Which sling for which SUI patient?
Stress urinary incontinence is often responsive to placement of a retropubic or transobturator midurethral sling. Here’s how to individualize your choice of sling.
IN THIS ARTICLE
Watch 3 video clips illustrating midurethral sling procedures
- Placement of TVT-O transobturator tape
- Monarc transobturator procedure
- TVT Exact retropubic sling operation
These videos were selected by Mark D. Walters, MD, and presented courtesy of the International Academy of Pelvic Surgery (IAPS).
Only 15 years ago, when surgery was recommended for patients who had bothersome stress urinary incontinence (SUI), they were offered operations such as suburethral (Kelly) plication, needle urethropexy, open or laparoscopic Burch procedure, and pubovaginal fascial sling procedure. Today, virtually all of these operations have been replaced in general practice by retropubic or transobturator (TOT) midurethral synthetic slings.
Although Burch colposuspension and the pubovaginal fascial sling procedure are effective for both primary and recurrent SUI, they are more invasive than midurethral slings, cause more voiding dysfunction, and have significantly longer recovery times, making them less attractive for most primary and recurrent cases of SUI.
The evolution of SUI surgeries has shifted so far toward midurethral slings that Burch colposuspension and the pubovaginal sling procedure are rarely performed or taught in obstetrics and gynecology or urology residency programs; these procedures are now mostly done in fellowship programs by specialists in female pelvic medicine and reconstructive surgery.
In this article, we describe how an ObGyn generalist can approach the surgical treatment of women who have either primary or recurrent SUI. Using evidence-based principles, when available, we also discuss how different clinical characteristics—as well as the characteristics of the available slings—affect the suitability of the sling for individual patients.
One caveat: This article assumes that the surgeon knows how to, and is able to, perform retropubic and TOT sling procedures equally well. However, when this is not the case, the surgeon should perform the sling procedure that she or he does best, assuming that it is appropriate for that particular patient.
Almost all surgical procedures for stress urinary incontinence performed today involve placement of a retropubic or transobturator midurethral synthetic sling.
Illustration: Craig Zuckerman for OBG Management
CASE: SUI and Stage II anterior vaginal prolapse
A healthy 45-year-old G2P2 woman complains of a 5-year history of worsening SUI symptoms, mostly occurring during activities such as coughing, laughing, and running. The incontinence has become so severe that she requires several pads daily. She is able to void without difficulty or pain, and her bowel movements are normal. She has regular menses, has had a tubal ligation, and is sexually active.
She reports that she has been performing daily Kegel pelvic muscle exercises, without improvement.
On physical examination, she is found to have Stage II anterior vaginal prolapse and urethral hypermobility, with normal uterine and posterior vaginal support. The uterus and ovaries are of normal size.
A full bladder stress test in the office reveals immediate loss of urine from the urethra upon coughing in a semi-sitting position. She voids 325 mL after the examination and has a post-void residual urine volume, as measured by ultrasonography (US), of 25 mL. Urinalysis is negative.
When discussing her goals, the patient expresses a desire for a cure of her urinary incontinence, if possible.
What further testing and treatment options do you offer to her?
If you and the patient agree that surgery is warranted, which procedure do you recommend?
Women who have bothersome urine loss during activities such as exercise, coughing, or laughing should undergo a history, physical examination, and urinalysis. During the pelvic examination, it is important to assess pelvic organ support defects, especially those involving the anterior vagina and urethra. Also note levator ani muscle contraction and strength. In addition, you can use this time to discuss whether the patient is doing, or has done, pelvic muscle (Kegel) exercises; teach the exercises, if necessary; and encourage her to do them in the future.
If the patient has no urinary infection, has performed Kegel exercises without further benefit, and wishes to consider surgical treatment, basic assessment of lower urinary function is indicated. Basic office urodynamic testing includes:
- a measured void
- measurement of post-void residual volume (by catheter or US)
- assessment of bladder sensation and capacity
- provocation for overactive bladder
- a full-bladder cough stress test (a positive test is direct observation of urethral loss of urine upon coughing).
Patients who have a complex history or mixed symptoms, previous failed surgery, or other characteristics that suggest a diagnosis other than simple SUI should undergo formal electronic urodynamic testing.1
Patient selection criteria
Primary sling surgery is an option for patients who have:
- no urinary infection
- normal voiding and bladder-filling function
- urethral hypermobility on examination
- SUI on a cough-stress test
- failure to improve sufficiently with pelvic muscle exercises.
Suburethral slings were initially developed as a treatment for recurrent, urodynamically confirmed SUI, particularly SUI caused by intrinsic sphincter deficiency (ISD). Pubovaginal slings, usually consisting of autologous fascia, were placed at the bladder neck to both support and slightly compress the proximal urethra. Compared with synthetic slings, fascial slings are effective but take longer to place and have a higher rate of surgical morbidity and more postoperative voiding dysfunction. They are now mostly indicated for complex recurrent SUI, usually managed by specialists in female pelvic medicine and reconstructive surgery.
Current slings are lightweight polypropylene mesh
Most slings today are tension-free midurethral slings consisting of synthetic, large-pore polypropylene mesh; they are sold in kits available from several different companies. Sling procedures can also be performed using hand-cut polypropylene mesh and a reusable needle passer.
These slings are placed at the midurethra and work by mechanical kinking or folding of the urethra over the sling, with an increase in intra-abdominal pressure. Ideally, the midurethral sling will not compress the urethra at rest and have no effect on the normal voiding mechanism.
Three main techniques are used to place synthetic midurethral slings:
- the retropubic approach
- the TOT approach
- variations of single-incision “mini-sling” procedures.
Early studies of mini-slings showed few complications but lower effectiveness, compared with retropubic and TOT midurethral slings, according to short-term follow-up data.2-4 A mini-sling might be an option for some patients in whom surgical complications must be kept to a minimum; otherwise, they will not be discussed further.
Retropubic midurethral slings
The tension-free vaginal tape (TVT) procedure described by Petros and Ulmsten was the first synthetic midurethral sling.5 This ambulatory procedure aims to restore the pubourethral ligament and suburethral vaginal hammock by using specially designed needles attached to synthetic sling material.
The synthetic sling consists of polypropylene, approximately 1 cm wide and 40 cm long. The sling material is attached to two stainless steel needles that are passed from a vaginal incision made at the level of the midurethra, through the retropubic space, and exiting at a previously created mark or stab incision in the suprapubic area (FIGURE 1).
Variations of the retropubic midurethral sling have been developed, with sling passers going from the vagina upward (“bottom to top”) and also from the suprapubic area downward (“top to bottom”). A recent Cochrane review reported that the bottom-to-top variation is slightly more effective.6
FIGURE 1 Retropubic sling
Placement of the tension-free vaginal tape trocar into the retropubic space.
Illustration: Craig Zuckerman for OBG Management
Transobturator midurethral slings
The TOT sling has become one of the most popular and effective surgical treatments for female SUI worldwide (Video 1 and Video 2). It is a relatively rapid and low-risk surgery that is comparable to other surgical options in effectiveness while avoiding an abdominal incision and the passage of a needle or trocar through the space of Retzius.
The TOT sling lies flatter under the urethra and carries a lower risk of urethral obstruction, urinary retention, and subsequent need for sling release, compared with retropubic slings.7-9 Compared with the retropubic TVT, the TOT sling produces similar rates of cure, with fewer bladder perforations and less postoperative irritative voiding symptoms.6,10-12 It nearly eliminates the rare but catastrophic risk of bowel or major vessel perforation. The trade-off is that patients experience more complications referable to the groin (pain and leg weakness or numbness) with the TOT approach.9,13
All TOT slings on the market consist of a large-pore, lightweight, polypropylene mesh strip, usually covered with a plastic sheath. Various devices are used to place the sling, but most of them involve a helical trocar that curves around the ischiopubic ramus, passing through the inner thigh and obturator membrane to a space created in the ipsilateral peri-urethral tissues.
TOT slings can be placed outside-to-inside or inside-to-outside (FIGURE 2), and the indications, effectiveness, and frequency of complications seem to be similar between these two approaches.12 One study found a higher frequency of new sexual dysfunction (tender, palpable sling; penile pain in male partner) in women after the “outside-in” approach,14 but this clinical issue has not been observed in all studies.15,16
FIGURE 2 TOT sling variations
Placement of the transobturator (TOT) sling helical trocar using the (A) “outside-in” variation and (B) “inside-out” variation.
Illustration: Craig Zuckerman for OBG Management
Reprinted with permission, Cleveland Clinic Center for Medical Art & Photography
© 2005-2012. All Rights Reserved.
Success rates are similar for retropubic and TOT slings
Despite differences in technique and brand of mesh used, treatment success rates for uncomplicated primary SUI are similar for the retropubic (Video 3) and TOT tension-free slings.6-8,10-12,17 The percentage of patients treated successfully depends on the definition used, ranging from a high of 96% to a low of 60%. When the definition of success is restricted to stress incontinence symptoms, especially over a short period of time, the reported effectiveness is high.
In contrast, when the definition of success includes incontinence of any type, the reported effectiveness is lower. For example, in the study that reported 60% effectiveness, success was defined as no incontinence symptoms of any type, a negative cough stress test, and no retreatment for stress incontinence or postoperative urinary retention.11
Retropubic slings, especially TVT, may be somewhat more effective for ISD,18-20 although this conclusion must be tempered by the small number of studies addressing the issue and differences in the diagnosis of ISD.21
Some studies have reported good success in treating mixed urinary incontinence with the retropubic and TOT slings,2,8 although other studies have reported that the initial benefit for urgency or urge incontinence is not sustained over time, compared with the benefit for stress incontinence.22 It is important to counsel patients before surgery that improvement in stress incontinence symptoms and general satisfaction is highly likely, but perfect bladder function is not.
Serious complications are uncommon
Complications are common after both retropubic and TOT slings, although serious complications are uncommon. Cystitis and temporary voiding difficulties are the most common problems after a sling procedure. If the patient is unable to void on the day of surgery, it is reasonable to discharge her with a Foley catheter in place for a few days or teach her to perform intermittent self-catheterization at home. In most cases, normal voiding will resume within a few days. Cystitis is at least partially related to the surgery itself and the duration of postoperative catheterization.
The frequency of some complications differs between the retropubic and TOT approaches to midurethral slings. For example, some literature suggests that irritative voiding symptoms such as urgency or voiding difficulty are somewhat less common after TOT slings, compared with retropubic slings. However, symptoms referable to the groin (pain and leg weakness or numbness) occur more commonly with the TOT approach.6
After placement of a TOT sling, 10% to 15% of women experience temporary inner thigh or groin pain or leg weakness and are usually managed conservatively with nonsteroidal anti-inflammatory drugs and physical therapy. Long-term or severe complications related to TOT sling passage are rare.