Mesh erosions are thought to be caused by some degree of bacterial colonization/infection within the mesh [9
]. The higher erosion rates of erosions found in this study are consistent with the properties of the Mersilene®
is a permanent macroporous mesh with multifilament microporous components. The pore size of Mersilene®
mesh is smaller than the typical diameter of a macrophage (10 µm) but larger than the diameter of bacterial cells (typically less than 1 µm). For this reason, synthetic materials with woven microporous multifilament structures have been criticized as potential bacterial havens, allowing bacteria to colonize where macrophages cannot reach. Indeed, previous studies comparing different types of mesh used in incontinence surgery have described higher rates of erosion with microporous materials (3.1% to 19.5%) than macroporous monofilament meshes such as polypropylene (0.9%) [10
]. Furthermore, we found unexpectedly high rates of concurrent cellulitis and abscess formation with Mersilene®
mesh in our study.
Only a few studies have documented the erosion rate attributable to Mersilene®
mesh alone. In abdominal sacrocolpopexies, Mersilene®
erosions have been reported in the range of 2.5% to 4% [12
]. Using it in an antiincontinence procedure, Young et al. reported a 1.8% erosion rate 1 year following the procedure [14
]. Our study yielded similar results at 1 year with 2.5% of women presenting with a mesh erosion. Although we found that the median time to reoperation was 2 years, our study did include 12 women who had undergone Mersilene®
sling placement 4–10 years prior to reoperation and one woman who had undergone sling surgery 20 years prior. Our longer study time span demonstrates that erosions from permanent materials can be quite delayed and that diligence is needed in the follow-up care for women after any surgery placing permanent material, as complications from the mesh can present so much later than the index surgery.
Previous reports have suggested that conservative management of sling erosions is successful in the early postoperative period [15
]. Our study did not investigate the long-term success of conservative management of sling erosions, but rather investigated those which were managed in the operating room. Our study did include 14 women who had undergone repeat procedures, which suggests that surgical revision, i.e., not removal, is likely to be of benefit only when the sling is not colonized with vaginal or anaerobic flora. We theorize that conservative management of sling erosion found more than 6 months postoperatively may ultimately lead to chronic infection, erosion, or sinus tract formation from the remaining colonized mesh. This emphasizes the importance of seeing women early and frequently in the postoperative period following any mesh placement to detect erosion.
Our study is limited by the retrospective design. We assumed that all erosions of Mersilene®
mesh presented back to our institution where the revision/removal surgery was performed. The state of Rhode Island is home to 11 hospitals providing gynecology services; Women and Infants’ Hospital performs 61.2% of all inpatient gynecological procedures [16
]. Therefore, it is possible that some patients with Mersilene®
sling complications/erosions sought care at a different hospital. This would underestimate our reported erosion rate of 8%.
Surgical data from the index case of the initial mesh placement and from those women with Mersilene®
mesh whom did not present with erosions were not collected. Therefore, risk factors for mesh erosion cannot be inferred from our study. For example, the prevalence of tobacco use in the adult population of our state at the time of the study (19%) was similar to the rate reported by women with mesh erosions (18%), but tobacco use among the women without mesh erosion is not known [17
]. In addition, women at a tertiary care center may be more likely to undergo multiple surgical procedures at the time of initial mesh placement, which may increase a woman’s overall risk of mesh erosion.
This study however is strengthened by its review of a large number of Mersilene® mesh sling procedures over a 10-year period at an institution that performs a high number of gynecological surgeries and that many residents of the state of Rhode Island remain in the state and do have their gynecologic surgery at our institution, thus providing longer term follow-up.
The most common presenting symptoms of sling erosion were vaginal discharge and vaginal bleeding. Symptoms of vaginal discharge and bleeding should be presumed to be caused by mesh erosion in women with a prior history of any mesh placement until proven otherwise. Mesh erosion or exposure should be considered as a possible cause of chronic persistent vaginal discharge. Pelvic examinations must be very meticulous to detect erosions within the vaginal ruggae and sulci. Cystoscopy should be considered for women with irritative voiding symptoms and a history of mesh placement as these symptoms were present in women noted to have mesh within the bladder on cystoscopy.
The recent shift in the development of synthetic materials has favored a macroporous monofilament structure that allows tissue in-growth while also allowing macrophages to traverse its framework in search of residing bacteria. Thus, the use of Mersilene® mesh has fallen out of favor. However, providers need to maintain a high index of suspicion for mesh erosion in this group of women even many years beyond from their initial surgery, as we have shown that complications from Mersilene® mesh may present as far as 20 years after initial placement.