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The male sling for postprostatectomy SUI

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					The male sling for postprostatectomy SUI: Indications, technique, and outcomes
The bone-anchored perineal sling has established itself as a safe, efficacious treatment for intrinsic sphincter deficiency in men, especially in those with mild or moderate stress urinary incontinence following prostatectomy. The authors describe the implantation technique and discuss their results with this less invasive alternative to the artificial urinary sphincter.

Despite advances in prostate cancer therapy, the morbidity of each therapeutic intervention remains problematic. With regard to surgical therapies, urinary incontinence continues to be a significant complication.1 However, with refinements in surgical techniques, fewer patients present with severe grades of urinary incontinence; rather, more mild to moderate degrees of leakage are seen in clinical practice. (See the Editorial Board Comment, page 6, before the references.) To this end, interest in less invasive solutions to postprostatectomy incontinence (PPI) has grown. For more than 30 years, the artificial urinary sphincter (AMS 800 Urinary Control System, AMS, Minnetonka, Minn) has been viewed as the most reliable treatment for patients with incontinence due to sphincteric incompetence following prostatectomy and, as such, it has become the gold standard. Over the past decade, however, the male suburethral sling has undergone significant modification and has established itself as a less invasive yet efficacious alternative to the artificial urinary sphincter for the treatment of bothersome stress urinary incontinence (SUI) following prostatectomy. PREVALENCE OF PPI Many types of prostatic interventions can result in urinary incontinence. Specifically, the risk of incontinence following surgery for benign prostatic hypertrophy is approximately 2%,2 but that risk is substantially higher following surgery for prostate cancer. While reports of PPI range from 0% to 80% (depending on the definition of incontinence and the method of evaluation used), approximately 5% to 11% of patients will have sufficient leakage after radical prostatectomy to seek further treatment.1,3 In a patient-derived questionnaire-based study by Stanford and colleagues, only 32% of patients claimed total urinary control, while 7% had frequent leakage, and 2% had no control at 2 years postoperatively.1 Thus, a large disparity exists between physician-derived continence rates and patient-driven questionnaire-based studies. Regardless of the definition of PPI, a significant minority of patients will have enough urinary leakage to require pad usage. While some use the term "social continence" to describe patients who require 1 pad per day for incontinence, a recent study demonstrated that even that amount of use significantly eroded quality of life compared with no pad use.4 Thus "social continence" may not be a satisfactory outcome for many patients, and this understanding forms the basis for treating men with mild to moderate or "social" incontinence. PREOPERATIVE EVALUATION The history, physical, and urodynamics evaluation are the key components of the preoperative evaluation of male SUI. History and physical. A standard evaluation for any man with urinary incontinence begins with a detailed history regarding lower urinary tract symptoms and a physical examination focusing on the neurourologic

assessment. It is important to determine the nature of the incontinence (urge versus stress), degree of bother, number of pads used, circumstances surrounding the development of incontinence (after radical prostatectomy), and length of time since the patient's operation. Also inquire about any prior treatments, particularly at the prostate or outlet level, such as transurethral resection of the prostate or treatment of bladder neck contractures, and current prostate cancer status, including PSA level, need for hormone therapy, and/or use of external radiation therapy (XRT). Urodynamics evaluation. Because the pathophysiology of PPI is variable, the history and physical alone are often unreliable for distinguishing between bladder dysfunction due to poor compliance or detrusor overactivity (DO) and outlet dysfunction due to intrinsic sphincter deficiency (ISD) or bladder outlet obstruction (BOO). Consequently, a thorough urodynamics evaluation is indicated before invasive therapy is recommended. While the majority of men with PPI have a component of sphincteric incompetence,5 only 25% to 50% will have sphincter weakness alone on urodynamics.6 Approximately 40% of patients with ISD have DO or diminished vesical compliance (or both), while up to 15% of patients with PPI demonstrate only bladder dysfunction.6 The most common method for evaluating the integrity of the intrinsic sphincter in PPI is measurement of abdominal leak point pressure (ALPP).7 However, there is no standardized technique for measuring ALPP. Further, catheter size affects measurement of ALPP because scarring at the vesicourethral anastomosis and the resultant diminished urethral compliance can contribute to catheter-mediated obstruction.5 We believe that ALPP is best measured via a rectal catheter. It has been demonstrated that measurement of retrograde leak point pressure (RLPP) via either perfusion sphincterometry8 or measurement of maximum urethral closure pressure via urethral pressure profilometry represents a reliable alternative to ALPP measurement for the evaluation of sphincteric competence following radical prostatectomy.9 It is important to accurately quantify the degree of sphincteric incompetence present, as this may directly alter the treatment recommendation. For example, patients with a higher ALPP (lower degree of ISD) tend to respond better to periurethral bulking agents than do patients with a lower ALPP.10 Conversely, patients with more profound sphincteric incompetence are more appropriately treated with an artificial urinary sphincter or sling surgery than injectables as these agents do not appear to be cost-effective in this situation. WHEN TO CONSIDER SURGERY Treatment within the first year following prostate surgery is usually nonoperative, as many patients will regain satisfactory continence. While pelvic floor exercise training prior to radical prostatectomy aids in the earlier achievement of urinary continence,11 the value of conservative management for PPI generally remains unclear. Regardless, patients are often offered a trial of fluid restriction, pharmacotherapy, pelvic floor rehabilitation, and inhibition techniques. When conservative management fails, surgical intervention is indicated. Options for surgery include transurethral injection of bulking agents, the artificial urinary sphincter, and the male suburethral sling. Contraindications to outlet surgery include:
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untreated low-volume urge incontinence due to DO, disorders that may jeopardize the upper urinary tracts (diminished vesical compliance or detrusorsphincter dyssynergia), and abnormalities that may require future transurethral management (recurrent transitional cell

carcinoma or stricture disease affecting the bladder neck, vesicourethral anastamosis, or urethra). PERIURETHRAL BULKING AGENTS These agents represent a minimally invasive treatment for PPI. Carbon-coated zirconium beads in beta glucan gel (Durasphere, Boston Scientific, Natick, Mass) and bovine glutaraldehyde cross-linked collagen (Contigen, Bard, Covington, Ga) are the most popular injectable agents for SUI due to ISD in men. Reported cure rates for transurethral retrograde collagen injection for post-RRP SUI range from 5% to 20%.10,12 Bugel and colleagues reported a 1-month success rate of 40% for polydimethylsiloxane PDMS (Macroplastique, Uroplasty, Minneapolis, Minn) in men with PPI due to ISD, but that rate dropped to 26% at 12 months.13 ARTIFICIAL SPHINCTER For the past 3 decades, the artificial urinary sphincter has proven to be the most effective long-term solution for male SUI due to ISD, with success rates ranging from 75% to 90% in most modern series and reported patient satisfaction rates of 85% to 95%, despite revisions.14-16 Due to the circumferential compression of the urethra, the corpus spongiosum invariably atrophies, and revision rates when the narrow-back cuff is used range from 17% at 5 years17 to 65% to 80% at 10 years.18,19 The infection rate with initial artificial urinary sphincter surgery is generally low, ranging from 1% to 3%, but infection rates up to 10% have been reported in patients who have undergone XRT or reoperation.15,20 In most recent reports, rates of erosion range from approximately 1% to 5%.15,17,20 The risk of erosion can be minimized by a 6-week deactivation period; during this time, however, the patient remains incontinent. Another drawback to the artificial urinary sphincter is that it requires a certain degree of manual dexterity to manipulate the scrotal pump to void, and many patients find it cumbersome. Further, in our experience, many patients with mild to moderate degrees of incontinence rule out the artificial urinary sphincter since they view it as a more invasive therapy than necessary for the degree of incontinence they are experiencing. SLING SURGERY The modern male sling is based on surgical concepts described by Berry in the 1960s and Kaufman in the early 1970s.21,22 Kaufman described 3 versions of suburethral support (Kaufman I–crural crossover; Kaufman II–synthetic mesh tape that brings the crura together in the midline; Kaufman III–silicone gel device attached to the corpora cavernosa, which compresses the ventral urethra). While none of the Kaufman procedures gained widespread acceptance, they were minimally invasive and offered an alternative to leakage for the PPI patient. Although the Kaufman techniques only cured a minority of men, it is important to note that these techniques were practiced in an era of more severe PPI than is currently seen given today's more refined radical prostatectomy surgeries. In 1998, Schaeffer and colleagues described a novel bulbourethral sling procedure for PPI that used suburethral bolsters suspended from the rectus fascia by sutures.23 With this technique, the surgeon adjusts the sling tension until an intraoperative LPP exceeds 150 cm H2O. Stern and associates reported a 32% cure rate and a 35% pad-free rate in their retrospective questionnaire-based study of 95 men who underwent the procedure at a single institution.24 However, 20% of patients required revision, and bolster removal secondary to infection or erosion was necessary in 7%. Moreover, 19% of patients experienced chronic perineal numbness or pain, and two thirds of this group rated this problem as moderate or severe. 24

The introduction of the bone-anchored male sling system in 2000 (InVance, AMS) has transformed the operation into a minimally invasive procedure that can be performed on an outpatient basis. In this procedure, 6 bone screws are used for mesh fixation, obviating the abdominal incision and offering a reliable point of fixation. BONE-ANCHORED MALE SLING TECHNIQUE Intravenous cephalosporin is administered (unless the patient is allergic) prior to surgery. General anesthesia is recommended, as spinal anesthesia causes paralysis of the distal sphincter, potentially confounding the assessment of sphincteric resistance intraoperatively. The patient is placed in the lithotomy position and is prepared and draped in a sterile fashion. A 14F Foley catheter is introduced into the bladder to aid with urethral palpation. A 3.5-cm perineal incision is made, centered over the bulbous urethra. The bulbospongiosus muscle is exposed in the midline, and the medial aspects of the descending pubic rami are exposed bilaterally. Three titanium bone screws pre-loaded with 2 No. 1 polypropylene sutures are inserted with a bone drill in the anterior-medial aspect of each descending pubic ramus. The proximal bone screws are placed just beneath the junction of the descending ramus and the pubic symphysis, and the distal screws are inserted approximately 3 cm caudally, at the level of the bulbar urethra (Figure 1). Next, RLPP is measured via perfusion sphincterometry using a 14F catheter with the balloon inflated with 1 mL of water in the distal penile urethra. Perfusion sphincterometry is performed by connecting a bag of saline to the catheter via sterile tubing; the bag is elevated until fluid flows from the bag, through the drip chamber, and into the urethra.25 The RLPP is recorded as the height of the fluid column above the symphysis at which fluid flow commences. A 4 × 7-cm segment of silicone-coated polyester mesh (InteMesh, AMS) or polypropylene mesh (Ethicon, Somerville, NJ) is used as the sling. The bone-anchored sutures are passed through the sling 0.5 cm from the left edge, equally spaced along the width of the sling, and tied down to the bone (Figure 2). With the sling positioned over the bulbospongiosus muscle, the contralateral sutures are passed through the right side of the sling and secured with a single throw of the suture over a silk safety tie. RLPP is again measured, and sling tension is adjusted (Figure 3) by moving the right sutures more medially (tighter) or laterally (looser) until an RLPP of 60 cm H2O is achieved. The wound is irrigated and closed in 2 layers. The catheter is removed in the recovery room or the following morning for a trial of voiding. RESULTS In a University of Arizona cohort, 48 patients underwent male sling surgery between 2000 and 2003, with a minimum follow-up of 24 months.26 Average age was 67.6 ± 9.7 years. Six patients had previous artificial urinary sphincter implants, 8 had adjuvant XRT, 2 had primary XRT, and 9 had a previous collagen injection. All patients rated their incontinence as a "big problem" on the UCLA Prostate Cancer Index (PCI) instrument,27 and all used 3 or more pads daily. The median preoperative UCLA PCI incontinence score was 63 on a scale of 0-500, with a higher score indicating greater satisfaction. Preoperative mean RLPP was 27.3 ± 8.0 cm H2O, and patients used an average of 4.6 ± 2.1 pads per day. At a median follow-up of 48 months (range, 24-60 mo), the median UCLA PCI incontinence score improved to 343, and postoperative pad usage decreased to a mean of 1.0 ± 1.7 pads per day. 26 Overall, 31 (65%) of 48 patients were cured of their leakage (no problem, no pads), 7 (15%) were much improved (small problem, 1 pad), 3 (6%) were mildly improved (moderate problem, 2 pads daily), and 7 (15%) failed (big problem, ≥ 3 pads). In total, 38 of 48 (79%) were cured or much improved, and were "socially

continent," using 0 to 1 pad per day. Previous collagen injection and previous adjuvant XRT did not affect outcome; however, both patients with primary XRT failed, and 5 of 6 (83%) patients with a previous artificial urinary sphincter implant failed.26 In the group of patients who did not improve, 2 had primary XRT, 5 had a previous artificial urinary sphincter, and 1 had pelvic trauma. Complications included infection in 1 (2%) patient, which led to urethral erosion (patient had previous trauma and history of osteomyelitis); 7 cases (16%) of bothersome scrotal numbness/pain—all of which resolved within 3 months; and 2 (4%) instances of bone screw dislodgement postoperatively.26 Both of those patients presented with recurrent incontinence and underwent successful revision of the sling. Findings from urodynamic evaluation of a subgroup of 22 volunteer patients at an average of 25 months follow-up are summarized in Table 1. RLPP increased from a mean of 30.4 ± 15.7 cm H 2O to 59.9 ± 9.7 cm H2O following sling surgery (P<0.001).28 There was no significant change between intraoperative RLPP and RLPP on postoperative urodynamics (59.9 ± 9.7 vs. 56.7 ± 10.4 cm H 2O). No patient demonstrated BOO on urodynamics preoperatively, and none developed iatrogenic BOO following sling surgery. Average maximum flow rate (Qmax) postoperatively (17.7 ± 6.5 mL/sec) did not significantly differ from preoperative Qmax (19.2 ± 9.7 mL/sec), nor was there a significant change in detrusor pressure at Qmax (Pdet@Qmax), which averaged 40.3 ± 9.2 cm H2O preoperatively and 45.8 ± 14.7 cm H 2O postoperatively. The average postvoid residual urine volume was 17 ± 26 mL (range, 0-94 mL). While 4 patients demonstrated DO postoperatively, none developed symptomatic de novo urgency or urge urinary incontinence postoperatively. DISCUSSION The male suburethral sling has generated a tremendous amount of interest of late. This may be due to the desire for more minimally invasive alternatives for mild or moderately incontinent patients. The boneanchored technique we describe varies from some of the original compressive suburethral techniques (Kaufman I, II, III) in that it incorporates a reliable and solid point of fixation (descending pubic ramus) and uses synthetic material for compression. Furthermore, ideal patients presenting for current male sling therapy tend to have more mild incontinence than patients in the original Kaufman series.22 Current reported success rates for male sling surgery vary, according to the method of evaluation, the surgical technique, the patient selection criteria, and the length of follow-up. Evaluation method. While the ideal method of evaluation is not agreed upon, some measure of subjective satisfaction and objective leakage aids in interpreting results. We recommend administration of a validated self-administered questionnaire, such as the UCLA PCI, as well as a report of pad usage. The pad weight test, though cumbersome, would provide even more objectivity. As with any surgical treatment for SUI, it is difficult to draw conclusions with follow-up of less than 2 years. Surgical technique. The surgical technique used appears to affect outcome, as a range of success rates have been reported in the literature. Unlike females with SUI, male patients do not have significant urethral hypermobility; thus, the sling must be placed under tension to provide adequate compression. This tension can be maintained over time with a nondissolvable sling that is secured with permanent suture to the fixed pubic bones. The use of synthetic sling material29 is associated with a substantially higher success rate than is the use of organic sling material.30,31 Castle and colleagues from the Mayo Clinic recently reported a lower success

rate in their cohort.32 This may be because the surgeons retained the fatty tissue over the bulbospongiosus and, additionally, used a piece of porcine dermis between the urethra and the sling. A combination of fat necrosis and absorption of the dermis over time is likely to contribute to diminution of the compression provided by the sling over the bulbar urethra. Patient selection. It is vital to assess bladder contractility prior to sling surgery. Although the urodynamic follow-up does not document significant obstructive changes, the patient's bladder must be capable of generating a contraction strong enough to overcome the fixed resistance of the sling. This is best determined by a pressure-flow study. In patients with extremely low outlet resistance, voiding pressure may be particularly low. The continuous occlusion test is useful for quantifying detrusor contractility in such patients.33 Patients who have had primary pelvic XRT have a substantially higher failure rate than those who have not undergone this treatment,24,26 as do patients who have had prior explantation of an artificial urinary sphincter.29,32 Previous antegrade or retrograde collagen injection does not adversely affect the outcome of the bone-anchored sling,29 as the sling is placed distal to the site of collagen injection. Previous full-course XRT appears to decrease the efficacy of bulbourethral sling surgery, as recently reported by the groups from Northwestern University,24 Wayne State University,31 and the Mayo Clinic.32 In patients who have had previous artificial urinary sphincter explantation, the results of the bone-anchored sling appear somewhat inferior to those of men undergoing other sling surgeries as their initial surgical treatment.29,32 This decrement in efficacy is likely due to urethral atrophy and/or diminished urethral compliance, rendering the urethra more difficult to coapt with a noncircumferential sling. These patients are better served by the circumferential compression afforded by the artificial urinary sphincter, which has been shown to have satisfactory success rates in patients who have had full-course XRT and in those with previous artificial urinary sphincter surgery.34 The success rate for the bone-anchored male sling surgery is not adversely affected by adjuvant XRT for recurrent local prostate cancer or by prophylactic XRT for positive surgical margins.29 SLING FAILURE In the case of patients with suboptimal continence following sling surgery, we prefer to leave the previously placed sling in situ and place an artificial urinary sphincter cuff distal to the sling through a scrotal incision. This approach has 2 advantages. First, avoidance of the previous operative field minimizes dissection through potentially scarred tissue. Second, leaving the proximally placed sling as a partially effective compressive device is similar to performing a tandem-cuff artificial urinary sphincter procedure. In cases in which the surgeon elects to place the cuff transperineally, the previous sling neither renders the operation more difficult nor decreases efficacy of the artificial sphincter. In the authors' experience, the silicone-coated polyester is not well incorporated into the subcutaneous or periurethral tissue and is, therefore, easily removed. The bulbospongiosus muscle may then be split and dissected off the underlying spongy urethra without difficulty.

CONCLUSIONS The bone-anchored perineal sling has established itself as a safe and efficacious treatment for ISD in men, especially in those with SUI following RP. Prerequisites for sling surgery are significant ISD plus adequate detrusor contractility. At a median of 4 years follow-up, success rates are comparable to those achieved with the artificial urinary sphincter, with an acceptably low rate of complications and revisions. Patients

with a previous artificial urinary sphincter and those who have had primary XRT are less likely to achieve success. UROlogic
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The bone-anchored perineal sling offers a minimally invasive alternative to the artificial urinary sphincter for ISD in men with postprostatectomy incontinence. Prerequisites for sling surgery are significant ISD plus adequate detrusor contractility. Success rates are lower for men who have had an artificial sphincter and those who have had primary XRT


				
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