Chapter 6: Reviewing the evidence on mesh implantation for the treatment of stress urinary incontinence and pelvic organ prolapse in women: clinical nuances of interpretation
What's new in this Chapter?
In our interim report, chapter 6 provided additional information and clinical interpretation on several pieces of evidence not included in the main literature review in chapter 5. In this final report these, and other more recent publications have been incorporated into chapter 5. This chapter is now used to explore some of the nuances of clinical interpretation of the evidence presented earlier. It is hoped that readers might find this helpful in understanding how we have reached our conclusions and recommendations; clinicians may find it of value during their counselling of patients considering surgical treatment for SUI or POP.
Although many non-surgical and surgical options for the management of SUI and POP are included in chapter 2, and many others have been advocated, we have restricted our consideration here to those used most commonly in Scotland (as in chapter 4) and covered in the literature review in chapter 5.
6.1 Outcome measures
The outcome measures used in the available trials and systematic reviews are described in chapter 5. These were considered under a number of key outcome areas including the effectiveness of the procedure(s), safety issues, patient-focussed outcomes (positive or negative), surgical capacity and competency issues. It has been traditional in urogynaecology/functional urology to consider so-called 'objective' outcome measures, e.g. the finding (or absence) of urodynamically-proven SUI to have greater credibility than so-called 'subjective' outcomes, e.g. patient reported symptoms. This position is, however, changing, and patient-reported measures are now considered the more meaningful trial outcomes.
In the management of individual patients, it is important that their own goals and expectations from treatment are defined as part of the counselling process; if these are not linked to known surgical outcomes, patient satisfaction from treatment will inevitably be compromised.
6.2 No treatment and non-surgical options
It is not only inherent in the recent Supreme Court ruling,  but also fundamental to shared decision making, and patient-centred care as described in 'Realistic Medicine',  that all reasonable options should be discussed with a patient requesting treatment for any condition. Although our report focusses on the place of mesh implants as a component of the surgical treatment of SUI and POP, we feel it is important to emphasise to all patients presenting with these conditions, that they do not necessarily need to undergo surgery. The reassurance that they could live with their symptoms without any treatment may in itself be a huge relief for many women. Non-surgical options may provide satisfactory symptom control for the majority in the short to medium term ( e.g. pelvic floor muscle exercise ( PFME) for SUI or POP), or indeed in the long-term ( e.g. vaginal pessaries for POP). In either case these options may mean that they could avoid surgery altogether, or at least defer intervention until a more suitable time for them.
6.3 Safety issues
None of the previously published safety reviews has recommended the withdrawal of mesh products in current use in surgery for SUI or POP, and we have found no additional evidence to support such an approach. Nevertheless, we do recognise that there can be adverse outcomes, some serious, albeit that these occur in small numbers of patients.
Adverse events are more prevalent following the use of synthetic mesh in the treatment of POP than SUI. In POP adverse events are more common following vaginal than abdominal insertion of mesh, and in SUI serious adverse events are more common following transobturator than retropubic tape insertion.
There is a higher risk of bladder injury from retropubic mesh tape than open colposuspension (and transobturator mesh tape), although it should be noted that bladder injury with mesh tape is diagnosed intra-operatively in almost all cases, as cystoscopy is routinely employed. It is believed that if the tape is replaced in the correct position, no long-term problems are expected. In contrast, bladder injury with colposuspension may require formal repair and several days' additional postoperative catheterisation.
6.4 Synthetic tape or mesh removal
Whilst it may seem counter-intuitive to consider the removal of a device intended for permanent implantation, explantation of both mesh tapes used in SUI surgery, and synthetic meshes used in POP surgery, may have to be considered on rare occasions. It is the view of the clinicians on the group that retropubic mesh tapes can be removed in their entirety regardless of duration of implantation, although this would usually require an open or laparoscopic abdomino-perineal approach. The same could be said of 'simple' mesh implants for POP, via a vaginal approach. Complete removal of a transobturator mesh tape (or POP mesh kit) can be difficult. These are easier to remove within a few weeks of implantation, but with appropriate skill and experience, a surgeon may be able to remove an implant at any time. The majority of requests for removal come some years after surgery, and the longer the implant is in place, the more difficult it is to remove completely. Since the link between mesh tape (for SUI) or mesh (for POP) insertion and the development of symptoms remains uncertain, and it is never possible to say that removal of a mesh tape or mesh will resolve symptoms, a stage is inevitably reached where the risks of removing the mesh exceed the possible benefit.
6.5 Efficacy issues
6.5.1 Efficacy of surgery for SUI
Although our review includes analysis of data on anterior colporrhaphy, bladder neck needle suspension, and laparoscopic colposuspension, in common with NICE guidance, we do not feel that the first two of these should be offered in the treatment of SUI. Laparoscopic colposuspension should not be offered routinely, and should only be considered where an experienced laparoscopic surgeon is working in an MDT with expertise in the assessment and treatment of UI.
Mesh tape procedures are as effective as traditional surgical approaches ( i.e. colposuspension and traditional pubo-vaginal sling procedures) and have the benefit of shorter operative time, less anaesthetic requirement, less requirement for catheterisation, shorter hospital stay, reduced NHS costs and more rapid return to normal activities of daily living and work. There is also a lower risk of subsequent prolapse and need for prolapse surgery.
Although in the short-term, efficacy of mesh tapes inserted by the retropubic and transobturator routes is not significantly different, beyond 12 months there is a substantially greater need for repeat SUI surgery following the transobturator approach; the emerging evidence on single-incision mesh tapes also suggests even greater need for repeat SUI surgery than following the transobturator approach.
Although urethral injection therapy has been advocated as a minimally invasive option in the treatment of SUI, and systemic review suggests a better short-term safety profile than other interventions, the very much higher rate of re-admission for complications or re-operation for SUI in the longer term is a genuine concern.
In light of the totality of these findings, the members of the IR who perform surgery for SUI are of the view that:
- the retropubic mesh tape is a valid option to be offered routinely to women considering surgical treatment for SUI;
- colposuspension and autologous fascial pubo-vaginal sling are both appropriate alternatives for women who wish to avoid the use of a permanent implant, provided they accept the increased associated short-term morbidities and longer recovery, and increased long-term risk of prolapse following colposuspension;
- women may wish to consider urethral injection therapy; they should be made aware that the efficacy is less than with other interventions, and decreases over time; hence the risk of re-admission for complications or re-operation for SUI is very much higher; and
- small numbers of colposuspension and autologous fascial pubo-vaginal sling procedures have been undertaken in Scotland in recent years (see chapter 4); if a procedure cannot be provided locally, by appropriately skilled and experienced staff, the option of referral to alternative units should be discussed with the patient.
6.5.2 Efficacy of surgery for POP
Whilst many of the data relating to surgery for POP are inadequate to guide practice, we are persuaded by the latest Cochrane review and the recently published outcomes from the PROSPECT study. The former, whilst finding lower rates of prolapse signs or symptoms following mesh implantation at repair surgery, found higher rates of bladder injury and new SUI, and a greater requirement for repeat surgery for recurrence or complications (as a composite outcome), compared to native tissue repair. The authors concluded that transvaginal mesh has limited utility in primary surgery; whilst they speculated as to its place in women at high risk of recurrence, they found no evidence to support its use in this context either.
The PROSPECT study found that augmentation of a vaginal repair with either synthetic mesh or biological graft material did not improve women's outcomes in terms of effectiveness, quality of life, adverse eﬀects, or any other outcome in the short-term, but more than one in ten women had a mesh complication. Although, as the PROSPECT authors pointed out, addition of the PROSPECT data to the Cochrane review does favour mesh both in terms of awareness of prolapse and anatomical recurrence; nevertheless, we agree that a single large trial that is free from risk of bias is likely to be more powerful and reliable for the speciﬁc population included than a meta-analysis of many smaller trials.
Hence, it is the view of the members of the IR who perform surgery for POP that:
- Vaginal wall repair using native tissue (anterior and posterior colporrhaphy) should be the procedure of choice for women seeking surgery for POP.
- The use of polypropylene mesh or biological graft should not be offered routinely but may be considered in complex conditions - only after discussion at an appropriately constituted MDT.
Email: David Bishop