Background
The male urethral sling is an important treatment for addressing male incontinence from multiple causes and unlike the artificial urinary sphincter (AUS), the sling requires no manual dexterity, no significant mechanical parts, and no patient training. [1] Currently, Coloplast’s Virtue sling (utilizes four arm approach versus two) [2] and Boston Scientific’s AdVance Male Sling System [3] are two available options for male urethral slings. The InVance bone anchored sling (a product of former company American Medical Systems) has fallen out of favor due to risk of osteomyelitis. [4] The Argus slings from the international company Promedon have also been used in the past. [5] Data presented reflect all three slings as described above.
Indications
Sling procedures to treat male urinary incontinence are indicated for bothersome mild-to-moderate urinary incontinence due to irreversible intrinsic sphincter deficiency (ISD).
Contraindications
Absolute contraindications to sling procedures for male incontinence include the following:
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Severe incontinence that is not likely to be resolved with a sling procedure. A prospective study of 62 postprostatectomy patients with incontinence found that men with less than 423 g of daily leakage on a pad weight test prior to bone-anchored perineal sling placement were 6 times more likely to have a patient-defined successful outcome than those with higher pad weights. [6] Other authors advocate using a cutoff of 150 g on a 24-hour pad weight test. [7]
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Bladder disorders that can jeopardize renal function, such as decreased bladder compliance and vesicoureteral reflux at low intravesicular pressures
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Inadequate tissue integrity at the bladder neck or urethra. Patients may require bladder neck closure or urinary diversion.
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Active urinary tract infection
Relative contraindications to sling procedures for male incontinence include the following:
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Further need for transurethral procedures, such as in patients with bladder cancer or refractory vesicourethral strictures, because transurethral access might be impaired and repeated instrumentation can increase the risk of infection or erosion
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Previous AUS placement. However, slings do not preclude future placement of an AUS. [9]
In patients with metastatic prostate cancer, the potential benefits in quality of life in the context of performance status, life expectancy, and surgical risk should be carefully considered.
Technical Considerations
The initial evaluation of a man with urinary incontinence requires a detailed history, physical examination, urinalysis, and urine culture. Candidates for sling procedures usually require more workup as part of surgical planning.
The medical history should include questions on the type, degree, and severity of urinary incontinence. The past surgical history should be elicited. The presence or absence of incontinence and/or associated voiding symptoms before surgery and the onset of leakage after surgery should be documented.
Since continence often improves after radical prostatectomy, some authors recommend a one-year observation period, [7, 10] but, if a patient has severe or gravitational urinary incontinence with no improvement after 6 months, it is unnecessary to delay intervention, especially if cystoscopy shows a significant external sphincter defect. [11]
A voiding diary and pad test can help differentiate between stress and urge incontinence and document the degree of incontinence. Self-reported daily pad usage is only moderately correlated with the volume of urinary incontinence [12] ; a 24-hour pad weight test is an objective measure that may be helpful in directing appropriate therapy.
The physical examination should include a detailed examination of the abdomen, back, genitalia, perineum, rectum, and nervous system. The skin should be inspected for signs of breakdown or infection that need to be treated prior to surgery. Rectal sphincter tone and contraction should be assessed.
Laboratory examinations include urinalysis and culture. Serum creatinine and prostate-specific antigen levels should be evaluated to assess renal function and cancer status after prostatectomy.
Procedure planning
Cystoscopy is recommended in the evaluation of candidates for surgical correction of urinary incontinence, because unrecognized urethral pathology can complicate all surgical approaches. During cystoscopy, the degree of residual external sphincter function can be estimated.
Assessment of bladder capacity, compliance, and contractility is required when considering a sling procedure. Although a careful history and voiding diary can confirm the adequacy of bladder function, pressure-flow urodynamics can accurately assess bladder function, the type of incontinence, and severity. Usually, ISD would be identified in most cases.
If detrusor overactivity is found, patients should be carefully counseled about realistic expectations for a successful outcome. Reduced bladder compliance is also a concern because prolonged storage at high pressures might contribute to upper tract deterioration. Detrusor hypocontractility might indicate the need for an AUS if the detrusor function is insufficient to allow voiding against the fixed resistance of a compressive sling.
Complication prevention
Prophylactic antibiotics are given to prevent infection. Surgical approaches that avoid bone anchors would prevent bone-related complications such as osteitis and anchoring complications. Meticulous surgical technique, especially during sling tensioning, is important for the proper functioning of the sling.
Outcomes
In appropriately selected patients, the male urethral sling has been shown to be effective. [13, 14, 15] For example, some authors have demonstrated that preoperative severity of incontinence, low midurethral closure pressure, low abdominal leak point pressure, decreased urethral functional length, presence of detrusor overactivity, low Qmax on uroflow assessment, reduced bladder capacity and urethral disease may all be characteristics of patients who are poor sling candidates and those likely to fail. [16, 17, 18, 19, 20, 21] Grimsby et al [22] retrospectively reviewed 31 patients at a single institution over a ten year period who underwent a transobturator sling procedure and concluded that obesity was directly associated with sling failure. Interestingly, whether or not a surgical learning curve impacts outcomes, particularly for the AdVance sling, is controversial. [23, 24] Nonetheless, sling procedures still appear to be relatively effective.
Contemporary data continue to demonstrate the effectiveness of the male sling. [4, 5, 17, 18, 20, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51] Welk et al performed a contemporary review of male sling procedures for post prostatectomy incontinence. [30] Multiple sling designs were incorporated and variable definitions of success and follow up periods were noted in each study. Success rates were from 40-91% depending on the study. [30] In a review by Trost et al, the authors found success rates to be from 9-100%. [33] In addition to objective measures of success, subjective metrics such as quality of life improvements have also been noted. [5, 28, 41]
Pain, infection, problems with anchoring, paresthesias, and a number of other complications have been noted to occur following male urethral sling placement. [5, 8, 11, 26, 30, 52, 53, 54] In the review by Welk et al, infection rates were from 2-12% and usually required sling explantation, whereas erosion rates were 3-13%. [30] Urinary retention is uncommon and even when it occurs, patients tend to recover and go on to stay dry in the long term. [45] It has been noted in the literature that the dorsal nerve of the penis can potentially be injured (although rare) and should be taken into consideration with placement. [54]
An analysis of a US Food and Drug Administration database revealed that the most common adverse events associated with synthetic male slings were urinary incontinence (46.7%), sling erosion (9.1%), mechanical malfunction (8.2%), and pain/numbness (8.2%). The slings included in the database were the Advance or Advance XP sling (69.8%), InVance (15.5%), Virtue Quadratic (12.3%), or unknown (2.4%). [55]
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The bone-anchored InVance sling. Courtesy of American Medical Systems, Inc., ww.AmericanMedicalSystems.com.
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The transobturator AdVance sling. Courtesy of American Medical Systems, Inc., ww.AmericanMedicalSystems.com.
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The quadratic Virtue sling. Courtesy of Coloplast Corp.
