The Male Sling for Postprostatectomy Incontinence: Current Concepts and Controversies



The Male Sling for Postprostatectomy Incontinence: Current Concepts and Controversies


YING H. JURA

CRAIG V. COMITER



PREVALENCE OF POSTPROSTATECTOMY INCONTINENCE

The most common cause of stress urinary incontinence (SUI) in men is iatrogenic injury during prostate surgery. The rate of incontinence following surgery for benign prostatic hyperplasia is approximately 2% (1). In contrast, the risk of urinary incontinence is significantly higher following surgery for prostate cancer. In a questionnaire-based study by Stanford et al. (2), postprostatectomy patients were evaluated using a selfadministered questionnaire. Only 32% claimed total urinary control, 40% had occasional leakage, 7% had frequent leakage, and 2% suffered from no control at 2 years postoperatively (2). Although reports of postprostatectomy incontinence (PPI)
vary, contemporary cohort studies demonstrate that 1% to 5% of patients will ultimately undergo surgery for the management of their incontinence after radical prostatectomy (2,3,4,5).


RISK FACTORS FOR POSTPROSTATECTOMY INCONTINENCE

The surgical technique for radical prostatectomy (RP) has become relatively standardized, with improved instrumentation and visualization, especially following the adoption of robotic assistance. There are, however, recognized risk factors for PPI. These risk factors include age, preoperative continence status, preoperative voiding dysfunction, tumor stage, obesity, prior radiation or transurethral resection of the prostate, vascular disease, preoperative membranous urethral length, and postoperative radiation or cryotherapy (6,7,8,9,10,11,12,13,14). Although many of these risks may not be modifiable, they may alter cancer treatment choice.

The most predictive risk factors for PPI are preoperative urinary incontinence and voiding dysfunction. Stress incontinence in men who have not had prostate cancer surgery occurs at a baseline prevalence of 1.3% to 4.8% (15). Whereas urgency and overflow incontinence associated with bladder outlet obstruction may indeed resolve following surgery for this condition, preoperative SUI typically will not improve postoperatively (6). Rather, baseline intrinsic sphincteric deficiency (ISD), demonstrated either by the preexisting clinical sign of SUI or the urodynamic finding of low maximal urethral closure pressure, strongly predicts postoperative SUI (13,14). Preoperative bladder dysfunction also increases the risk of PPI, especially in those with neurogenic detrusor overactivity secondary to Parkinson disease, dementia, or spinal cord injury (7).




INDICATIONS FOR SURGERY

Surgical intervention is indicated for treating bothersome SUI due to ISD that fails to adequately improve following 12 months of conservative management. Most patients will experience improvement in leakage for up to 1 year following surgery, regardless of active (pelvic floor physiotherapy) or passive (observation) management (20).

Severity, effect on quality of life, and the ability of the patient to conservatively manage incontinence must be balanced against the risks of surgery. In addition, reasonable physician and patient expectations based on clinical efficacy, acceptable morbidity (severity, duration, and need for additional therapy), and the avoidance of serious complications are essential. Implantation of a surgical device should be undertaken with caution in patients with uncontrolled detrusor overactivity or decreased bladder compliance. In addition, those conditions that may require future transurethral management (i.e., urethral stricture or bladder neck contracture) are relative contraindications to outlet surgery because repeated instrumentation may put the patient at risk for device infection or erosion.

Due to lack of U.S. Food and Drug Administration (FDA)-approved pharmacotherapy for ISD, and generally poor efficacy of periurethral bulking agents (21), surgery remains the primary treatment modality for the management of PPI. Surgical approaches include implantation of an artificial urinary sphincter (AUS), or placement of a male sling (MS). This chapter will focus on the surgical technique of the most popular MS surgeries.


ARTIFICIAL URINARY SPHINCTER

In contrast to the low-pressure coaptation of periurethral bulking, the AUS relies on circumferential occlusion of the urethra using a pressurized inflatable cuff. For more than three decades, the AUS has represented the most efficacious treatment for male SUI treatment, with satisfaction rates typically greater than 80%, regardless of the degree of incontinence. The majority of men with PPI are appropriate candidates for AUS placement, with exception of those who may lack the mental faculties and manual dexterity to cycle the scrotal pump and properly work the system.


The AUS has been reported to have a predictably high success rate regardless of the degree of incontinence, even in the setting of detrusor dysfunction such as overactivity, or diminished vesical compliance (22). In men who had presumably normal storage function prior to RP, the urodynamic findings of detrusor overactivity or diminished compliance are most likely due to a supraphysiologic infusion rate of filling medium into a bladder that has experienced a prolonged underfilled state secondary to continual urinary leakage. Preoperative detrusor overactivity does not adversely affect resolution of SUI following AUS implantation, but persistent overactive bladder symptoms are common, and patients must be counseled accordingly (22). Detrusor hypocontractility does not adversely affect surgical success because the AUS is cycled to an “open” phase during voiding, with relief of urethral occlusion.

The AUS, however, has a nontrivial complication rate. It has revision rates of 8% to 45% and explantation rates of 7% to 17% due to mechanical failure, urethral atrophy, infection, and erosion (23,24). Despite high success rates, the high cost and high revision rates have inspired the search for less expensive, less invasive, and less complicated devices. In addition, patients are often apprehensive about a mechanical device that requires manipulation prior to voiding. The modern MS has been actively studied and refined over the past decade in an effort to minimize invasiveness and overcome these hurdles.


MALE SLING

Various slings are currently available for the treatment of PPI. With the recent withdrawal of the bone-anchored sling from the market, the most commonly used devices are the retrourethral transobturator sling (RTS), the quadratic sling, and the adjustable pubourethral sling.


RATIONALE FOR THE MALE SLING

The impetus for the design of the modern MS was to decrease the risk of device infection, urethral erosion, and urethral atrophy that can be associated with a circumferential urethral compression and to allow for spontaneous voiding without the need for device manipulation. The MS is a noncircumferential suburethral device that is placed with the aim of applying sufficient urethral occlusive pressure to prevent leakage yet permit normal spontaneous voiding without the need for device manipulation. Recent experience with the MS has taught several lessons regarding the management of PPI with sling surgery: (a) Adequate but not excessive tension is necessary for urethral compression and continence; (b) welldesigned synthetic materials have an acceptably low rate of infection and erosion; (c) adequate detrusor contractility is necessary to overcome the fixed resistance of certain slings; (d) various methods of sling fixation can achieve successful urethral compression; (e) there is no “best” sling for all patients—rather different patient types may be best treated with different slings; and (f) patients with more severe or total urinary incontinence appear to have a lower success rate with the MS than do patients with more mild to moderate degrees of incontinence (25,26).


RETROURETHRAL TRANSOBTURATOR SLING


Surgical Technique

The most commonly performed sling procedure for the treatment of PPI is currently the RTS. As the mechanism of action of this sling is thought to rely more on repositioning the prolapsed sphincteric urethra than on direct compression of the bulbar urethra, it is recommended that preoperative evaluation include the “repositioning” test to verify the presence of adequate residual sphincter function. Rehder’s group demonstrated that the ALPP increases on gently pushing the perianal midperineum in a cephalad direction (avoiding direct compression of the urethral bulb). Men with sufficient residual sphincter function (i.e., mild ISD) demonstrate passive sphincter closure with cystoscopically visible contraction of the striated sphincter on perineal elevation (27). This provocative maneuver, by increasing the “zone of coaptation,” augments pressure transmission within the functional sphincteric unit, and when demonstrated preoperatively, is predictive of a successful surgical outcome (28,29). In those men with adequate residual sphincter function, a retroluminal transobturator sling is appropriate.

The surgery is performed under general anesthesia with the patient in a lithotomy position. A negative urine culture is required prior to surgery. Intravenous cephazolin (or vancomycin plus gentamicin, if allergic) is given within 1 hour of surgery.

After the patient is prepared and draped in a sterile fashion, a 14Fr Foley catheter is passed per urethra to help identify the perineal portion of the urethra. A 3- to 4-cm midline incision centered over the bulbar urethra is made. The bulbospongiosus muscle is typically divided and dissected off the bulbospongiosum. The central tendon can be found after the bulbar urethral is exposed and a retractor is placed to isolate the urethra. By gently pulling the perineal urethra cephalad, the central perineal tendon is evident as it spans from the inferior aspect of the bulbar urethra to the perineum. With retraction of the inferior aspect of the perineal incision caudal, and countertraction of the perineal urethra cephalad, the central tending should be readily visualized. After the central tendon is identified, the fibrous portion is divided to allow approximately 2 to 4 cm of mobility of the urethral bulb (Fig. 46.1).

Small stab incisions are made in each groin/thigh crease, approximately 1 cm inferior and lateral to the insertion of the adductor longus tendon at the medial border of the obturator foramen. Helical needle passers are then passed through the stab incisions, through the obturator membrane, around the inferior pubic ramus, and out at the apex of the triangle formed by the bulbar urethra medially and the ischiopubic ramus laterally. The mesh sling is then connected to the needle passers. The needle passers are rotated back along the insertion pathway to pull the sling back through the obturator foramen and out the stab incisions. The sling should be centered over the urethra. Four interrupted 3-0 polyglycolic acid sutures are then placed to secure the midportion of the sling to the bulbospongiosum just distal to the central tendon. Fixation of the sling to the periurethral tissue prevents “slippage” of the sling too far proximally and actually off the posterior aspect of the urethra, which can reduce sling efficacy.







FIGURE 46.1 Identification of the central perineal tendon, aided by upward traction of the perineal portion of the urethra. Detachment of this tendon permits proximal urethral relocation.

Only gold members can continue reading. Log In or Register to continue

Stay updated, free articles. Join our Telegram channel

Apr 24, 2020 | Posted by in UROLOGY | Comments Off on The Male Sling for Postprostatectomy Incontinence: Current Concepts and Controversies

Full access? Get Clinical Tree

Get Clinical Tree app for offline access