Mike: Hello, I'm Mike Clarke, podcast editor for the Cochrane Library. Cochrane Incontinence has produced more than 40 Cochrane reviews of interventions that might help people suffering from incontinence. In this podcast, Roses Parker, Cochrane's Commissioning Editor talks with lead author of the review Emily Carter, a senior clinician and researcher in urogynaecology in the Manchester Foundation Trust in the UK about the October 2023 update of the review for single-incision slings, a type of surgery for stress urinary incontinence.

Roses: Hello Emily. First of all, can you tell us about stress urinary incontinence in women and how it's usually treated?

Emily: Hello Roses. Stress urinary incontinence is leaking of urine when women cough, sneeze or exercise and affects one in every two women. It's caused by weakness in the pelvic floor muscles, and the initial treatment is usually strengthening exercises for these muscles, but about 10% of women require surgery to support the bladder neck and urethra, which is the urine drainage pipe from the bladder.
One type of surgery uses single-incision slings, which are a type of mesh. They were designed to be minimally-invasive and nine different types of single-incision sling devices have been marketed and all were eligible for this review.

Roses: Thanks. Can you tell us a little more about the various types of sling?

Emily: There are three categories. Autologous fascial slings are made from the woman's own body tissue. Standard mid-urethral slings are made from relatively long strips of polypropylene plastic mesh tape which are anchored in surrounding tissue and include retropubic slings and trans-obturator slings. Lastly, single-incision slings are made from relatively short strips of mesh tape, placed through a single cut inside the vagina.
For all three types, connective tissue grows through the holes in the mesh to anchor it in position. But, in recent years, mesh slings have come under widespread public scrutiny and some have been withdrawn from the market.

Roses: Following on from that, why is it important to have a review of the effects of this treatment?

Emily: Incontinence is very common and many women require surgery. Mesh tapes were extremely popular a few years ago but there are currently concerns about their use. For example, in some countries, such as the, UK these operations are no longer offered routinely, but they are still used in many parts of the world. Therefore, women who are having, or have had these operations need reliable information about the effects and this information should also be used to influence clinical guidance and practice worldwide.

Roses: So, what did you want to assess in the review and how much evidence did you find?

Emily: Our aim was to compare single-incision slings to any other operation for stress urinary incontinence for curing and improving incontinence, risk of painful sex, risk of mesh erosion, urinary retention, risk of infection, need for repeat surgery and quality of life. The single-incision slings have been well researched in randomised trials, and in this updated review we now include results from 62 studies of more than 8000 women.
However, 16 of these studies tested TVT-Secur, a single-incision sling withdrawn from the market in 2013 because it was not found to be effective and, so, we did not include data for it in our main conclusions. There were also no studies comparing single-incision slings to conservative treatment, pelvic floor training or bladder lifting surgery. And, even where there were eligible studies, many of these did not provide evidence for long-term outcomes, or for comparisons we specified as key for this review. However, we do have data on some of the comparisons.

Roses: Let's start with single-incision slings versus autologous (native tissue) slings. What did you find?

Emily: One study compared single-incision slings to autologous slings but it did not report on cure or improvement of incontinence. There was little difference between the operations for painful sex and mesh erosions, but we could not be certain of the results and the study did not report on other outcomes.

Roses: How about single-incision slings versus retropubic slings?

Emily: Ten studies made this comparison, finding little to no difference for patient-reported cure or improvement and there was no information on long-term pain or painful sex. We were unsure of the results for other outcomes: mesh erosion, urinary retention, repeat surgery and quality of life.

Roses: Lastly, how do single-incision slings compare to transobturator slings?

Emily: This was the largest set of studies in the review, with 51 trials. We have high confidence that women were just as likely to be cured or improved of their incontinence with single-incision slings as with trans-obturator slings. In addition, women with single-incision slings may have a similar number of mesh erosions and the same risk of urinary retention but report less pain over all time periods studied. We were uncertain about the risk of painful sex and women may have a slightly poorer quality of life, but we were not certain of this result. It also wasn't clear whether women require more repeat surgical procedures with single-incision slings or with obturator slings.

Roses: You mentioned that this is an updated review. How do the findings compare to its previous version and other reviews?

Emily: The previous version of this review, for which the searches were done in 2012, and older reviews analysed TVT-Secur along with other single-incision slings, and found that overall single-incision slings were inferior to other mid-urethral slings in terms of cure of incontinence. However, we have now shown that when the TVT-Secur group is removed from the analysis, the other single-incision slings are clearly as effective at treating incontinence as other mid-urethral slings. This agrees with other recent reviews on this topic, including when individual single-incision slings are compared to each other.

Roses: So, to finish, what would you say are the key messages from the current review and how can people get hold of it?

Emily: I'd say that single-incision slings are as likely as other mid-urethral slings to cure or improve incontinence and may be associated with less pain but higher reoperation rates. However, the evidence is largely limited to less than 2 years follow up, making it is difficult to assess long term outcomes such as pain, mesh erosion and long-term success. To get the review, people should go to Cochrane Library dot com and type 'single-incision sling' in the search box.