Evidence for Replacement of an Infected Synthetic by a Biological Mesh in Abdominal Wall Hernia Repair

Mesh repair versus non-mesh repair for incarcerated and strangulated groin hernia: an updated systematic review and meta-analysis

BACKGROUND

Mesh repair in incarcerated or strangulated groin hernia is controversial, especially when bowel resection is required. We aimed to perform a meta-analysis comparing mesh and non-mesh repair in patients undergoing emergency groin hernia repair.

METHODS

We performed a literature search of databases to identify studies comparing mesh and primary suture repair of patients with incarcerated or strangulated inguinal or femoral hernias who underwent emergency surgery. Postoperative outcomes were assessed by pooled analysis and meta-analysis. Statistical analysis was performed using RevMan 5.4. Heterogeneity was assessed with I2 statistics.

RESULTS

1095 studies were screened and 101 were thoroughly reviewed. Twenty observational studies and four randomized controlled trials comprising 12,402 patients were included. We found that mesh-based repair had reduced recurrence (OR 0.36; 95% CI 0.19, 0.67; P = 0.001; I2 = 35%), length of hospital stay (OR - 1.02; 95% CI - 1.87, - 0.17; P = 0.02; I2 = 94%) and operative time (OR - 9.21; 95% CI - 16.82, - 1.61; P = 0.02; I2 = 95%) without increasing surgical site infection, mortality or postoperative complications such as seroma, chronic, ileus or urinary retention. In the subgroup analysis of patients that underwent bowel resection, we found that mesh repair was associated with an increased risk of surgical site infection (OR 1.74; 95% CI 1.04, 2.91; P = 0.04; I2 = 9%).

CONCLUSIONS

Mesh repair for incarcerated and strangulated groin hernias reduces recurrence without an increase in postoperative complications and should be considered in clean cases. However, in the setting of bowel resection, mesh repair might increase the incidence of surgical site infection.

Polyglactin 910 Meshes Coated with Sustained-Release Cannabigerol Varnish Inhibit Staphylococcus aureus Biofilm Formation and Macrophage Cytokine Secretion: An In Vitro Study

Synthetic surgical meshes are commonly used in abdominal wall reconstruction surgeries to strengthen a weak abdominal wall. Common mesh-related complications include local infection and inflammatory processes. Because cannabigerol (CBG) has both antibacterial and anti-inflammatory properties, we proposed that coating VICRYL (polyglactin 910) mesh with a sustained-release varnish (SRV) containing CBG would prevent these complications. We used an in vitro infection model with Staphylococcus aureus and an in vitro inflammation model of lipopolysaccharide (LPS)-stimulated macrophages. Meshes coated with either SRV-placebo or SRV-CBG were exposed daily to S. aureus in tryptic soy medium (TSB) or macrophage Dulbecco's modified eagle medium (DMEM). Bacterial growth and biofilm formation in the environment and on the meshes were assessed by changes in optical density, bacterial ATP content, metabolic activity, crystal violet staining, spinning disk confocal microscopy (SDCM), and high-resolution scanning electron microscopy (HR-SEM). The anti-inflammatory effect of the culture medium that was exposed daily to the coated meshes was analyzed by measuring the release of the cytokines IL-6 and IL-10 from LPS-stimulated RAW 264.7 macrophages with appropriate ELISA kits. Additionally, a cytotoxicity assay was performed on Vero epithelial cell lines. We observed that compared with SRV-placebo, the segments coated with SRV-CBG inhibited the bacterial growth of S. aureus in the mesh environment for 9 days by 86 ± 4% and prevented biofilm formation and metabolic activity in the surroundings for 9 days, with respective 70 ± 2% and 95 ± 0.2% reductions. The culture medium that was incubated with the SRV-CBG-coated mesh inhibited LPS-induced secretion of IL-6 and IL-10 from the RAW 264.7 macrophages for up to 6 days without affecting macrophage viability. A partial anti-inflammatory effect was also observed with SRV-placebo. The conditioned culture medium was not toxic to Vero epithelial cells, which had an IC₅₀ of 25 µg/mL for CBG. In conclusion, our data indicate a potential role of coating VICRYL mesh with SRV-CBG in preventing infection and inflammation in the initial period after surgery.

Incisional hernia repair after kidney transplantation in a tertiary high-volume center: outcomes from a 10-year retrospective cohort study

BACKGROUND AND AIM

Incisional hernia (IH) after Kidney Transplantation (KT) is a challenging complication due to both technical reasons and patients' complexity. Data regarding outcomes of hernia repair in KT recipients are uncertain, since the biggest part of previous papers focused on risk factors for incisional hernia occurrence and not on its outcomes. Aim of the study was to focus on risk factors for incisional hernia recurrence after surgical repair in KT recipients.

METHODS

Data regarding all consecutive patients undergoing kidney transplantations from January 2011 until September 2020 in Montpellier University Hospital were retrospectively collected from a single institutional database.

RESULTS

After a median follow-up of 48 months (IQR_25-75 31-59), data from 1546 consecutive KT were collected. 83 patients underwent 99 incisional hernia surgeries after KT, with 14 patients that had one recurrence (14.4%) and 2 patients that experienced two recurrences (2.4%). Total recurrence rate was 16.8%. At univariate analysis, the only factor associated with an incisional hernia recurrence was having undergone to at least one previous abdominal surgery other than KT (p value 0.002). Overall morbidity was 15% (n = 15), with most of complications classified as mild (59%). No mortality related to incisional hernia repair occurred.

CONCLUSION

IHs after KT represent an important condition. Its surgical management is challenging due to its anatomical complexity and patient's status. This is the largest sample size in the literature of patients treated for IH after KT and it shows that a previous surgery other than the KT is a risk factor for hernia recurrence after surgical repair, without regarding surgical technique or other comorbidity and therapeutical factors.

WSES/GAIS/WSIS/SIS-E/AAST global clinical pathways for patients with skin and soft tissue infections

Skin and soft-tissue infections (SSTIs) encompass a variety of pathological conditions that involve the skin and underlying subcutaneous tissue, fascia, or muscle, ranging from simple superficial infections to severe necrotizing infections.

Together, the World Society of Emergency Surgery, the Global Alliance for Infections in Surgery, the Surgical Infection Society-Europe, The World Surgical Infection Society, and the American Association for the Surgery of Trauma have jointly completed an international multi-society document to promote global standards of care in SSTIs guiding clinicians by describing reasonable approaches to the management of SSTIs.

An extensive non-systematic review was conducted using the PubMed and MEDLINE databases, limited to the English language. The resulting evidence was shared by an international task force with different clinical backgrounds.

Risks and Prevention of Surgical Site Infection After Hernia Mesh Repair and the Predictive Utility of ACS-NSQIP

AIM

The aim of this paper was to provide a narrative review of surgical site infection after hernia surgery and the influence of perioperative preventative interventions.

METHODS

The review was based on current national and international guidelines and a literature search.

RESULTS

Mesh infection is a highly morbid complication after hernia surgery, and is associated with hospital re-admission, increased health care costs, re-operation, hernia recurrence, impaired quality of life and plaintiff litigation. The American College of Surgeons National Surgical Quality Improvement Program is a particularly useful resource for the study and evidence-based practise of abdominal wall hernia repair.

DISCUSSION

The three major modifiable patient comorbidities significantly associated with postoperative surgical site infection in hernia surgery are obesity, tobacco smoking and diabetes mellitus. Preoperative optimization includes weight loss, cessation of smoking, and control of diabetes. Intraoperative interventions relate, in particular, to the control of fomite mediated transmission in the operating theatre and prevention of mesh contamination with S. aureus CFUs. Risk management strategies should also target the niche ecological conditions which enable bacterial survival and subsequent biofilm formation on an implanted mesh. Outcomes of mesh infection after hernia surgery are closely related to mesh type and porosity, patient smoking status, presence of MRSA, bacterial adhesion and biofilm production. The use of suction drains and the timing of drain removal are controversial and discussed in detail. Finally, the utility of the ACS-NSQIP Surgical Risk Calculator in predicting complications and outcomes in individual patients and the importance of quality improvement initiatives in surgical units are emphasized.

A multi-center study on recurrent inguinal hernias: assessment of surgeons' compliance to guideline-based repair and evaluation of short-term outcomes

INTRODUCTION

As patients with recurrent inguinal hernia (RIH) are at a higher risk of perioperative complications, international guidelines have been developed to mitigate these risks by recommending the reverse approach for repair. We aim to study the characteristics of RIH, compliance to guidelines-based repair (GR) and determine factors influencing compliance to guidelines.

METHODS

A retrospective study of patients with RIH was carried out at two tertiary institutions in Singapore, over 10 years from January 2010 to 2020.

RESULTS

There were 16 patients with bilateral recurrences and 214 patients with unilateral recurrences. The characteristics of patients with non-guidelines-based repair (NGR) versus GR were similar, p > 0.05. GR was performed for 128 (52.1%) hernias as compared to NGR for 118 (47.9%) hernias. The open approach was more common in NGR than GR, 115/118 (89.8%) versus 58/128 (45.3%), p < 0.001. Forty (n = 40, 16.3%) RIH presented emergently, of which 37 underwent NGR while 3 underwent GR, p < 0.0001. More consultants were present during GR 103/128 (80.5%) as compared to NGR 78/118 (66.1%), p = 0.018. Emergency presentation of hernia recurrence, OR 7.74 (CI 6.11-9.20), p = 0.005, and open repair during the index repair were significantly associated with NGR, OR 6.63 (CI 4.42-8.84), p = 0.01. Median length of stay was shorter in the GR 1 day (IQR 1-2 days) versus 2 days (IQR 2-5 days) in the NGR group, p = 0.02.

CONCLUSION

The compliance rate of GR for RIH is 52%. NGR for RIH had acceptable short-term outcomes. For elective presentation of RIH, GR should be encouraged given a shorter length of hospital stay.

Antibacterial Biopolymer Gel Coating on Meshes Used for Abdominal Hernia Repair Promotes Effective Wound Repair in the Presence of Infection

Prosthetic mesh infection is a devastating complication of abdominal hernia repair which impairs natural healing in the implant area, leading to increased rates of patient morbidity, mortality, and prolonged hospitalization. This preclinical study was designed to assess the effects on abdominal wall tissue repair of coating meshes with a chlorhexidine or rifampicin-carboxymethylcellulose biopolymer gel in a Staphylococcus aureus (S. aureus) infection model. Partial abdominal wall defects were created in New Zealand white rabbits (n = 20). Four study groups were established according to whether the meshes were coated or not with each of the antibacterial gels. Three groups were inoculated with S. aureus and finally repaired with lightweight polypropylene mesh. Fourteen days after surgery, implanted meshes were recovered for analysis of the gene and protein expression of collagens, macrophage phenotypes, and mRNA expression of vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMPs). Compared to uncoated meshes, those coated with either biopolymer gel showed higher collagen 1/3 messenger RNA and collagen I protein expression, relatively increased VEGF mRNA expression, a significantly reduced macrophage response, and lower relative amounts of MMPs mRNAs. Our findings suggest that following mesh implant these coatings may help improving abdominal wall tissue repair in the presence of infection.

Fascinating history of groin hernias: Comprehensive recognition of anatomy, classic considerations for herniorrhaphy, and current controversies in hernioplasty

Groin hernias include indirect inguinal, direct inguinal, femoral, obturator, and supravesical hernias. Here, we summarize historical turning points, anatomical recognition and surgical repairs. Groin hernias have a fascinating history in the fields of anatomy and surgery. The concept of tension-free repair is generally accepted among clinicians. Surgical repair with mesh is categorized as hernioplasty, while classic repair without mesh is considered herniorrhaphy. Although various surgical approaches have been developed, the surgical technique should be carefully chosen for each patient. Regarding as interesting history, crucial anatomy and important surgeries in the field of groin hernia, we here summarized them in detail, respectively. Points of debate are also reviewed; important points are shown using illustrations and schemas. We hope this systematic review is surgical guide for general surgeons including residents. Both a skillful technique and anatomical knowledge are indispensable for successful hernia surgery in the groin.

Development of Biocomposite Polymeric Systems Loaded with Antibacterial Nanoparticles for the Coating of Polypropylene Biomaterials

The development of a biocomposite polymeric system for the antibacterial coating of polypropylene mesh materials for hernia repair is reported. Coatings were constituted by a film of chitosan containing randomly dispersed poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles loaded with chlorhexidine or rifampicin. The chlorhexidine-loaded system exhibited a burst release during the first day reaching the release of the loaded drug in three or four days, whereas rifampicin was gradually released for at least 11 days. Both antibacterial coated meshes were highly active against Staphylococcus aureus and Staphylococcus epidermidis (10⁶ CFU/mL), displaying zones of inhibition that lasted for 7 days (chlorhexidine) or 14 days (rifampicin). Apparently, both systems inhibited bacterial growth in the surrounding environment, as well as avoided bacterial adhesion to the mesh surface. These polymeric coatings loaded with biodegradable nanoparticles containing antimicrobials effectively precluded bacterial colonization of the biomaterial. Both biocomposites showed adequate performance and thus could have potential application in the design of antimicrobial coatings for the prophylactic coating of polypropylene materials for hernia repair.

Thermo-Responsive Antimicrobial Hydrogel for the In-Situ Coating of Mesh Materials for Hernia Repair

The prophylactic coating of prosthetic mesh materials for hernia repair with antimicrobial compounds is commonly performed before implantation of the mesh in the abdominal wall. We propose a novel alternative, which is a rifampicin-loaded thermo-responsive hydrogel formulation, to be applied on the mesh after its implantation. This formulation becomes a gel in-situ once reached body temperature, allowing an optimal coating of the mesh along with the surrounding tissues. In vitro, the hydrogel cytotoxicity was assessed using rabbit fibroblasts and antimicrobial efficacy was determined against Staphylococcus aureus. An in vivo rabbit model of hernia repair was performed; implanted polypropylene meshes (5 × 2 cm) were challenged with S. aureus (10⁶ CFU), for two study groups—unloaded (n = 4) and 0.1 mg/cm² rifampicin-loaded hydrogel (n = 8). In vitro, antibacterial activity of the hydrogel lasted for 5 days, without sign of cytotoxicity. Fourteen days after implantation, meshes coated with drug-free hydrogel developed a strong infection and resulted in poor tissue integration. Coating meshes with the rifampicin-loaded hydrogel fully prevented implant infection and permitted an optimal tissue integration. Due to its great performance, this, degradable, thermo-responsive antimicrobial hydrogel could potentially be a strong prophylactic armamentarium to be combined with prosthesis in the surgical field.

Experimental study on the use of a chlorhexidine-loaded carboxymethylcellulose gel as antibacterial coating for hernia repair meshes

PURPOSE

Biomaterials with an antimicrobial coating could avoid mesh-associated infection following hernia repair. This study assesses the use of a chlorhexidine-loaded carboxymethylcellulose gel in a model of Staphylococcus aureus mesh infection.

METHODS

A 1% carboxymethylcellulose gel containing 0.05% chlorhexidine was prepared and tested in vitro and in vivo. The in vitro tests were antibacterial activity (S. aureus; agar diffusion test) and gel cytotoxicity compared to aqueous 0.05% chlorhexidine (fibroblasts; alamarBlue). For the in vivo study, partial abdominal wall defects (5 × 2 cm) were created in New Zealand white rabbits (n = 15) and inoculated with 0.25 mL of S. aureus (10⁶ CFU/mL). Defects were repaired with a lightweight polypropylene mesh (Optilene) without coating (n = 3) or coated with a carboxymethylcellulose gel (n = 6) or chlorhexidine-loaded carboxymethylcellulose gel (n = 6). Fourteen days after surgery, bacterial adhesion to the implant (sonication, immunohistochemistry), host tissue incorporation (light microscopy) and macrophage reaction (immunohistochemistry) were examined.

RESULTS

Carboxymethylcellulose significantly reduced the toxicity of chlorhexidine (p < 0.001) without limiting its antibacterial activity. While control and gel-coated implants were intensely contaminated, the chlorhexidine-gel-coated meshes showed a bacteria-free surface, and only one specimen showed infection signs. The macrophage reaction in this last group was reduced compared to the control (p < 0.05) and gel groups.

CONCLUSIONS

When incorporated in the carboxymethylcellulose gel, chlorhexidine showed reduced toxicity yet maintained its bactericidal effect at the surgery site. Our findings suggest that this antibacterial gel-coated polypropylene meshes for hernia repair prevent bacterial adhesion to the mesh surface and have no detrimental effects on wound repair.

Open darn repair vs open mesh repair of inguinal hernia: a systematic review and meta-analysis of randomised and non-randomised studies

OBJECTIVES

To compare the outcomes of open darn repair vs open mesh repair in patients undergoing inguinal hernia repair.

METHODS

We performed a systematic review and conducted a search of electronic information sources to identify all observational studies and randomised controlled trials (RCTs) investigating outcomes of open darn repair vs open mesh repair for inguinal hernias. Hernia recurrence was considered as the primary outcome measure. The secondary outcome measures included surgical site infection (SSI), haematoma, seroma, neuralgia, urinary retention, length of hospital stay, time to return to normal activities or work, testicular atrophy, operative time and chronic pain. Random or fixed effects modelling was applied to calculate pooled outcome data.

RESULTS

Six RCTs, enrolling 1480 patients with 1485 hernias, and 4 observational studies, enrolling 1564 patients with 1641 hernias, were included. Meta-analysis of RCTs showed no significant difference in terms of recurrence (RD 0.00, 95% CI - 0.01 to 0.01, P = 0.86), SSI (OR 0.83, 95% CI 0.46-1.49, P = 0.52), haematoma (OR 1.21, 95% CI 0.62-2.38, P = 0.57), seroma (OR 0.83, 95% CI 0.42-1.65, P = 0.60), neuralgia (OR 1.05, 95% CI 0.29-3.73, P = 0.94), urinary retention (OR 1.44, 95% CI 0.64-3.21, P = 0.38), length of hospital stay (MD 0.09, 95% CI - 0.28 to 0.46, P = 0.63), time to return to normal activities or work (MD 0.88, 95% CI - 0.90 to 2.66, P = 0.33), testicular atrophy (RD 0.00, 95% CI - 0.02 to 0.02, P = 1.00), and operative time (MD 2.69, 95% CI - 1.75 to 7.14, P = 0.62) between the darn repair and mesh repair groups. Meta-analysis of observational studies also showed no significant difference in terms of recurrence (RD 0.00, 95% CI - 0.02 to 0.02, P = 0.99), SSI (OR 0.47, 95% CI 0.14-1.62, P = 0.23), haematoma (OR 1.07, 95% CI 0.45-2.55, P = 0.89), seroma (OR 0.12, 95% CI 0.01-2.27, P = 0.16), neuralgia (OR 0.25, 95% CI 0.05-1.21, P = 0.08), urinary retention (OR 1.53, 95% CI 0.20-11.96, P = 0.69), time to return to normal activities or work (MD 2.13, 95% CI - 2.18 to 6.44, P = 0.33), testicular atrophy (RD - 0.01, 95% CI - 0.02 to 0.01, P = 0.49), and operative time (MD - 4.76, 95% CI - 13.23 to 3.71, P = 0.27) between the two groups. The evidence was inconclusive for chronic pain. The quality of available evidence was moderate.

CONCLUSIONS

Our results suggest that open darn repair is comparable with open mesh repair for inguinal hernias. Considering that consequences of mesh complications in inguinal hernia repair, albeit rare, can be significant, open darn repair provides an equally credible alternative to open mesh repair for inguinal hernias. Further studies are required to investigate patient-reported outcomes and to elicit a superior non-mesh technique.

What is the evidence for the use of biologic or biosynthetic meshes in abdominal wall reconstruction?

INTRODUCTION

Although many surgeons have adopted the use of biologic and biosynthetic meshes in complex abdominal wall hernia repair, others have questioned the use of these products. Criticism is addressed in several review articles on the poor standard of studies reporting on the use of biologic meshes for different abdominal wall repairs. The aim of this consensus review is to conduct an evidence-based analysis of the efficacy of biologic and biosynthetic meshes in predefined clinical situations.

METHODS

A European working group, "BioMesh Study Group", composed of invited surgeons with a special interest in surgical meshes, formulated key questions, and forwarded them for processing in subgroups. In January 2016, a workshop was held in Berlin where the findings were presented, discussed, and voted on for consensus. Findings were set out in writing by the subgroups followed by consensus being reached. For the review, 114 studies and background analyses were used.

RESULTS

The cumulative data regarding biologic mesh under contaminated conditions do not support the claim that it is better than synthetic mesh. Biologic mesh use should be avoided when bridging is needed. In inguinal hernia repair biologic and biosynthetic meshes do not have a clear advantage over the synthetic meshes. For prevention of incisional or parastomal hernias, there is no evidence to support the use of biologic/biosynthetic meshes. In complex abdominal wall hernia repairs (incarcerated hernia, parastomal hernia, infected mesh, open abdomen, enterocutaneous fistula, and component separation technique), biologic and biosynthetic meshes do not provide a superior alternative to synthetic meshes.

CONCLUSION

The routine use of biologic and biosynthetic meshes cannot be recommended.

2018 WSES/SIS-E consensus conference: recommendations for the management of skin and soft-tissue infections

Skin and soft-tissue infections (SSTIs) encompass a variety of pathological conditions that involve the skin and underlying subcutaneous tissue, fascia, or muscle, ranging from simple superficial infections to severe necrotizing infections. SSTIs are a frequent clinical problem in surgical departments. In order to clarify key issues in the management of SSTIs, a task force of experts met in Bertinoro, Italy, on June 28, 2018, for a specialist multidisciplinary consensus conference under the auspices of the World Society of Emergency Surgery (WSES) and the Surgical Infection Society Europe (SIS-E). The multifaceted nature of these infections has led to a collaboration among general and emergency surgeons, intensivists, and infectious disease specialists, who have shared these clinical practice recommendations.

The Impact of Body Mass Index on Abdominal Wall Reconstruction Outcomes: A Comparative Study

BACKGROUND

Obesity and higher body mass index may be associated with higher rates of wound healing complications and hernia recurrence rates following complex abdominal wall reconstruction. The authors hypothesized that higher body mass indexes result in higher rates of postoperative wound healing complications but similar rates of hernia recurrence in abdominal wall reconstruction patients.

METHODS

The authors included 511 consecutive patients who underwent abdominal wall reconstruction with underlay mesh. Patients were divided into three groups on the basis of preoperative body mass index: less than 30 kg/m (nonobese), 30 to 34.9 kg/m (class I obesity), and 35 kg/m or greater (class II/III obesity). The authors compared postoperative outcomes among these groups.

RESULTS

Class I and class II/III obesity patients had higher surgical-site occurrence rates than nonobese patients (26.4 percent versus 14.9 percent, p = 0.006; and 36.8 percent versus 14.9 percent, p < 0.001, respectively) and higher overall complication rates (37.9 percent versus 24.7 percent, p = 0.007; and 43.4 percent versus 24.7 percent, p < 0.001, respectively). Similarly, obese patients had significantly higher skin dehiscence (19.3 percent versus 7.2 percent, p < 0.001; and 26.5 percent versus 7.2 percent, p < 0.001, respectively) and fat necrosis rates (10.0 percent versus 2.1 percent, p = 0.001; and 11.8 percent versus 2.1 percent, p < 0.001, respectively) than nonobese patients. Obesity class II/III patients had higher infection and seroma rates than nonobese patients (9.6 percent versus 4.3 percent, p = 0.041; and 8.1 percent versus 2.1 percent, p = 0.006, respectively). However, class I and class II/III obesity patients experienced hernia recurrence rates (11.4 percent versus 7.7 percent, p = 0.204; and 10.3 percent versus 7.7 percent, p = 0.381, respectively) and freedom from hernia recurrence (overall log-rank, p = 0.41) similar to those of nonobese patients.

CONCLUSION

Hernia recurrence rates do not appear to be affected by obesity on long-term follow-up in abdominal wall reconstruction.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, II.

Primary fascial closure with biologic mesh reinforcement results in lesser complication and recurrence rates than bridged biologic mesh repair for abdominal wall reconstruction: A propensity score analysis

BACKGROUND

Previous studies suggest that bridged mesh repair for abdominal wall reconstruction may result in worse outcomes than mesh-reinforced, primary fascial closure, particularly when acellular dermal matrix is used. We compared our outcomes of bridged versus reinforced repair using ADM in abdominal wall reconstruction procedures.

METHODS

This retrospective study included 535 consecutive patients at our cancer center who underwent abdominal wall reconstruction either for an incisional hernia or for abdominal wall defects left after excision of malignancies involving the abdominal wall with underlay mesh. A total of 484 (90%) patients underwent mesh-reinforced abdominal wall reconstruction and 51 (10%) underwent bridged repair abdominal wall reconstruction. Acellular dermal matrix was used, respectively, in 98% of bridged and 96% of reinforced repairs. We compared outcomes between these 2 groups using propensity score analysis for risk-adjustment in multivariate analysis and for 1-to-1 matching.

RESULTS

Bridged repairs had a greater hernia recurrence rate (33.3% vs 6.2%, P < .001), a greater overall complication rate (59% vs 30%, P = .001), and worse freedom from hernia recurrence (log-rank P <.001) than reinforced repairs. Bridged repairs also had a greater rate of wound dehiscence (26% vs 14%, P = .034) and mesh exposure (10% vs 1%, P = .003) than mesh-reinforced abdominal wall reconstruction. When the treatment method was adjusted for propensity score in the propensity-score-matched pairs (n = 100), we found that the rates of hernia recurrence (32% vs 6%, P = .002), overall complications (32% vs 6%, P = .002), and freedom from hernia recurrence (68% vs 32%, P = .001) rates were worse after bridged repair. We did not observe differences in wound healing and mesh complications between the 2 groups.

CONCLUSION

In our population of primarily cancer patients at MD Anderson Cancer Center bridged repair for abdominal wall reconstruction is associated with worse outcomes than mesh-reinforced abdominal wall reconstruction. Particularly when employing acellular dermal matrix, reinforced repairs should be used for abdominal wall reconstruction whenever possible.

In vitro assessment of an antibacterial quaternary ammonium-based polymer loaded with chlorhexidine for the coating of polypropylene prosthetic meshes

PURPOSE

This study assesses the use of an absorbable polymer loaded with chlorhexidine (CHX) as an antibacterial coating for polypropylene (PP) meshes employed in hernia repair.

METHODS

The polymer N,N-dimethyl-N-benzyl-N-(2-methacryloyloxyethyl) ammonium bromide was loaded with CHX (1 % w/w). Fragments (1 cm²) of Optilene^® Mesh Elastic were coated either with the unloaded (POL) or CHX-loaded polymer (POL-CHX). Uncoated fragments (PP) served as controls. The release kinetics of the POL-CHX coating was monitored by HPLC. Sterile fragments were placed on agar plates previously contaminated with 10⁶ CFU of Staphylococcus aureus (Sa) ATCC25923, Staphylococcus epidermidis (Se) ATCC12228, or Escherichia coli (Ec) ATCC25922 and incubated at 37 °C for 1/2/7 days. At each time point, inhibition halos were measured and bacterial adhesion to the meshes quantified by sonication and scanning electron microscopy. Coating cytotoxic effects were examined on cultured fibroblasts.

RESULTS

The polymer coating gradually released CHX over 3 days. Inhibition halos were produced only around the POL-CHX-coated meshes and these were significantly smaller for Ec than Sa or Se (p < 0.01). While POL-CHX prevented bacterial adhesion to the mesh, the reduced bacterial yields over time were observed for the POL-coated versus control PP meshes (p < 0.001). By day 7, only Ec remained attached to the surface of control meshes. The POL coating was not cytotoxic, yet POL-CHX reduced the viability of cultured fibroblasts.

CONCLUSIONS

When loaded with the antiseptic CHX, this quaternary ammonium-based polymer coating released its contents in a controlled manner indicating its potential prophylactic use to reduce the risk of infection following PP mesh implantation.