Minimally Invasive Therapy for Urinary Incontinence and Pelvic Organ Prolapse (Current Clinical Urology) 2014th

8. The Artificial Urinary Sphincter

Rose Khavari  and Timothy Boone1

(1)

Department of Urology, Houston Methodist Hospital, 6560 Fannin, Suite 2100, Houston, TX 77030, USA

Rose Khavari

Email: tboone2@tmhs.org

Abstract

Since the first implantation of the artificial urinary sphincter in 1973, thousands of men, women, and children have regained urinary continence, thanks to Dr. Brantley Scott. With long-term data now available, the AUS has become widely used with satisfactory outcomes. Multiple large series have confirmed the AUS to be a durable treatment for sphincter deficiency patients even in patients with neurogenic bladder, radiation treatment, bladder neck contracture, failed slings or injectables, mixed urinary incontinence, or low detrusor pressures. More experience is needed to evaluate the AUS in men with incontinence following minimally invasive treatment of prostate cancer with more contemporary technologies such as brachytherapy, proton therapy, or high-intensity focused ultrasound.

History

Surgical techniques to restore or resemble urethral sphincter function date back to 1947 when Foley reported his experience with an external cuff placed around the urethra and manually operated by the patient using a pneumatic piston [1]. Thereafter, Berry in 1961 used an acrylic block underneath the bulbocavernosus muscle to cause permanent compression of the urethra [2] and similarly Kaufman used a silicone-gel prosthesis to compress the bulbar urethra in postprostatectomy patients [3]. Unfortunately, these devices were plagued with high rates of infection, urethral erosion, and poor continence rates. These complications led investigators to balance the pressure placed on the urethra, by trying to keep it less than the body’s systolic blood pressure, while providing sufficient pressure to create continence. Eventually, in 1973, Scott implanted the first-generation artificial urinary sphincter known today as the AMS 800 Artificial Urinary Sphincter (American Medical Systems, Inc., Minnetonka, MN) [4] and since Scott’s time this device has undergone minimal changes to its current AMS 800™ Urinary Control System configuration introduced in 1983. The AUS has proven to be an effective treatment for stress urinary incontinence and is regarded as the “gold standard” by many experts. The contemporary AUS device has many advantages over preceding devices: it functions in a non-obstructive pattern with voiding, the pressure in the system is regulated by the reservoir balloon and not the patient, and it can be used for incontinence in both male and female patients [5].

The AMS 800 AUS has three components: (1) The cuff placed around the bulbar urethra or the bladder neck, (2) the balloon reservoir with various pressures (51–60, 61–70, 71–80 cmH2O), and (3) the scrotal or labial pump that contains the control mechanism and the deactivation button. Since all the three components can easily be connected and the system can be locked in a deactivated state, the AMS 800 AUS can be implanted in a single stage. After the recovery period, the AUS is activated by the pump allowing fluid in the system to fill the cuff and create a continent state. When the patient is ready to void, he or she can squeeze the scrotal or the labial pump and allow the fluid in the cuff to empty and return to the pressure regulating the balloon. After voiding the fluid automatically returns from the balloon to the cuff, repressurizing the system, thus closing the urethra.

Patient Selection, Evaluation, and Preoperative Workup

Although most artificial urinary sphincters are placed in postprostatectomy men with stress urinary incontinence, any male or female patient with stress urinary incontinence can potentially be a candidate for AUS implantation. There is no strict lower limit or higher limit on the amount of incontinence. Females, children, patients with neurogenic bladder, or augmentation cystoplasty can be appropriately evaluated and potentially benefit from AUS. Along with counseling for AUS implantation, a history and physical exam, urodynamic testing, and cystourethroscopy is recommended.

During history taking, the urologist should determine the cause for the patient’s incontinence (neurogenic, trauma, intrinsic sphincter deficiency, radiation, postprostatectomy, postcystectomy, etc.). Previous surgical procedures on the bladder and the urethra should be evaluated as well along with other comorbidities and conditions, including the patients overall health, anticoagulation use, skin conditions, meatal stenosis, urethral strictures, and mixed urinary incontinence (urge and stress). Furthermore, assuring that the patient is able to use his or her hands and has sufficient dexterity is an important part of the preoperative evaluation. The patient’s willingness and cognition to operate the cuff every 4–6 h during the day should also be a part of preoperative discussion and counseling. One may also want to determine which hand is dominant for the patient in order to place the pump on that side of the scrotum or labia to facilitate operating the pump for the patient.

The physical examination should include a thorough genitourinary exam in males (skin infections, hernias, previous hernia surgeries, hydroceles, etc.) and a complete pelvic exam in females since concurrent pelvic organ prolase, or vaginal atrophy may be present. Presence of some of these findings may require repair at the same setting or require staging prior to AUS procedure.

Although the use of preoperative urodynamic testing in postprostatectomy patients undergoing AUS implantation is controversial, it can be used to confirm intrinsic sphincter deficiency, identify bladder capacity (we recommend a minimum of 250 mls), detrusor compliance, and voiding pressures and patterns [6]. Lai et al. in 2011 reported their experience with preoperative overactive bladder symptoms and mixed urinary incontinence in 129 postprostatectomy patients undergoing AUS implantation. They concluded that preoperative overactive bladder symptoms did not adversely impact the patient’s outcome after AUS placement. Furthermore, most of the patients with mixed urinary incontinence will continue to have their overactive symptoms after surgery, making preoperative counseling imperative. Development of de novo overactive symptoms in our series was 23 % [7].

The authors recommend cystourethroscopy in all patients undergoing AUS. This will allow the physician to evaluate the urethra for any strictures, and the bladder for any foreign bodies, tumors, or stones. If any of these are discovered, they should be resolved prior to proceeding with AUS implantation.

Operative Techniques

Preoperatively, patients are counseled appropriately regarding the risks of infection, erosion, bleeding, and need for further procedures. A negative urine culture must be present. The perineum is examined in the preoperative setting to ensure that there are no signs of skin infection or breakdown. Perioperative deep vein thrombosis prophylaxis and perioperative antibiotics are administered based on AUA best practice guidelines [8]. Hair in the perineum is trimmed right before the surgery. If a bulbar urethral cuff is planned, the patient is positioned in lithotomy with appropriate padding. If a bladder neck cuff is anticipated, a frog leg position is suitable. The authors do a full 10 min skin preparation with iodophor-based solution. We also recommend copious irrigation with antibiotic solution throughout the procedure.

The cuff can be placed around the bulbar urethra which is the most common technique used in men, or around the bladder neck through a suprapubic approach in children, or using a vaginal approach in females.

For the bulbar urethral technique, the patient is placed in lithotomy position and we place a 12F Foley to have the bladder drained during the procedure. By palpating the catheter in the perineum, we identify the point of its turn through the pelvic floor and mark that as the middle of our incision. A vertical incision of about 5–6 cm is made and a Scott ring retractor (Lone Star Medical Products, Houston, TX) is used for exposure. Sharp dissection is used to expose the bulbocavernosus muscle which then is divided in the middle and retracted to the sides to expose the bulbous urethra. Using sharp dissection, the bulbar urethra is freed circumferentially. Care is taken to do the dissection distal to the turn of the urethra to avoid injuring the posterior urethra. When the dissection is done safely, a right angled clamp is passed and the circumference of the urethra is measured by a measuring tape. The integrity of the urethra is assured by using a small caliber soft angiocath and injecting the antibiotic solution at the meatus alongside the Foley while gently pulling on the Foley balloon to close the bladder neck. If the urethra distends and there is no leak, we proceed with the measurement and the implantation. At any point, if there is any injury to the urethra, the surgery needs to be stopped and the AUS implantation postponed to a later date. The high risk of erosion and infection in the presence of urethral perforation biases us to stop the elective procedure. Based on our experience, most bulbar urethras will require a 4.5 cm cuff (range 3.5–5 cm). From this point on, the sharp instruments on the field are used with care avoiding contact with the artificial urinary sphincter components.

Prior to implantation of the AUS, all components are irrigated with normal saline and air is aspirated from all components and tubing. This will ensure the hydraulic mechanism of the system runs smoothly and decreases the risk of air interfering with the pump locking mechanism. The cuff is pulled posterior to the urethra using a right angled clamp and wrapped around and secured in place by placing the plastic tab over the button, ensuring the button is seated securely. Then our attention is turned to create a pocket for the pressure balloon in the space of retzius. Since most of our patients are postprostatectomy individuals, the bladder is often adherent to the fascia. Therefore, we make a small suprapubic incision and carry it down to identify the fascia. The fascia is opened with sharp dissection under direct vision and a small pocket is created lateral to the midline incision underneath the rectus abdominus muscle. Usually a 61–70 cmH2O pressure balloon reservoir is chosen which is filled with 22 cc of saline. Although various contrast media and dilutions were used in the past to fill the tubing and the device, we currently use normal saline in almost all cases. Then the rectus abdominus fascia is closed and a tunnel above the fascia, starting from the most caudal portion of the incision to the base of the scrotum, is created. A subdartos pocket in the most dependant part of the scrotum is made using a long clamp. A long nasal speculum is used to guide the pump into the scrotal pocket where it is held gently with a Babcock clamp placed across the tubing and skin above the pump. All the tubing is brought to the suprapubic incision, trimmed to fit without excess tubing, and connected under direct vision using quick-connect system after ensuring the pressure balloon is filled appropriately. After all connections are made, the tubing can be secured to the fascia with one or two interrupted sutures over the connectors to make the tubing less palpable by the patient. We have found that tubing fixation in this manner helps prevent pump migration. The artificial urinary sphincter is cycled under direct vision, and then locked in the deactivated position. The bulbocavernosus muscle is reapproximated and the perineal incision is closed using long-lasting absorbable sutures in multiple layers and approximating the bulbocavernosus muscle.

For bladder neck placement of the AUS cuff, the patient is placed in the frog leg position and a low midline or pfannenstiel incision is made. The bladder is mobilized and the endopelvic fascia is identified and opened under direct vision. The bladder neck is freed up posteriorly for about 2 cm separating it from the rectum in males and the anterior vagina in females. EEA Sizers™ in the vagina or the rectum can help to separate these organs during difficult dissections in previously operated or radiated fields. If identifying the bladder neck is difficult, one can make a small anterior cystotomy in a more cephalad part of the bladder to inspect and identify the bladder neck more precisely as long as this is well away from the cuff. Any small perforation to the bladder or the urethra can be closed primarily and the procedure could be continued to the conclusion as long as the cuff is not placed over the perforation. The authors prefer to postpone the cuff placement unless the cystotomy is anteriorly located and well away from the bladder neck. We also recommend waiting 6 weeks prior to activating the AUS system. On the contrary, if an injury to the rectum occurs, then placement of the AUS should be aborted. The cuff size used during this technique varies between 5 and 11 cm and the pressure balloon most commonly used is 71–80 cmH2O which is placed in the retropubic space. The pump is placed in the labia or the scrotum as discussed previously. All tubing is brought anterior to the rectus fascia and connected securely where the device is cycled under direct vision.

The bladder neck cuff can also be placed through a vaginal incision in females. After placing the patient in lithotomy and placing a Foley catheter, an inverted U incision is made with the apex at the bladder neck. The vaginal flap is completely freed up and the endopelvic fascia is identified bilaterally and perforated. The bladder neck and the proximal urethra is freed up and a measuring tape is used to measure the circumference of the bladder neck. A cuff is placed and we recommend cystoscopy to ensure that the cuff is placed distal to the ureteral orifices. The bladder is tested for any inadvertent cystotomies which are repaired if identified. The rest of the procedure is similar to the one described above.

Postoperative Care

We recommend continuing the intravenous antibiotic for 24 h per AUA best practice guidelines and early ambulation. Strict glucose control in the perioperative period is imperative in diabetic patients. The catheter is removed 24 h postoperatively and we ensure the patients can empty their bladder without any difficulty prior to being discharged. We activate the AUS in 4–6 weeks in the clinic and provide appropriate patient education. Patients are instructed to recognize signs and symptoms of infections in the skin or the urine and immediately notify their physician. In addition they are counseled to notify other health care providers of their implant and they are educated that the AUS needs to be deactivated when a catheter must be inserted in their urethra.

Complications

Urethral Atrophy

The most common cause for revision surgery following AUS placement is urethral atrophy reported at 9.6 % [9]. This is defined as failure of the urethra below the cuff to completely coapt which can be visualized during cystoscopy, along with low Valsalva leak point pressures during urodynamics, loss of visibility of contrast in the cuff on X-ray (in circumstances where contrast is used), and ultimately confirmed by urethral thinning during surgical exploration. Various techniques are used to address this complication which are discussed in a later part of this chapter in more detail.

Infection

Despite all precautions taken, some patients will develop infections which can be abrupt or chronic and may require intravenous antibiotics or explantation of the device. In 1995 Martins and Boyd reported their experience with postoperative infection-erosion patients by isolating a pleomorphic group of organisms, specifically enteric, Gram-positive, and anaerobic organisms by culture [10]. Although, most experts believe Staphylococcus epidermidis is the most common organism, Magera et al. showed that Staphylococcus aureus was the most common organism in their series [11]. Unlike other infections, infections involving AUS can occur without any fever, leukocytosis, fluctuance, or purulence. Patients with an AUS infection usually present with inflammation, erythema, edema, and pain in the perineum or the pump. Having a high index of suspicion will prompt the diagnosis and immediate treatment can be helpful in improving patient outcomes. Usually new onset pain is a sign of AUS infection. In select patients social continence can be restored with reinsertion of the AUS following removal for infection or erosion [12]. Lai et al. reported their experience with 21 secondary reimplant cases following explantation due to erosion or infection. The authors reported a fourfold increased risk of future cuff erosion when compared to virgin cases. However, overall good functional outcome with an acceptable continence rate was achieved in their reoperative series [13].

Device Failure

Most experts would agree that the life of the AUS is usually between 10 and 15 years. However, various mechanical or functional defects can lead to AUS dysfunction. Leak in the device is one of the most common mechanical failures wherein patients complain of recurrent incontinence, a completely flat pump or the feeling of air in the system. In our experience the pressure control pump is the most common site to fail probably due to bending the pump to open the cuff over many years. The silicone-coated cuff, tubing, and the reservoir are less likely to be the source of fluid leak. The leak can be identified in the operating room by using an ohmmeter to identify the leaking component and revise the individual component as needed when the device is only several years old.

Debris, air, or kinks in the tubing can also lead to malfunction. Patients may report that they need to use the pump more often to completely empty their bladder over many years with the AUS. Concurrent changes in bladder function with age must be taken into account as well. These issues can be minimized by meticulous primary surgical techniques and careful evaluation later on, however, revisions may be needed.

Special Circumstances

Artificial Urinary Sphincter in Children

The functional results of implanting the artificial urinary sphincter in children are variable. Cattie et al. in 2008 reported their experience in 44 children (age range 8.6–29.5 years) who had undergone an AUS implantation for severe urinary incontinence secondary to neuropathic bladder dysfunction. They reported frequent complications of urinary retention (24), urethral erosion (2), scrotal erosion (5), and mechanical dysfunction (7). This led to 9 removals, 5 deactivations, 6 revisions, and 5 total replacements [14]. In another study from Ruiz et al., presenting their 14-year experience of AUS implantation in children and adolescents, they reported a 86.3 % survival rate of the implant and a 26.3 % revision rate with overall continence of 87 % [15]. They noted more complications with extrophy patients who had multiple previous procedures on their bladder and bladder neck.

Artificial Urinary Sphincter in Neurogenic Bladder, Spinal Cord Injury, and Neobladder

In most pediatric and adolescent patients who have undergone AUS implantation, a neurogenic cause has been the primary reason for their stress urinary incontinence. The adult literature also supports implantation of AUS in selected patients who have appropriate bladder compliance and capacity with good outcomes and acceptable complications. Kastler in 2011 reported their experience in a multicenter-retrospective study on 51 adult patients where 31 % (16/51) had spina bifida and 69 % (35/51) had spinal cord injury with a 74 % continence rate after 10 years of follow-up [16]. Patients with severe stress urinary incontinence who have undergone cystoprostatectomy with a continent ileal neobladder can regain continence by implanting an artificial urinary sphincter. O’Connor et al. reported their experience with five patients who showed a decrease in pad use from 6.2 to 0.6 per day making them completely continent or socially continent [17]. Westney et al. also reported their experience in nine postcystectomy patients with a continent ileal neobladder where the average pad use decreased from 6 to 1 per day (p < 0.005) with two explantations, suggesting the AUS can improve quality of life with comparable complication rates to other series in selected patients [18].

Controversies

Recurrent Urinary Incontinence (Urethral Atrophy)

Recurrent incontinence can be due to multiple factors including device malfunction, erosion, detrusor over activity, and urethral atrophy. Recurrent incontinence secondary to urethral atrophy can be managed by downsizing or repositioning the cuff, placement of an additional tandem cuff, or placement of a male sling [1921]. Each approach, while effective in selected patients, can also have complications such as postoperative infection, erosion, or need for further procedures.

Some degree of urethral atrophy is expected with AUS placement. Normally the pressure-regulating balloon chosen is the 61–70 cmH2O for bulbar urethral cuffs, reserving the 71–80 cmH2O pressure balloons for bladder neck cuffs. In urethral atrophy patients, over time more fluid is needed in the cuff to maintain the desired inflation and coaptation. In general, the volume of urethral tissue under the cuff contributes to effective luminal coaptation. Eventually, the pressure in the balloon would not be able to provide sufficient pressure to provide coaptation for continence and therefore recurrent incontinence occurs. The patient may notice that gradually more pumps are needed to deflate the cuff. The cuff placed at the bulbar urethra and the bladder neck is usually filled with 0.75 cc and 2 cc, respectively. In the setting of urethral atrophy there is usually more fluid in the cuff and the patient may need to pump more to deflate the cuff.

Down-Sizing, Transcorporal Placement, or Repositioning the Urethral Cuff

In 1995, Stone et al. reported a small series of patients with urethral atrophy treated by proximally repositioned cuffs with an 83 % success rate [22]. The authors believed that this approach may have less risk of erosion.

More recently in 2003, Stone et al. followed a slightly larger group of patients for 7 years after downsizing their bulbar urethral cuffs from a 4.5 to 4 cm using the existing space and pseudocapsule. Their patient satisfaction and continence scores improved suggesting this approach is an effective and safe method to manage urinary incontinence secondary to cuff-induced urethral atrophy [19]. Minimal dissection is needed during this approach and the other components of the device are not manipulated, thus decreasing the risk of infection and the time to reactivate the AUS.

Some experts argue that during AUS revisions the urethra is vulnerable to injury and most commonly the cuff is placed in a more distal location inadvertently requiring a much smaller size. Therefore, transcorporal placement of the cuff has become popular among some implanters with the belief that this will allow for more bulk around the urethra and more appropriate cuff sizing with less risk of erosion. In 2002, Webster et al. reported their experience in 31 patients, with a mean follow-up of 17 months, in patients who underwent AUS revision using a transcorporal cuff showing that 84 % of the patients had occasional stress urinary incontinence [23]. This technique can only be an option in the patient with preexisting erectile dysfunction since entry of the corpora will damage tumescence.

Insertion of a Tandem Cuff

Originally, Brito et al. in 1993 described placement of tandem bulbar urethral cuffs in patients with severe urinary incontinence who still suffered from persistent leakage following AUS placement. They increased their continence rate from 85 to 95 % [9]. In another series with longer follow-up of 74.1 and 58.0 months for single and double cuff patients, respectively, O’Connor et al. reported no significant improvement with a double cuff placement. However, the patients with double cuff insertion had a higher complication rate and required further interventions [9].

Placing a tandem cuff as a salvage procedure for recurrent stress urinary incontinence with longer follow-up (mean of 3.3 years) was reported by Elliott et al. in 2003. The authors reported improved continence and patient satisfaction in their series. Their reoperation rate due to leakage and erosion was 1 and 2 % in 18 patients, respectively [24].

Furthermore, in a selective group of patients with a high risk of infection and erosion, salvage transcorporal tandem cuff placement has been proposed. In 2007 Elliott et al. reported a small number of patients who had undergone tandem transcorporal cuff placement suggesting yet another effective alternative for approaching this complicated group of patients [20].

Male Sling after Urethral Atrophy Following Artificial Urinary Sphincter

More recently several investigators have proposed the use of a non-bone-anchored transobturator suburethral sling such as the AdVance Sling (American Medical Systems, Minnetonka, MN) to manage recurrent urinary incontinence secondary to urethral cuff-induced atrophy. This approach may decrease entry to the capsule formed by the urethral cuff, therefore less risk of infection. In addition the downtime of AUS activation after a second AUS cuff placement or a revision is eliminated with this technique. Non-bone-anchored transobturator male slings work by elevating the urethra rather than compression. Christine et al. have suggested that in selected patients in whom the external sphincter is still partially functional by external compression during cystoscopy may experience improvement in their recurrent incontinence with salvage AdVance Sling. Furthermore, in their small retrospective report, the authors showed that in over 50 % of their patients continence was obtained without reactivation of the AUS [21].

Artificial Urinary Sphincter Following a Failed Male Sling

The literature does not have sufficient data regarding implantation of AUS following a failed non-bone-anchored transobturator male sling. Most likely this can be explained by the fact that these slings are recent to the field and a long-term follow-up is still pending. However, Fisher et al. reported their experience with 11 patients having failed a bone-anchored male sling who subsequently underwent an artificial urinary sphincter placement. In their small series, with a mean follow-up of 14.2 months, they reported feasibility of this procedure with high patient satisfaction and no intraoperative complications or urethral injuries. However, one AUS had to be explanted due to infection [25].

Nocturnal Deactivation

There is some controversy among experts regarding nocturnal deactivation of the AUS which may provide a ”rest period” and decrease the incidence of urethral atrophy. In 2001, Boone et al. reported a retrospective comparison, with a long term follow-up, comparing patients at Mayo Clinic who deactivate their AUS at night compared to Baylor patients who keep their AUS activated at all times except during voids. It appears that the risk of urethral atrophy and recurrent incontinence was less in nocturnal deactivation group (10 % vs. 21 %). Therefore, the authors suggest nocturnal deactivation for motivated patients who are dry at night and would like to decrease the risk of urethral atrophy [26].

External Bulking Agents

In cases of severe urethral cuff atrophy, when the maximal circumference of the urethra is less than 4 cm, some experts have tried using external bulking agents. Lue et al. in 2005 reported their experience with wrapping an external urethral bulking material (Surgisis ES, Cook Urological, Spencer, IN) in patients with a small urethra in order to enhance the diameter of the urethra prior to placing a 4 cm cuff. In their series of five patients they reported this technique to be feasible and well-tolerated with satisfactory results [27].

Radiation and AUS

External Radiation Therapy

Only a few studies pertaining to radiation in patients with postprostatectomy incontinence requiring an AUS focus on preoperative evaluation, complications, success, and other specific considerations. Radiation is known to affect the urethra, bladder, and the surrounding tissues making the area more susceptible to infection and erosion secondary to tissue hypo-vascularity [28]. In addition, the bladder exposed to radiation may become smaller in capacity and experience more overactivity. Hemorrhagic cystitis, another potential complication following radiation therapy, can be a challenge for radiated patients who are being evaluated for AUS placement. In 1995, Boyd et al. reported their outcomes of AUS placement in patients undergoing major pelvic surgery with or without radiotherapy. Thirty four out of their eighty one patients had received radiation either in an adjuvant setting or as a primary treatment. They recommended waiting 12 weeks prior to activating the AUS and had acceptable overall results [28]. In another small series a social continence rate of 87 % with an overall complication rate of 25 %, and erosion/infection rate of 12.5 % was reported [29]. In one review, with a mean follow-up of 31 and 36 months in two groups of postprostatectomy patients who did not and did receive radiation, respectively, Boone et al. reviewed their results of continence, urodynamic testing, complication rate, overall satisfaction, and quality of life. Their radiation group included patients who had external beam radiation as their primary treatment with or without salvage prostatectomy, or radiation given in an adjuvant setting. They reported similar continence rates, urgency with or without urge incontinence, and satisfaction rates in both patient groups. They also report that their rate of infection, erosion (14 %), and reoperations were similar in these two groups [30]. Based on their findings, the authors recommend that no special precautions or consideration is necessary in patients who have received radiation compared to the patients who have not. These reasonable results with AUS placement in patients with prior radiation history may argue that the bulbar urethra is outside of the radiated field. In addition, current external beam radiation is much more precise and with a smaller treatment target, the affected field is much more limited.

In our experience, and by consulting the literature, AUS implantation following radiation therapy alone is rare. Most data available and experiences mentioned above apply to patients with adjuvant or salvage radiation therapy. Our unpublished experience shows radiotherapy after implantation to be well tolerated in the setting of biochemical recurrent disease.

Another topic of concern and discussion is the functional bladder change that occurs in patients who have undergone radiation. Prior radiation may promote bladder fibrosis and instability. In the study reported by Hadley et al., radiated patients had more bladder instability, smaller bladder capacity (less than 300 ml), low compliance (less than 20 ml/cm water), and early bladder sensation (at a volume less than 85 ml) but the difference was statistically significant only for bladder instability (p < 0.05) [29].

Minimally Invasive Therapy for Localized Prostate Cancer Treatment

Traditionally, the treatment choices for prostate cancer had been prostatectomy or radiation therapy. Recent sophisticated technology has introduced alternative methods in managing localized prostate cancer. These include proton beam therapy, cryoablation of the prostate, brachytherapy, and high-intensity focused ultrasound (HIFU). Although some promising results have been suggested by these techniques with a short-term follow-up, their complication rates, including urinary incontinence of 4–40 % is variable and concerning [31].

Data regarding artificial urinary sphincter implantation following these techniques is very limited in the literature. Benoit et al. reported placement of AUS in 4 men out of 2,124 men in Medicare population that had undergone brachytherapy [32]. Instrumentation across the AUS for recurrent prostate obstruction or chronic sloughing of necrotic tissue can be very difficult.

Recurrent Bladder Neck Contracture and AUS

Obstruction of the outlet in postprostatectomy or cystectomy patients due to bladder neck contracture can be managed by transurethral electrocautery resection, laser ablation, or direct visual internal urethrotomy. If the patient responds to this management and establishes an open bladder neck, a subsequent artificial urinary sphincter can be inserted. However, in many cases the bladder neck contracture is recurrent and does not respond to endoscopic management and the insertion of a urethral wall stent becomes an option. Use of a urethral stent is reserved for very selected cases. Elliott et al. also reported their experience with successful placement of AUS following Urolume™ placement with minimal morbidity and 89 % patient satisfaction after 17.5 months of follow-up [33]. Magera et al. report a median of three failed endoscopic management of recurrent bladder neck contracture in their series. They were able to stabilize the bladder neck in 13 out of 25 patients with one stent and in 6 out of 25 patients with 2–4 stents. Urinary continence was then achieved by placement of artificial urinary sphincter with satisfactory results [34]. Lai et al. also showed that a staged UroLume™ stent with delayed artificial urinary sphincter implantation provided good continence control in 8 out of 11 patients with recurrent bladder neck contractures [35]. In conclusion the authors believe that in highly selected patients the bladder neck contracture can be stabilized with UroLume™ stent followed by implantation of artificial urinary sphincter. Early studies using Mitomycin C as an adjuvant to internal urethrotomy may provide another tool in managing the recurrent bladder neck contracture prior to AUS placement [36].

Conclusion

Since the first implantation of the artificial urinary sphincter in 1973, thousands of men, women, and children have regained urinary continence, thanks to Dr. Brantley Scott. With long-term data now available, the AUS has become widely used with satisfactory outcomes. Multiple large series have confirmed the AUS to be a durable treatment for sphincter deficiency patients even in patients with neurogenic bladder, radiation treatment, bladder neck contracture, failed slings or injectables, mixed urinary incontinence, or low detrusor pressures [3537]. More experience is needed to evaluate the AUS in men with incontinence following minimally invasive treatment of prostate cancer with more contemporary technologies such as brachytherapy, proton therapy, or HIFU.

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