff tubing is connected to the pump tubing with a right-angle connector to prevent kinking, and the reservoir tubing is connected to the pump tubing with a straight connector. Color-coded tubing has simplified this step. Tubing connections are either fastened with 2-0 prolene suture, or with the Quick-Connect set depending on the surgeon's preference. After the connections are completed, all clamps are removed from the tubing and the system is allowed to pressurize. Appropriate cycling of the device is demonstrated and then the sphincter is deactivated so that there is no urethral compression. Drains are not necessary. The abdominal and perineal incisions are closed in layers with absorbable suture and then covered with sterile dressings.
Hospital stay after AGUS implantation using a bulbous urethral cuff is usually 1 day with the occasional patient remaining in the hospital for 2 days. Oral analgesics are usually sufficient for managing pain. Ice packs applied to the scrotum for 24 to 48 hours postoperatively reduce swelling around the pump. Broad-spectrum intravenous antibiotics are continued throughout the hospitalization.
Dressings and the Foley catheter are removed the morning after surgery. Most patients will be able to urinate. If patients are unable to void, intermittent self-catheterization is begun with a small caliber urethral catheter until spontaneous voiding returns. Prolonged catheterization after AGUS implantation should be discouraged due to increased risk of cuff erosion. Some patients will report a transient improvement in urinary control in the immediate postoperative period due to increased resistance from edema near the cuff site. Incontinence is expected during the deactivation period; therefore, some form of protection should be worn until sphincter activation.
Patients should be instructed to gently pull down their pump once each day to prevent upward migration during the capsule-forming period. Oral antibiotics (usually a cephalosporin) are continued for 7 to 10 days following discharge. Patients may shower daily and take a bath 5 days after surgery. Ambulation is encouraged postoperatively. Patients are cautioned to avoid excessive compression of the perineum and lower abdomen. Stool softeners may be prescribed to prevent constipation and straining during a bowel movement. Heavy lifting (greater than 10 pounds) and straining is restricted for at least 6 weeks. Patients with bulbourethral cuffs are permanently restricted from riding a bicycle and horseback riding. Sexual activity should be avoided until sphincter activation. Patients should wear a Medic Alert bracelet to notify medical personnel of the presence of the AGUS and the necessity for cuff deactivation prior to catheterization.
Cuff activation takes place 6 to 8 weeks following implantation. By this time, scrotal swelling and tenderness have subsided, and incisions are well healed. Activation is performed in the office by firm, sustained compression of the pump, allowing the deactivation pin to "pop" into the activated position. Fluid will then enter and fill the cuff. Successful activation and cuff filling can be confirmed with pre and postactivation radiographs. Patients are given another demonstration of how to cycle the sphincter, and are required to demonstrate, independently, how to compress the pump, open the cuff, and void.
Patients who were dry at night prior to sphincter implantation do not require cuff activation for continence while sleeping. These patients should be instructed in cuff deactivation at night. Deactivation has the benefit of reducing the risk of tissue ischemia, urethral atrophy, and urethral cuff erosion. If patients are unable to empty their bladder, they are instructed to practice self-intermittent catheterization (SIC) with the cuff deflated during catheterization.
Persistent or recurrent urinary incontinence is most commonly due to mechanical failure, tissue atrophy, or cuff erosion. Inflate-deflate radiographs can evaluate the hydraulic function of the AGUS. If the radiopaque fluid is not in the system, then a leak has developed. Surgical exploration and close inspection is required to identify the site of leakage. The most common site of leakage is the lower surface of the cuff (Elliott & Barrett, 1998). Once the site of leakage is identified, the individual components can be replaced. If there is fluid present and there is no filling of the cuff during cycling, there is obstruction to flow such as occurs with a tubing kink or foreign body plugging the tubing. Again, surgical exploration is required to identify the location of obstruction. If normal cuff deflation and inflation are present, a urethrogram followed by urethroscopy will exclude cuff erosion. If the onset of the incontinence is insidious, one should suspect cuff-compression tissue atrophy. Urodynamic ev aluation with leak-point pressure measurement and cystoscopy will reveal poor urethral occlusion when tissue atrophy is present. One of three methods can be used to treat recurrent incontinence due to tissue atrophy: (a) increase the pressure of the balloon reservoir, (b) reduce cuff size by 0.5 cm increments, and (c) place a tandem cuff distal to the original cuff in patients with a bulbourethral cuff.
Urinary retention may occur in the immediate postoperative period due to urethral edema. The sphincter should be checked to confirm that it is in the open position. Most patients will begin voiding after a brief period of intermittent catheterization with a small caliber (10-12 French) catheter. If prolonged SIC is required, the cuff should be in the deflated position prior to catheterization. Urinary retention after cuff activation should signal the possibility of stricture disease or bladder neck contracture. Urethral instrumentation should always be performed with the cuff deactivated. If prolonged bladder drainage is necessary, a suprapubic tube should be inserted to avoid urethral cuff erosion. Cuff erosion infrequently presents as urinary retention.
Cuff erosion is a serious complication requiring cuff removal. Cuff erosion can present with pain, swelling, recurrent incontinence, infection, and bloody urethral discharge. Erosion that presents in the immediate postoperative period is due to an unrecognized iatrogenic urethral injury. Cysto-urethroscopy confirms the clinical suspicion. In the absence of infection, the cuff is removed and a stainless steel plug is placed in the cuff tubing. After adequate healing, a new cuff can be inserted. If infection is present, the entire device must be removed. After erosion is identified and the cuff is removed, a silicone catheter should be left in place for 3 to 6 weeks to allow for urethral healing. Prosthetic infections can present at anytime but usually will occur within the first 1 to 2 postoperative months. Infections can present with pain, swelling, fever, induration, skin erosion, or abscess formation. The overall infection rate for primary AGUS implants is 1% to 3% (Carson, 1989). The infection rate increas es in patients following re-operation. Infections in the immediate postoperative period are likely due to contamination at the time of implantation. Treating the infection requires removing the prosthesis. As with any prosthetic implantation, patients should take prophylactic antibiotics prior to dental or surgical procedures to avoid hematogenous seeding.
Mechanical malfunction of the AMS-800 is uncommon, but potential problems include system fluid leak, kinked tubing, and pump malfunction. All the mechanical failures require repair via general anesthesia and AGUS exploration and revision of the failed component.
Hematoma is the most common minor complication of AGUS implantation. Scrotal hematomas can displace the pump and make external manipulation difficult. Most hematomas will resolve spontaneously. Rarely, a large hematoma will require evacuation.
The perioperative care of the patient undergoing AGUS implantation using a bulbous urethral cuff has been discussed. The AGUS has been used to promote urinary continence in patients following radical retropubic prostatectomy or transurethral resection of the prostate when the patient was unable to achieve urinary continence 6 months after surgery. Usually, when continence is achieved, quality of life for the patient is also improved.
Editor's Note: Readers are invited to submit additional manuscripts on this topic, such as nursing care plans, clinical pathways, teaching instructions, or other interventions related to care, followup, and possible complications in patients with artificial urinary sphincters.
Daniel S. Elliott, MD, is Chief Resident, Department of Urology, Mayo Clinic, Rochester, MN.
David M. Barrett, MD, is Professor and Chair, Department of Urology, Mayo Clinic Rochester, MN.
Blum, M.D. (1989). Infections of genitourinary prostheses. Infectious Disease Clinics of North America, 3, 259-274.
Carson, C.C. III. (1989). Infections in genitourinary prostheses. Urologic Clinics of North America, 16, 139-147.
Elliott, D.S., & Barrett, D.M. (1998). The Mayo Clinic long term analysis of the functional durability of the AMS 800 Artificial Urinary Sphincter: A review of 323 cases. Journal of Urology, 159(4), 1206-1208.
Light, J.K. (1993]. Implantation of the AS 800 Artificial Urinary Sphincter. Problems in Urology, 7(3), 402-412.
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|Author:||Elliott, Daniel S.; Barrett, David M.|
|Date:||Apr 1, 2000|
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