This register-based study of 626 operations for isolated, recurring rectocele shows that the benefits of using non-absorbable mesh reinforcement may outweigh the risks and indicates that permanent surgical mesh may be a viable treatment option for this particular patient group, if confirmed by longer term studies. In this article, we provide information from real-life routine health care settings that might be helpful both to the surgeon and for the patient in the decision regarding which process will be most beneficial for the patient.
Surgical mesh has been used in POP surgery for nearly a decade, but there is still no clear international consensus on how, when and with which type of prolapse it might be advantageous to use such implants. The surgeon must make a risk assessment for each individual case, and the patient must be able to make a personal, informed decision as to whether she wants an augmentation using an implant. Essential in this process is a clear, realistic description of both the desired and unwanted effects of the planned surgery.
The evaluations of mesh use in prolapse surgery are often unstratified, where the individual vaginal compartments are either pooled or unspecified, or assumed to be of equal impact, and this produces ambiguous results regarding site-specific evaluations of impact [3, 14]. From continuous monitoring of GynOp register items, we know that the posterior vaginal wall is the second most common site of POP. In Sweden, two-thirds of the total number of synthetic mesh operations in POP are performed on recurrent patients, and this group is therefore of particular interest.
As in previous articles published by us in collaboration with the GynOp register [6,7,8], our material consisted of a very specific patient subgroup within POP. This was done to achieve a compartment-specific, clinically applicable evaluation of mesh reinforcement in the main individual patient groups within the POP group. Even though our work encompasses a highly specific patient group (patients operated solely for recurring rectocele), the sample size is large because of the extensive material provided by the register, making it possible to analyse subgroups without compromising the precision of the results.
The study has varying sample sizes for different parameters. This variation is due not to missing patients, but to some patients not being eligible to answer the questions. For example, in Table 2 only patients who had previously reported a complication within 8 weeks received the question of whether these complications had led to hospitalisation. Similarly, there are more 8-week results available than 1-year results, simply because not all the patients who answered the first questionnaire were eligible to answer the 1-year questionnaire at the date of data extraction from the register.
Some parameters had a high degree of missing information, such as the degree of prolapse and smoking status (Table 1), and both may influence severity and recurrence. However, none of these instances were such that statistical analysis was not feasible.
There was a difference between patient groups regarding both age and degree of prolapse. Both could affect the outcome of the operation and therefore represent possible confounding factors in our study. We measured the position of the anterior respectively posterior vaginal wall prolapse in relation to the hymen in cm for each group. Statistically significant differences can be seen between groups 2 and 3 (the second most and most severe prolapse groups). In relative terms there are 17% more native patients in group 2 and 14% more mesh patients in group 3.
This would potentially diminish cure rates for the mesh group; thus, our conclusion about mesh benefits may be underestimated.
The mean age difference between groups was 4.8 years. Whether or not this age difference will affect the outcome of the operation and patient satisfaction is unknown.
In the literature, concerns have been expressed that implants might increase urinary incontinence. In our material, we show that in a routine health care setting there was no difference in patient-reported de novo incontinence and that existing urinary incontinence was actually improved equally for both patient groups.
The only symptom specific to prolapse is the awareness of a vaginal bulge or protrusion , and this is regarded as a valid way of measuring the existence of prolapse [16,17,18,19]. Other more specific urogynaecological symptoms have been shown to have a very weak link with direct measures such as the Pelvic Organ Prolapse Quantification (POPQ) tool compared with the symptom of “bulging” . Therefore, we regard the patient-reported cure rate as the most important clinical outcome measurement.
Patient-reported cure rates have the inherent problem of not having been objectively verified by a physician.
De novo prolapse in a new compartment, therefore, would be reported as a failed operation even though it might be unrelated to the surgical procedure. This might overestimate the total amount of failure, but it would not influence the differences between groups. Additionally, as the patients’ self-reported lack of bulging symptoms and their wellbeing are the goal of the operation, it is our belief that the anatomical evaluation is secondary.
More patients who were treated with mesh reinforcement compared with patients undergoing classic posterior colporrhaphy were cured at 1 year post-operation, with an NNT of 9.7. In addition, mesh reinforcement was superior or equal to native tissue repair in all parameters except for the number of post-operative surgeon-reported complications within 1 year. The number needed to harm (NNH) for any type of surgeon-reported complication was 8.5. This, if analysed in more practical terms, means that, for every 100 implants used on this particular patient group instead of native tissue repair, 10.3 additional patients will be cured, but simultaneously an additional 11.7 cases of surgeon-reported complications will occur. We reported only “minor surgical complications” because no major post-operative surgical problems occurred more frequently in either of the two homogeneous groups, and overall such major complications, including mesh erosions, were rare.
The strengths of this study are the large sample size, the fact that it mirrors results from “real life” and that it shows effectiveness rather than efficacy. The high rate of inclusion in GynOp means that the yearly registration of operations in GynOp represents the total number of operations performed in Sweden. Samples from GynOp are therefore complete national materials. The patient participation rate was very high for both the 2-month and the 1-year follow-up questionnaires (95% and 85%, respectively). This high inclusion rate has been attributed to the ubiquitous personal Scandinavian social security number and universal public health care coupled with a high degree of trust in the public authorities.
The main limitation of this study is the possibility of bias. While selection bias is likely to be a minor problem, as suggested above, information bias and confounding might still exist. Our mesh group had a greater degree of prolapse compared with the colporrhaphy group, but this selection bias probably did not affect the outcomes in favour of the mesh group. Some information or recall bias is likely because data are aggregated from patient questionnaires. In the register questionnaire, we asked the patients for the number of days they had taken painkillers at home. This parameter may be biased by different instructions from different clinics and may reflect clinical routines more than actual patient pain.
Further research in the form of a randomised trial would be needed to confirm with certainty any causality found in this cohort study. However, as this specific patient group encompass roughly 1.2% of all Swedish prolapse operations, this would require a randomisation of every single eligible Swedish patient for at least 5 years to get more than 150 patients per group (and, therefore, sufficient analytical power). A trial of this magnitude would be nonsensical, partly because of the hugely complicated process and partly because of the very small group of patients who would gain from the results. This probably also explains the small number of publications on compartment-specific surgery  and the almost complete lack of literature regarding recurrent rectocele operations alone.
Complication registration within the database is not implant-specific, but is designed to cover all types of expected surgical complications. Therefore, we cannot distinguish between complications characteristic of implants (e.g. bleeding due to mesh erosions) and general surgical complications (e.g. bleeding from the vaginal suture line). Similarly, regarding our registration of patient-reported complications, the severity of the reported complication is not graded. The criterion for the event of a “patient-reported complication” is that the event led to further unscheduled contact with the health care provider.
In our study, a bias is possible if clinical factors influence the decision whether or not to use mesh. Recently published data by GynOp show that the clinical factors such as age, BMI, etc., have no influence on the decision whether or not to use mesh in daily practice and that the clinical practice based on these clinical factors varies widely throughout the country. An abiding bias is therefore unlikely in our opinion .
Mesh types are not all alike and, therefore, as we utilise all kinds of non-resorbable polypropylene mesh, the subtle differences between brands would be overlooked. However, there is no difference in the general method of application of these mesh types or regarding the extent of the operation between brands, and all meshes in this analysis were made solely from polypropylene, generalising the results.
This is the fourth study based on GynOp that analyses operative outcome following the most common types of POP with or without mesh in the anterior or posterior compartments. In the three previous, methodologically similar articles, mesh had a superior 1-year cure rate but other disadvantages and drawbacks. In the present study, our overall conclusion for recurrent rectocele is that mesh implants are more beneficial than posterior colporrhaphy. In primary posterior vaginal wall repair, and also in both primary and recurrent anterior vaginal wall repair, the overall circumstances regarding the advantages of mesh use are more complex. A similar complex picture of the benefits of mesh augmentation can be found in a recently published randomised controlled trial .