INTRODUCTION — Stress urinary incontinence (SUI) occurs when an increase in intraabdominal pressure exceeds urethral closure pressure, resulting in the involuntary leakage of urine. This may occur with physical exertion, sneezing, or coughing [1,2].
This topic will discuss the process of choosing a type of midurethral sling for females with SUI who have not had a prior anti-incontinence surgery. Choosing between midurethral slings and other procedures, nonsurgical management of SUI, treatment of recurrent SUI, and diagnosis and treatment of other types of urinary incontinence are discussed separately.
●(See "Female stress urinary incontinence: Choosing a primary surgical procedure".)
●(See "Female urinary incontinence: Evaluation".)
●(See "Female urinary incontinence: Treatment".)
●(See "Stress urinary incontinence in females: Persistent/recurrent symptoms after surgical treatment".)
In this topic, when discussing study results, we will use the terms "woman/en" or "patient(s)" as they are used in the studies presented. However, we encourage the reader to consider the specific counseling and treatment needs of transgender and gender diverse individuals.
PREVALENCE AND TREATMENT OPTIONS — The prevalence of stress urinary incontinence (SUI) among adult women in the United States is approximately 46 percent and varies by age and race [3,4].
The treatment of SUI includes both conservative (eg, weight loss, vaginal devices, pelvic floor muscle exercises) and surgical options. Minimally invasive midurethral synthetic slings have become the preferred surgical procedure for most women [5]. The tension-free vaginal tape was introduced in 1995 followed by the transobturator midurethral sling in 2001 [6]. The transobturator approach was designed to avoid some of the complications of a retropubic insertion (eg, bladder perforation, vascular injury, bowel injury). Since that time, other devices have been developed, with a variety of introducer mechanisms and mesh types.
TERMINOLOGY — There are several types of sling procedures for treatment of SUI in women (table 1). These procedures vary by the location of the sling and by the sling material. Collectively, these slings are referred to as suburethral slings, which is a sling that is inserted through a small vaginal incision and attached to another structure in the pelvis for the purpose of supporting the urethra. Suburethral slings may be either bladder neck or midurethral slings.
●Midurethral sling – A suburethral sling that is placed at the level of the midurethra in a tension-free manner. These slings are made of synthetic mesh.
•Retropubic midurethral slings (eg, tension-free vaginal tape [TVT]) are inserted through the retropubic space and exit through the abdominal wall in the suprapubic area (figure 1).
•Transobturator midurethral slings (eg, TVT Obturator) are inserted through the two obturator foramens and exit through the skin of the groin area (figure 2).
•Single-incision midurethral slings (also referred to as mini-slings) differ from full-length retropubic and transobturator slings in two ways: they are shorter (approximately 8 cm rather than 40 cm) and they require only a vaginal incision, and not an abdominal incision. Different types of these slings may be placed in a retropubic (anchored to the urogenital diaphragm) or transobturator fashion (anchored to the obturator internus muscle).
●Pubovaginal sling – A suburethral sling that is placed at the level of the proximal urethra and bladder neck (figure 3). This procedure uses autologous fascia, tissue, or biologic graft to support the urethra to an abdominal wall fixation site through both vaginal and abdominal incisions.
Bladder neck slings are when the arms of the sling material are affixed to Cooper's ligament or pubic bone rather than the anterior rectus fascia [7].
FULL-LENGTH SLINGS
Retropubic versus transobturator midurethral slings — When a midurethral sling surgery is planned, the surgeon and patient must decide between a retropubic or transobturator sling. Both are widely used, and the treatments appear to be comparable, with differing efficacy and risk profiles [8-17]. In our practice, we counsel the patient about the different efficacy and types of adverse effects associated with each type of sling and make the choice of sling based upon patient preference. Patients who desire a slightly higher probability of efficacy and are willing to accept an increased risk of adverse events usually choose retropubic midurethral sling. Patients who desire less risk of adverse events and are willing to accept a slightly lower probability of efficacy choose transobturator midurethral sling.
●Retropubic slings have slightly higher efficacy at the cost of greater rates of bladder perforation, bowel injury, more short-term postoperative suprapubic pain, and postoperative voiding dysfunction, which could require sling release [18,19].
●Transobturator slings have a slightly lower efficacy and more short-term postoperative groin pain. However, they are associated with less voiding dysfunction than retropubic slings [18,19].
Efficacy — Retropubic slings appear to have slightly higher short-term efficacy; longer term differences are less clear [17,19,20]. Supporting data include:
●Network meta-analysis – A 2019 network meta-analysis of over 21,000 women from 175 trials, obtained from earlier meta-analyses and subsequent trials, reported SUI cure rates of 89.1 percent for retropubic midurethral sling and 64.1 percent for transobturator midurethral sling [19]. Compared with retropubic midurethral sling, the odds ratio of improvement for transobturator midurethral sling was 0.76 (95% CI 0.59-0.98). However, most of the included studies were limited to approximately 12 months of follow-up.
●Meta-analysis – A 2017 meta-analysis including data from 55 trials of midurethral sling operations for SUI in women reported no difference in subjective cure rates at one year [17]. Specifically, subjective cure rates of 62 to 98 percent were reported in the transobturator sling group and 71 to 97 percent in the retropubic sling group at one year. Fewer studies reported longer term data (greater than five years), but subjective cure rate remained similar between the two groups, although the transobturator approach had a higher rate of repeat surgery after five years.
●Trial data – One of the trials included in the above network meta-analysis, the Trial of Midurethral Slings (TOMUS), also reported five-year follow-up data for 597 women randomly assigned to either sling procedure [8,10]. Additional important findings from the five-year follow-up included [10]:
•More women reported incontinence over time regardless of sling type. There was a nonsignificant trend toward higher incontinence rates for transobturator versus retropubic sling procedures (56 versus 49 percent). It is not known if this incontinence increase was a result of the surgical procedure, the underlying incontinence process, or natural aging.
•Patient-reported outcomes for quality of life, sexual function, and global assessment of improvement decreased with time in both treatment groups but remained greater than presurgery measurements. Compared with retropubic slings, women with transobturator slings reported more sustained improvement in urinary symptoms, quality of life, and sexual function despite the slightly lower treatment success rate.
•New mesh exposures continued to occur throughout the five-year follow-up, but the overall rate of mesh exposure remained low at 1.7 percent.
Risk of repeat incontinence surgery — The body of evidence suggests that reoperation for recurrent SUI is less likely following retropubic sling insertion [18,21,22].
●Five-year data – A five-year cohort study of over 8600 Danish women reported that women with the transobturator slings were twice as likely to undergo reoperation as women with retropubic slings [21]. However, a subsequent study of data from the same Danish registry reported absolute five-year reoperation rates were overall low and estimated to be 6 percent for retropubic slings and 9 percent for transobturator slings.
●Eight-year data – A covariate-matched cohort study comparing patients with retropubic and transobturator slings reported that eight-year cumulative incidence rates of reoperation for SUI were 5.2 (95% CI 3.0-7.4) and 11.2 (95% CI 6.4-15.8) percent, respectively, a nonsignificant difference [18]. Longer term studies are emerging.
●Seventeen-year data – A study that followed 46 out of 52 women from Switzerland and Italy with retropubic slings for 17 years reported overall satisfaction and negative stress test rates of 89 and 91 percent, which are similar to the one-year cure rates above [22]. However, 15 (29 percent) of these women reported de novo overactive bladder and were taking antimuscarinic or beta agonist therapies, and 4 percent reported persistent voiding dysfunction that was observed.
Complication comparison — In general, midurethral slings have low complication rates. In a database study of 9910 isolated sling procedures (combined retropubic and transobturator), the readmission and reoperation rates were 0.6 and 0.8 percent [23]. However, the two sling approaches have been associated with somewhat different surgical complications. Overall, the majority of adverse events appears higher using the retropubic approach than the transobturator approach [18,20,24]. The network meta-analysis of over 21,000 women from 175 trials demonstrated that transobturator midurethral sling had a higher rate of repeat procedures and a higher occurrence of groin pain than retropubic midurethral sling. Conversely, retropubic midurethral sling was associated with a higher rate of suprapubic pain, as well as a higher rate of major vascular complications, bladder or urethral perforation, and voiding difficulties than transobturator midurethral sling. The rate of tape or mesh erosion or extrusion was similar between the two procedures [19].
Reduced operating time, hospital stay, and blood loss have also been reported with transobturator compared with retropubic slings [8,11,13,20,24,25]. Additionally, retropubic sling placement may increase risk of postoperative urinary retention and bowel injury, particularly in women with prior abdominal or pelvic surgery (including abdominal and inguinal hernia repair) [18,26-30]. The covariate-matched cohort study demonstrated that women in the retropubic group had an increased risk of subsequent surgery for urinary retention (hazard ratio 8.11, 95% CI 1.08-61.17) [18]. (See "Surgical management of stress urinary incontinence in females: Retropubic midurethral slings", section on 'Bowel injury'.)
Additionally, higher rates of de novo dyspareunia have been reported with transobturator slings [31]. However, whether the transobturator and retropubic approaches have different effects on sexual function is unclear [31-34]. Further study is needed to evaluate this issue.
Intrinsic sphincter deficiency — Some data suggest that the retropubic sling is more effective than the transobturator sling for women with intrinsic sphincter deficiency (ISD) [12,15,35,36]. ISD has been defined as either a maximum urethral closure pressure (measured both with the bladder empty and at capacity) of 20 cm H2O or less and/or a pressure rise from baseline required to cause incontinence (change in Valsalva or cough leak point pressure) of 60 cm H2O or less. (See "Urodynamic evaluation of women with incontinence", section on 'Urethral pressure profile'.)
In one study, 164 women diagnosed with ISD, with or without concomitant pelvic organ prolapse repair, were randomly assigned to receive either a transobturator or retropubic sling [37]. Of the 138 patients assessed at six months with urodynamic studies, more women in the transobturator group had urodynamic stress incontinence compared with the retropubic group (45 percent versus 21 percent). Nine women in the transobturator group needed repeat sling surgery compared with none in the retropubic group.
Mixed urinary incontinence — Women with mixed urinary incontinence can be treated with midurethral slings, particularly if a significant SUI component is present [38-41]. A 2011 systematic review and meta-analysis of five RCTs that included data on transvaginal and transobturator slings in women with mixed urinary incontinence reported similar subjective cure rates at 6 to 33 months follow-up for the two procedures (odds ratio 0.9, 95% CI 0.63-1.27) [41]. In this review, the cure rates of urge incontinence (30 to 85 percent) were more variable than for stress incontinence (85 to 97 percent) and declined over time.
Choosing a type of retropubic sling — There are two main variations of full-length retropubic midurethral sling, based upon the initial incision site and direction of insertion:
●Bottom-to-top – Two needle trocars are inserted through a vaginal incision and passed through the retropubic space, exiting at the abdominal wall (eg, the original TVT device).
●Top-to-bottom – Two needle trocars are inserted through abdominal incisions and passed through the retropubic space, exiting through a vaginal incision (eg, SPARC).
The choice between these two variations of retropubic slings is discussed separately. (See "Surgical management of stress urinary incontinence in females: Retropubic midurethral slings", section on 'Comparison of insertion routes'.)
Choosing a type of transobturator sling — There are two variations of transobturator midurethral sling procedures, which vary by direction of trocar insertion:
●Inside-out – The trocars are passed from a midurethral vaginal incision to exit through bilateral groin incisions (TVT Obturator).
●Outside-in – The trocars are passed from bilateral groin incisions to exit through a midurethral vaginal incision (Aris, Obtryx).
The choice between these two variations of transobturator slings is discussed separately. (See "Surgical management of stress urinary incontinence in females: Transobturator midurethral slings", section on 'Choosing a type of transobturator sling'.)
SINGLE-INCISION SLINGS — Single-incision slings (eg, Solyx, Ajust and TVT-Secur; also referred to as mini-slings or mini-tapes) differ from full-length retropubic and transobturator slings in two ways: they are shorter (approximately 8 cm rather than 40 cm) and they require only a vaginal incision, and not an abdominal incision. Different types of these slings may be placed in a retropubic (anchored to the urogenital diaphragm) or transobturator fashion (anchored to the obturator internus muscle).
Comparison of single-incision and full-length slings
●Advantages – Purported advantages of single-incision slings are less tissue disruption, less risk of visceral injury, and fewer patients requiring catheter use postoperatively than retropubic or transobturator approaches. The success of these goals has not yet been established.
●Sling types – There are two variations of single-incision slings, based upon their anatomic path and the site to which they are attached:
•U-shaped (U) position into the connective tissue of the urogenital diaphragm
•Hammock (H) position into the obturator internus muscle
●SUI cure rate – Most studies regarding single-incision sling procedures report an SUI cure rate of 74 to 95 percent at 6 to 12 months postoperatively [42-48]. Two studies that followed patients with SUI for 36 months after sling placement reported continence rates of 84 to 90 percent [49,50]. There are few longer term data.
●Comparison with other sling types – Given the available evidence, for women planning primary midurethral sling surgery, we suggest a full-length rather than single-incision sling. However, if avoiding postoperative pain is a prioritized concern, short-term studies suggest a single-incision sling may be an acceptable alternative. Patients should be counseled about synthetic materials as well as the risks of adverse events for each type of sling.
•Favoring full-length slings – A systematic review and meta-analysis of 15 randomized trials comparing single-incision with full-length midurethral slings found that objective (odds ratio [OR] 4.16, 95% CI 2.15-8.05) and subjective cure (OR 2.65, 95% CI 1.36-5.17) were both significantly better for full-length slings [11]. The rate of overactive bladder symptoms was similar for single-incision and obturator slings, but was slightly higher for retropubic slings (single-incision: 5.4 versus obturator: 5.3 versus retropubic: 6.9 percent). The rate of exposure of the sling was similar for single-incision and obturator slings, but lower for retropubic (2.2 versus 2.0 versus 1.4 percent). A major limitation of this analysis is that the majority of studies used a type of single-incision sling (TVT-Secur) that is no longer available in many regions; thus, these data are indirect regarding other single-incision slings.
•Similar efficacy of sling types – Since the above review, two additional randomized trials, including over 350 combined participants, compared a single-incision sling with a transobturator sling and reported similar efficacy, safety, and mesh erosion rates between the two procedures. In addition, the studies noted that those who underwent a single-incision sling procedure reported lower intensity and a shorter duration of postoperative pain after two and three years of follow-up [51,52].
Adjustable slings — Adjustable midurethral slings (eg, Remeex) are a subsequent development that allow postoperative adjustment of sling tension. Comparative data regarding this sling are limited and include small studies. The Remeex adjustable sling was evaluated in a population of 38 patients with valsalva leak point pressures <60 cm H2O or maximal urethral closure pressures less than 20 cm H2O [53]. A total of six patients had these slings adjusted according to their symptoms: three in the immediate postoperative period and three in the late postoperative period. At the end of the study, all patients were reported to be asymptomatic for SUI. A later study of 157 patient with primary SUI who underwent insertion of an adjustable obturator tape and had 12-month follow-up reported objective and subjective cure rates of 96 and 98 percent, respectively [54].
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Incontinence surgery in women" and "Society guideline links: Urinary incontinence in adults" and "Society guideline links: Gynecologic surgery".)
INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
●Basics topics (see "Patient education: Urinary incontinence in females (The Basics)" and "Patient education: Surgery to treat stress urinary incontinence in females (The Basics)")
●Beyond the Basics topic (see "Patient education: Urinary incontinence treatments for women (Beyond the Basics)")
SUMMARY AND RECOMMENDATIONS
●Definition – Stress urinary incontinence (SUI) is the involuntary leakage of urine on effort or exertion, or on sneezing or coughing. For many women, midurethral sling placement is the procedure of choice. (See 'Introduction' above.)
●Comparison of retropubic and transobturator slings – Retropubic full-length slings may have slightly higher continence rates compared with transobturator slings but are associated with higher risk of intra- and postoperative complications. Bladder perforation and voiding dysfunction are more likely to occur in women who have undergone a retropubic sling procedure, while short-term groin pain is associated almost exclusively with transobturator slings. In our practice, we counsel the patient about the efficacy and potential adverse effects associated with each type of sling and make the choice of sling based upon patient preference. (See 'Retropubic versus transobturator midurethral slings' above.)
●Comparison of full-length and single-incision slings – For women planning midurethral sling surgery, we suggest a full-length rather than single-incision sling (Grade 2B). However, a single-incision sling may be a reasonable alternative for those who prioritize avoiding postoperative pain. Patients should be counseled about risks of adverse events for each type of sling. (See 'Comparison of single-incision and full-length slings' above.)
●Adjustable sling – Adjustable midurethral slings are single-incision slings which allow postoperative adjustment of sling tension and are a new development. These slings require further evaluation. (See 'Adjustable slings' above.)
