Mesh removal and ventral hernia repair with long-term absorbable mesh in case of mesh infection

Ventral hernia repair still induces a significant short- and long-term morbidity [1, 2]. One of the most feared complications after this operation is the infection of the mesh that often needs to be removed [3, 4]. Mesh infections after ventral hernia repair occur in 1 to 8% of patients [5, 6]. Mesh infections are more frequent after open repair (7–8%) [7, 8] than after minimally-invasive surgery (1–2%) [9, 10]. Several risk factors for mesh infection after hernia repair such as uncontrolled diabetes mellitus, obesity, active smoking, immunosuppressive medication including steroids, onlay (subcutaneous) mesh position, intraoperative bowel lesions, or postoperative surgical-site infections have been described [11, 12]. A postoperative surgical-site infection can contaminate the mesh depending on the location of the mesh (intraperitoneal, preperitoneal, retromuscular, or subcutaneous) and the depth of the infection [11]. After contamination, acute or chronic mesh infection can develop. Mesh infection is often polymicrobial, the most frequent pathogens being Staphylococcus aureus, Enterobacteriaceae, and anaerobic bacteria [13]. Once infection of the mesh occurs, it is often necessary to remove the mesh to definitely treat the infection [14]. Possibility of mesh salvage depends on various factors such as the type of involved bacteria, the timing of the mesh infection, and the type (long-term absorbable, synthetic or biological, pore size, material) and location of mesh that was used. In particular, polytetrafluoroethylene (PTFE) meshes have been shown to be more at risk of requiring explantation [11, 15]. Even though risk factors have been identified, the management of mesh infection currently remains controversial with no clear guidelines [5]. Some studies have shown that a large percentage of macroporous polypropylene infected meshes can be salvaged (up to 80%) when negative pressure wound therapy is used [4, 16], especially when located extraperitoneally, while other studies recommend mesh explantation for other mesh types or intraperitoneal location [17].

Recently, the use of long-term absorbable mesh has been shown to be potentially more resistant to infection than synthetic meshes, and to be safe when use in certain contaminated fields [18, 19].

For a couple of years now, in case of abdominal wall mesh removal due to infection, our management strategy was to use a long-term absorbable mesh to reinforce the abdominal wall. The long-term absorbable mesh is either put at the same time as mesh removal (single-stage management) or after a couple of days following subcutaneous vacuum-assisted (VAC) therapy during a second operation (two-stage procedure) [19, 20]. Using this strategy, it was hypothesized that antibiotherapy could only be for a short time window (therefore potentially decreasing the inherent risk of secondary effects and allergies), patients could have shorter length of stay (LoS), hospital costs, or less risk of developing chronic infection when treating an acute mesh infection.

The aim of the present study was to assess the short- and long-term outcomes after such a strategy (use of long-term absorbable mesh) for patients with infected ventral mesh requiring removal in an acute and chronic context.

A total of 29 patients were included in the study (13 from Strasbourg and 16 from Lyon): 14 acute infections and 15 chronic infections. Median age of the patient cohort was 71 years (IQR 54–73). Fifteen women and 14 men were included in the overall cohort. Median body mass index was 29 kg/m² (IQR 27–35). Before mesh infection, 7 patients presented a primary hernia (umbilical or epigastric hernias) and 22 patients had an incisional hernia. Among the 22 patients with incisional hernia, 9 patients had undergone a urological surgery, 8 a gastrointestinal surgery, and 5 a gynecological procedure.

This study assessing the use of a long-term absorbable mesh after removal of an infected mesh in acute and chronic conditions showed that postoperative complications occurred frequently but that the incidence rates of new mesh explantation and hernia recurrence were low.

The current study evaluated the outcomes of the use of a long-term absorbable poly-4-hydroxybutyrate mesh in contaminated fields (i.e., in case of previous infected mesh requiring removal). Some studies have suggested that long-term absorbable meshes such as poly-4-hydroxybutyrate mesh have theoretically better resistance in infected fields, making them ideal in case of removal of an infected synthetic mesh [18]. The theoretical and mechanistic advantages of using such a mesh are multiple. First, poly-4-hydroxybutyrate stimulates the expression of anti-microbial peptides in macrophages, therefore decreasing the risk of bacterial colonization and of surgical-site infection [27]. It should be noted that this property was found in vitro [27]. It is currently unclear if the same effect is found in vivo and if a contaminated field influences the biological response, which could explain the relatively high rate of surgical-site infections found after acute mesh infection (43%). Moreover, the monofilament biosynthetic scaffold with open pores facilitates rapid tissue incorporation, rendering the mesh potentially less sensitive to bacterial infection and better penetration of antibiotics in case of bacterial contamination. It has also been postulated to that lower immunogenicity induced by an increase anti-inflammatory response promoted by the poly-4-hydroxybutyrate compared to non absorbable synthetic meshes could play a positive role in an infectious context. In addition, as the mesh is resorbable (via hydrolysis occurring at a predictable and relatively stable rate), the risk of mesh infection occurring at a late stage could be decreased. Another possible advantage would be that if a hernia recurs as the infection increases the risk of recurrence, treatment options and specific planes are not compromised because the mesh would have been absorbed. Bueno-Lledo et al. published in 2021 a series of 30 patients with chronic mesh infection who underwent mesh removal and simultaneous implantation of poly-4-hydroxybutyrate mesh (single-stage management) [19]. They found a low hernia recurrence rate with only 3.3% of patients who presented a hernia recurrence within a median follow-up of 34.5 months. Of note, inguinal mesh infections were also included (n = 4), which was not the case in the present study focusing on ventral hernia. No hernia recurrence within 17-month follow-up was found in this study after chronic infection. In acute infection, 21% of patients presented a hernia recurrence, which remains within the range found in the literature for poly-4-hydroxybutyrate use in complex hernia repairs or in contaminated fields [28, 29]. Literature on recurrence rate after acute mesh infection remains scarce, as most data arise from chronic mesh infection, and most studies do not separate acute and chronic infections. In a retrospective review of the data from the Veterans Health Administration on mesh removal for infection within 5 years (no precisions on timing), Dipp Ramos et al. found that all patients who had only mesh removal without hernia repair developed a recurrence, while 49% of patients after subsequent hernia repair with mesh (biological mesh: 107/166 = 65%, synthetic mesh: 59/166 = 35%) presented a recurrence [3]. A systematic review and single-center study published in 2018 by Shubinets et al. showed that the recurrence rate in 43 patients with mesh explant for infection (no precision on timing) was 67% (2/3) if a two-stage procedure (reconstruction with mesh after VAC therapy) was performed and 35% (14/40) if a single-stage procedure (reconstruction with mesh at the same time as mesh removal) was done [30]. In the two-stage procedure (n = 3), 2 biological (Permacol© and SurgiMend©) and 1 synthetic (Ventralight ST©) meshes were used, while in the single-stage procedure (n = 40) 34 biological (15 XenMatrix©, 14 Permacol©, 4 SurgiMend©, and 1 Strattice©) and 1 synthetic (Vicryl©) meshes were used (5 unknown). In a retrospective cohort of patients (n = 47) with median time to infection of 27 months, Alimi et al. found that mesh removal with VAC therapy followed by hernia repair with biological mesh (Strattice©) yielded a 11% recurrence rate, but the mean follow-up was only 10 months [31]. It nevertheless remains unclear if a long-lasting repair with similar results as repair with synthetic mesh can be achieved with this strategy.

Postoperative complications within 90 days occurred in 64% (acute infection) and 60% (chronic infection) of the patients of the cohort, encompassing mainly minor complications and surgical-site occurrences. This high morbidity reflects the septic situation leading to increased perioperative risk and the risk of wound-related events. Moreover, patients with acute infection or chronic sepsis often are multimorbid and have a persisting inflammatory state, increasing the risk of complications. Prior series of patients undergoing mesh removal showed morbidity rates around 40–70% [19, 28, 29]. In the present studied cohort, all deviations from the ideal postoperative course even minor, such as electrolyte imbalance, asymptomatic seroma or transient urinary retention, were considered and classified as postoperative complications, which can induce some differences when comparing to other studies.

The benefits of the presented strategy that were found in the current study were the absence of chronic infection development in patients who were treated for an acute infection and a relatively low median LoS (between 7 and 10 days). This could potentially lead to cost reduction compared to the strategy of aiming to save the infected mesh, but no control group was included in this study and financial data were not available. Only 1 long-term absorbable mesh had to be explanted and was removed at the beginning of the implementation of the presented strategy. In their article including 30 patients, Bueno-Lledo et al. showed that no patient had to have their poly-4-hydroxybutyrate mesh removed with their one-stage strategy (mesh removal and simultaneous implantation of a long-term absorbable mesh) [19]. In a meta-analysis on ventral hernia repair in high-risk patients and contaminated fields, Morales-Conde et al. found that the pooled rate of synthetic mesh removal was 9% [29]. In this study, patients with modified VHWG classification grade 2 (clean-contaminated) and 3 (contaminated) were included. This represents an important heterogeneity between the studies to consider, whereas in the present study only patients with modified VHWG classification grade 3c were included (infected mesh). There are currently few data specifically assessing the outcomes of ventral hernia mesh repair in case of infected field, corresponding to grade 3c of the modified VHWG classification. The presented strategy also had disadvantages that need to be acknowledged. First, it can be seen as excessive in case where infected mesh could have been saved. Moreover, long-term data on the solidity of the repair and hernia recurrence risk remain unknown. The goal of this study was to present the outcomes of such a strategy and to show that it could be a management option in case of mesh infection. The presented strategy could be a complementary option to mesh salvage, interesting to have in our management armamentarium, especially in patients with high risk of mesh salvage impossibility (i.e., polytetrafluoroethylene mesh, intraperitoneal mesh, or enteroprosthetic fistula).

The present study has some limitations that need to be mentioned. First, this was a retrospective study with data retrieved from patient charts. This can induce some mistakes and a collection bias. Moreover, there were some missing data. Secondly, the cohort is relatively small with 29 patients included. However, the incidence of patients requiring prior mesh removal for infection is low even in referral, specialized, and tertiary centers. In addition, as only patients with infected mesh (grade 3c of the modified VHWG classification) and no other type of contaminations (clean-contaminated or 3a/3b grades) were included, the homogeneity of the cohort was improved facilitating data interpretation and future comparisons. Another limitation was the absence of a control group or comparator (e.g., biological mesh, suture repair, or mesh salvage). This decreases the strength of the conclusion that can be drawn from this article. It must be kept in mind that depending on individual case conditions mesh salvage can be achieved with antibiotherapy and surgical wound debridement in a high number of cases. The presented strategy can be used in specific situations where multiple risk factors of conservative treatment failure are present. It can also be mentioned that the median follow-up (17 months) was potentially not long enough to find recurrence as the resorption time of the poly-4-hydroxybutyrate is estimated to be between 12 and 18 months. The fact that the decision to perform a one- or two-stage procedure was left to the surgeon’s discretion might limit the reproducibility of the presented strategy. Finally, data on antibiotherapy prescription and duration, and types of micro-organisms were not available at time of data collection and were not included in the database of this study.

Based on the current findings, future studies should strive to specify predictive criteria defining when the presented strategy gives the best outcomes in case of infected mesh. Moreover, the antibiotherapy strategy and location of the mesh placement in this context remain unelucidated.

In conclusion, mesh removal followed by implantation of a long-term absorbable mesh with or without prior VAC therapy had in this cohort a high postoperative morbidity but good long-term results in terms of mesh removal and hernia recurrence rate. Prospective data and larger cohorts would help to confirm the preliminary outcomes of the use of long-term absorbable meshes in patients with prior infected mesh in acute and chronic contexts.