The therapeutic options for management of stress urinary incontinence can be conservative, pharmacological or surgical. The treatment of patients with stress urinary incontinence should be tailored to the individual to optimize care. A multitude of surgical techniques have emerged to treat this condition in recent years. The objective of the present review was to present an overview of current practice in the management of stress urinary incontinence while considering the evidence supporting the clinical effectiveness of these procedures.
Urinary incontinence is a prevalent debilitating and distressing condition in women that is often under-reported and undertreated. The condition can result in social isolation, psychological impairment, restriction of physical activities and is associated with sexual dysfunction.[2-4] The International Continence Society defines SUI as an involuntary leakage of urine on exertion effort, coughing or sneezing. A postal survey carried out across four European countries with over 17 000 participants found that 35% of women had experienced incontinence, with SUI being the most prevalent type of incontinence. It has been reported that 50% of women presenting with urinary incontinence will exhibit pure SUI, whereas 30% experience MUI. Urinary continence is maintained through co-ordination between the bladder, urethra, pelvic floor muscles and the nervous system. The development of SUI is attributable to two recognized mechanisms, which can coexist. Hypermobility can result in significant displacement of the urethra and bladder neck during exertion. The second mechanism responsible for SUI is ISD. Anatomically, the urethra is supported by the levator ani muscles, anterior vagina, endopelvic fascia and the arcus tendineus muscles providing a hammock-like support system. The support system can be damaged when stretched, resulting in urethral displacement and subsequent SUI. Typically, such defects can result from vaginal delivery, where the support system is strained. Hypermobility can develop from the loss of anatomical support and increased intrabdominal pressure, which results in displacement of the proximal urethra and bladder neck from the pelvis, resulting in increased pressure being transmitted to the bladder. Uneven pressure transmission and opening of the bladder neck results in urine leakage during exertion. The second mechanism responsible for SUI is ISD, where the sphincter is unable to maintain resting urethral closing pressure.
Other risk factors that have been associated with SUI include smoking, obesity and aging. A gene that has significant linkage for a predisposition to pelvic floor disorders including SUI has also been found.
In the era of evidence-based medicine, healthcare professionals are obliged to carefully evaluate the evidence supporting their practice. Some urogynecologists might be inclined to utilize surgery as the first-line treatment for SUI, whereas most prefer to start with a conservative approach. Efforts should be made to inform patients on the benefits and risks associated with treatment options. The treatment of stress urinary continence can be stratified into conservative, pharmacological and surgical methods. The objective of the present review was to discuss the evidence supporting the key methods used to treat SUI in current clinical practice.
Blavius and Olsen developed a classification of stress urinary incontinence based on fluoroscopic images. This effort established a method for defining patients with different types of SUI, which are now known to have characteristic findings on videourodynamics and abdominal leak-point pressure measurement. A classification system for SUI is summarized in Table 1. Type 2 SUI develops from urethral hypermobility, whereas type 3 SUI develops from ISD. Although the clinical parameters for ISD are loosely defined as a Valsalva leak-point pressure <60 cmH2O or a maximal urethral closure pressure <20 cmH2O, consensus is lacking.
Table 1. Summary of the different types of SUI
Type of stress incontinence
Findings on videourodynamics
Abdominal leak-point pressures
The urethra and vesical neck are closed at rest, located at or above superior border of pubic symphysis.
On coughing or straining, the vesical neck and urethra open with no evidence of leakage of urine.
Urine loss in the absence of urethral hypermobility
The vesical neck is closed at rest, located at or above inferior border of pubic symphysis.
Coughing or straining result in the vesical neck and proximal urethra opening and descending less than 2 cm
Urinary leakage is present
Urethral hypermobility present
The vesical neck is closed at rest, located above the margin of symphysis pubis
Coughing or straining results in the vesical neck and proximal urethra descending more than 2 cm.
Leakage of urine and a cystocele is present.
Urethral hypermobility present
The vesical neck is closed at rest, located below the margin of the symphysis pubis.
Coughing or straining results in the proximal urethra opening.
Leakage of urine is present
Intrinsic sphincter dysfunction
The vesical neck and urethra are open even in the absence of strain.
Leakage of urine is present due to contributory factors, such as gravitational and minimal intravesical pressure.
Assessment of patients presenting with urinary incontinence should include a focused medical history and examination. The history should elicit information regarding the characterization of incontinence, severity of symptoms, frequency and impact on lifestyle. Questionnaires can be used as a subjective measurement of the severity of symptoms. Objective measurements can be obtained from voiding diaries, pad tests, stress test, Q-tip test, abdominal leak pressure measurements and/or urodynamic testing. The role of UDS testing before surgery is unclear. Most urogynecologists and urologists consider UDS essential before surgery in SUI with or without other symptoms. Most, however, recognize the need for further research, and showed a willingness to recruit into multicenter trials addressing this question. The Value of Urodynamic Evaluation study recently published their findings from a multicenter randomized (non-inferiority) trial, where women with uncomplicated SUI either had a clinical evaluation alone or in addition, had UDS before surgery. The primary outcome was measured at 12 months using validated questionnaires: the Urogenital Distress Inventory and the Patient Global Impression of Improvement. In the study, 315 women were allocated to each arm of the trial, where treatment success was 77.2% and 76.9%, respectively, in the clinical evaluation and UDS + clinical evaluation group. In essence, routine urodynamic evaluation can be omitted before surgical management of uncomplicated SUI. Careful office evaluation of these women should include thorough history taking, pelvic examination including a cough test, uroflowmetry and a postvoid residual scan. However, women with pre-existing voiding dysfunction and failed incontinence surgery will still need urodynamics.
Current NICE guidelines recommend that intensive supervised PFMT for 3 months should be offered as a first-line treatment to women suffering from SUI or stress predominant MUI. Furthermore, PFMT should be offered to women in their first pregnancy as a preventive strategy for urinary incontinence. Compliance is often poor, and this technique requires motivated patients. A Cochrane review has analyzed the benefit of PFMT in urinary incontinence in women. However, the analysis involves a heterogeneous group of patients with variations in the type of incontinence, training regimens and outcome measurements. Women who undertook PFMT were more likely to be cured or have improved symptoms (29–67%) with better continence-specific quality of life. Furthermore, the benefits of PFMT were seen more markedly in patients with SUI than other forms of incontinence.
According to NICE guidelines, biofeedback or electrical stimulation should only be considered in patients with the inability to actively contract their pelvic floor muscles. Morkved et al. carried out a RCT of 103 women with stress incontinence, mean age of 46.6 years (range 30–70 years) who either underwent 6 months of PFMT alone or PMFT with concurrent biofeedback. Although patients reported a reduction in urinary leakage after treatment, there was no statistical significant difference between the two groups. Similarly, studies comparing electrical stimulation against PFMT have failed to show a statistically significant advantage with electrical stimulation alone.[18, 19]
Several non-surgical devices have been used to treat SUI. These include pessaries to elevate the vesico-urethral angle, weighted vaginal cones and urethral occlusive devices. Nine recent studies of these were scrutinized. The median corrected subjective cure/improvement rate was 63% for the vaginal and 43% for the urethral devices. The latter group have a high percentage of side-effects, such as urinary tract infection and migration of the device into the bladder, and related drop-outs. The vaginal devices currently available compete favorably with other non-surgical forms of therapy for stress incontinence in terms of efficacy and safety.
Duloxetine, a selective serotonin and noradrenaline reuptake inhibitor, is the only licensed drug used in the treatment of SUI in Europe. The mechanism of action is presumed to be mediated through Onuf's nucleus in the sacral spinal cord, which contains a high density of noradrenaline and serotonin receptors. In the presence of noradrenaline and serotonin, the pudenal neurons located in the Onuf's nucleus are stimulated, causing contraction of the urethral sphincter. Duloxetine inhibits the reuptake of noradrenaline and serotonin into the presynaptic terminal augmenting urethral sphincter muscle tone.
The available evidence suggests that duloxetine treatment can significantly improve the quality of life of patients with SUI while they are receiving treatment. Adverse effects are common, but not serious. Approximately one in three participants allocated to duloxetine treatment reported adverse effects (most commonly nausea) related to treatment, and approximately one in eight allocated to duloxetine stopped treatment as a consequence. Duloxetine was withdrawn in the USA in 2005 because of concerns regarding liver toxicity and suicidal events. NICE recommends that duloxetine should not be used routinely as a second-line treatment for SUI, though it can be considered if women prefer pharmacological treatment options as an alternative to surgery or if they unsuitable candidates for surgical intervention. A multicenter RCT concluded that combined PFMT and duloxetine are significantly efficacious compared with either treatment alone or no treatment.
Surgical approaches for SUI should be individualized to the patient and dependent on the type of SUI. For urethral hypermobility, surgery should reinforce support for the sphincter unit. Procedures that have been utilized to treat this form of SUI include bladder neck suspension, pubovaginal slings and midurethral sling surgeries. When SUI develops from ISD, the aim of surgery is to restore urethral coaptation. Approaches that have been utilized to regain sphincter function include pubovaginal slings, periurethral bulking agents and or artificial urinary sphincter. Surgeons should inform patients of the risk and success rate associated with a particular procedure, and patients should play an active role in deciding treatment. Over the years, numerous surgical techniques have been developed to treat SUI with variable subjective and objective cure rates. A retropubic midurethral sling seems to be an effective primary surgical treatment for urethral hypermobility, as well as ISD. An overview of various surgical procedures for SUI is provided in the following sections.
The procedure can be executed using either an open approach or a laparoscopic approach. Kinn et al. reported favorable long-term results for the Burch procedure. At 2 months postoperative follow up, 88% of patients in their study reported continence with a failure rate 7%, whereas follow up at a median of 5 years (range 39–102 months) showed that 78% of patients remained continent with an 11% failure rate. A 10–20-year follow up of patients showed a chronological decline in cure rates, which seemingly plateaued at 10–12 years with cure incontinence rates of 69%. In a population-based analysis of women aged 18–64 years, the Burch procedures had the lowest 9-year cumulative incidence of repeat SUI surgery. The other attractive benefit is that there is no risk of sling exposure or erosion. Laparoscopic colposuspension has the advantage of being less invasive, and is associated with shorter recovery times with no significant differences in cure rates. However, it remains technically challenging, and is dependent on the skill of the surgeon.[28, 29]
Tension-free vaginal tape
The TVT procedure is widely acknowledged as the current gold standard surgical treatment for SUI. The procedure is minimally invasive, with a shorter operative duration and can be undertaken electively as a day case. TVT was first pioneered by Ulmstein in 1996 using a polypropylene mesh. A synthetic sling is inserted through an anterior vaginal incision at the midurethra through a retropubic approach. On increasing abdominal pressure, the tape tightens around the urethra maintaining continence.
TVT procedures have subjective cure rates that are comparable to retropubic colposuspension (at 12 months RR 0.96, 95% CI 0.90–1.03; at 5 years RR 0.91, 95% CI 0.74–1.12) with fewer perioperative complications, less postoperative voiding dysfunction, shorter operative time and hospital stay, but significantly more bladder perforations (6% vs 1%, RR 4.24, 95% CI 1.71–10.52). There was conflicting evidence about the effectiveness of minimally-invasive synthetic suburethral sling operations compared with laparoscopic colposuspension in the short-term. TVT operations had significantly less de novo urgency and urgency incontinence, shorter operating time, hospital stay, and time to return to daily activities. A key complication related to tape procedures involves infection and erosion, which can be associated with the composition of the tape and its pore size. NICE guidelines recommends only type 1 macroporous polypropylene mesh for this procedure. A study by Bai et al. showed that TVT was effective in treating SUI from ISD and non-ISD patients. The cure rates of the two groups (ISD vs non-ISD) at 1 month follow up (87.0 vs 100%; P = 0.0053) showed a significant difference, but no significant differences were found at 3, 6 and 12 months.
Using the TOT procedure approach, the surgeon anchors the tape through the obturator foramen. Two methods have evolved based on the direction of approach. The inside-out technique involves passing the needle with the tape from an incision inside the vagina through the obturator foramen to the outside of the body in the groin region. The alternative outside-in approach penetrates the needle laterally to a suburethral position. A comparison of both approaches yielded no significant difference in efficacy or morbidity. The E-TOT RCT compared the effectiveness between inside-out and outside-in TOT approaches. There was no significant difference in patient-reported success rate at 3-year follow up, with an overall success rate of 73.1% (inside-out 73.18% vs outside-in 72.3%, OR 0.93). Comparison of overall success rates between 1 and 3 years showed a significant drop at 3 years for this cohort of women: 81.3% versus 73.1% (P = 0.005).
The meta-analysis of RCT and prospective cohort studies reported good cure rates of the stress component (85–97%), and lower (30–85%) and declining cure rates of urge incontinence over time after MUS procedures in MUI. Sexual function and/or coital incontinence in the absence of prolapse seem to improve after continence surgery. Results from prospective cohort studies and RCT suggest a significant reduction in coital incontinence post-surgery (OR 0.11, 95% CI 0.07–0.17).
The overall subjective cure rate per meta-analysis of prospective cohort studies after MUS (which was TVT in most of the included studies) for recurrent SUI after any previous surgery was found to be 78.5% (95% CI, 69–88%) at the follow up of 29.72 ± 29.49 months. The subjective cure rate following MUS surgery after previous failed MUS was 73.3% (95% CI 55–97%) at the follow up of 15.7 ± 7.7 months.
Surgery for pelvic organ prolapse (especially the anterior compartment) might unmask occult SUI in up to one-third of women. The question is whether preoperative identification of occult (and overt) SUI requires an anti-incontinence procedure at the time of prolapse repair is debatable. So far, only one randomized study evaluated the long-term follow up for SUI in patients with or without concomitant Burch's colposuspension at the time of prolapse surgery. They did not find any significant difference in urinary incontinence in both the groups. In the Outcomes Following Vaginal Prolapse Repair and Midurethral Sling trial, women assigned to the sling group had lower rates of SUI 3 months postoperatively (23.6% vs 49.4%), with benefits maintained at 12 months. However, the sling group also had higher rates of complications, including bladder perforation (6.7% vs 0%) and voiding dysfunction (3.7% vs 0%) in comparison with the women in the same group. The Outcomes Following Vaginal Prolapse Repair and Midurethral Sling trial findings add to the evidence from an earlier trial, the Colpopexy and Urinary Reduction Efforts trial, in which a prophylactic Burch colposuspension at the time of abdominal sacrocolpopexy reduced the symptoms of postoperative SUI and did not increase intraoperative or postoperative complications.
Similar subjective cure rates have been reported between TVT and TOT procedures, though bladder perforation, pelvic hematomas and voiding difficulties were less common in the TOT group, whereas postoperative groin pain and mesh exposure were more common in the TVT group.[41-44] Figure 1 shows the risk of complications associated with TOT and TVT approaches from a meta-analysis. In a recent RCT of TVT versus TOT, the authors noted that although there was no significant difference between the cure rates, a palpable tape was noted more frequently in the TOT group (RR 0.22 95% CI 0.13–0.3; P < 0.001). Ross et al. evaluated the economic benefit of TOT against TVT in a RCT. TOT had a non-significant cost–savings benefit in comparison with TVT based on a study of a total of 194 women followed to 1 year post-surgery. However, the results should be interpreted with caution, as the economic benefit was evaluated at 1 year, which excludes any representation of financial burden that could incur from complications experienced in the long term. The authors were concerned that palpable tape present could lead to long-term complications, such as erosions that might require treatment, hence any economic savings by the TOT might be premature when considering long-term outcomes. A comparison of both procedures over the long term is essential to show that efficacy is maintained and complication rates remain low in patients who undergo TVT.
The evidence to date suggests that TVT gives better outcomes for ISD and severe SUI. The long-term TVT outcome studies have reported that the procedure remains effective (77% success rates), even after 10 years.[47, 48]
Supra pubic arch slings
In this technique, the needles are passed from a suprapubic incision into the vagina though the retropubic route (above-downwards). The subjective cure rate was lower than that of the TVT in the short-term (76.5% vs 87.5%). Complications, such as vaginal erosion and return to theater for loosening of tape, were higher in this group.
Single incision mini slings
SIMS were first introduced in 2006, and gained popularity amongst surgeons despite limited supportive evidence with regards to their efficacy. The principle underlying this technique is to insert a shorter sling through a single vaginal incision providing suburethral support while avoiding the groin and a retropubic approach to reduce morbidity. The TVT secur is an example of a midurethral sling that was developed in an attempt to reduce the risk of complications associated with TVT and TOT. The sling can be inserted in a U-shaped position where the prolene mesh is fixed in a U-shape into the connective tissue of the urogenital diaphragm. Alternatively, the mesh can form a hammock position, H-shaped, in the obturator internus muscle. A 1-year follow-up study comparing both approaches showed that both approaches had comparable cure rates. Objective cure rates were 87.5% for the U-type method and 80.1% for the H-type method (P = 0.091). However, quality of life and patient satisfaction assessment favored the U-shaped method. The low success rates with SIMS had been previously noted in observational studies, with reported success rates of 40% at a mean follow-up time of 30.2 months and 10% at 2 years.[51, 52] A meta-analysis analyzing the effectiveness of SIMS reported lower objective cure rates and higher reoperation rates with SIMS.
Periurethral bulking agents
Numerous bulking agents have been used in the treatment of SUI. The concept of this procedure originates from the idea that periurethral injection of a bulking agent under the submucosa solidifying and forming artificial cushions will result in increased resistance to urine flow and restoration of continence. There have been concerns regarding the long-term safety associated with the type of bulking agent injected. A recent Cochrane review of urethral bulking agents concluded that there is insufficient evidence to show any benefit from the use of agents injected into the midurethral or bladder neck regions in women who are fit for a surgical procedure. Periurethral bulking agents could have a role in patients precluded from surgery, though one must be cautious with regards to the long-term safety. The initial results from the investigation into the safety and efficacy of urethral injections of autologous total nucleated cells along with platelets seem to be promising. Although stem cell therapy holds much promise for SUI, the clinical applications in patients have been slow to materialize.
Artificial urinary sphincter
AUS were developed to treat patients with clinical and urodynamically defined ISD that significantly affected the quality of life of the patient. These are mechanical devices that consist of a pump, cuff and reservoir, which is filled with water and compresses the urethra. The success rate of a successful implantation reduces with the number of prior surgical procedures as a result of cuff erosion. Current recommendations suggests that it should be considered after one but not more than two surgical revisions for SUI. They should only be inserted in tertiary centres of excellence that have experience with them. A retropubic or transvaginal route can be used to insert the AUS. The latter approach is associated with greater morbidity and infections rates leading the retropubic approach to be the preferred choice. Complications associated with AUS include cuff and pump erosion. They are also subject to mechanical failure. A review of studies with patients who had AUS, demonstrated variable findings. Improvements in continence rates vary from 33–100% whilst erosion was seen in up to 67% in one study with mechanical complications occurring in up to 29% of patients. The results from studies in AUS are difficult to interpret meaningfully due to the low numbers of patients that are recruited. Laparoscopic approaches to insert AUS have been developed.
Menopause, higher education, no previous urinary incontinence surgery and lower incontinence frequency were found to be predictors of success and satisfaction with non-surgical therapy for SUI. This level 2 evidence could help better align provider and patient expectations with non-surgical treatment outcomes.
The TVT technique has consolidated its position as the gold standard surgical treatment for SUI. As MUS can be carried out as a day case procedure without compromising clinical efficacy, they also facilitate the throughput of patients while maintaining patient satisfaction. The NICE recommends that the surgeon should carry out at least 20 procedures per year to maintain competence, and should use only type 1 monofilament polypropylene sling. Although TVT and TOT are of comparable efficacy, at least over the short- and medium-term (Fig. 2), the complications associated with these procedures are different. Patients should be appropriately counselled and informed of the advantages and risks associated with the procedures. Long-term safety and efficacy data are awaited on the TOT approach.
If clinical practice is to be guided informatively, future work in this field will need to compare any emerging techniques against the acknowledged gold standards using universally defined short- and long-term patient reported outcome measures that are uniformly defined across studies.
Dr S Rachaneni for reading and suggesting revision to the manuscript.