Mesh Infection and Hernia Repair: A Review

The Usage of Mesh and Relevant Prognosis in Implant Breast Reconstruction Surgery: A Meta-analysis

BACKGROUND

Although mesh-based implant breast reconstruction surgery is emerging as the primary surgical procedure for breast reconstruction, mesh use remains controversial in implant breast reconstruction surgery, especially in terms of how to select the ideal mesh. Our aim is to elaborate relevant prognosis in the mesh-based implant breast reconstruction surgery.

METHODS

Relevant studies were identified from PubMed, Web of Science, EMBASE, and Cochrane library searches. Extracted data included study type, basic characteristics, mesh information, complications, etc. We analyzed the included cohort studies and randomized controlled trials that reported mesh-related implant breast reconstruction complications and breast quality scale scores.

RESULTS

A total of 32 studies including 7475 subjects were included. The results showed that the overall complication rate was 2.07 times higher in the biological mesh group than in the synthetic mesh group (risk ratio [RR]: 2.07, 95% CI 1.14-3.78). The risk of seroma was 4.50 times higher in the biological mesh group than in the synthetic mesh group (RR: 4.50, 95% CI 2.27-8.95). In terms of comparing breast quality scale scores, the mesh group had scores that were 1.49 (95% CI 0.19-2.78) higher than the non-mesh group for "physical well-being" and 2.05 (95% CI 0.08-4.02) higher for "sexual well-being."

CONCLUSIONS

Our study found that the risk of total complications was higher with biological mesh than with synthetic mesh in implant breast reconstruction surgery. Based on short-term cost, healthcare burden, and healthcare benefits, synthetic meshes are superior to biological meshes.

LEVEL OF EVIDENCE III

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Polysaccharide-Based Coating with Excellent Antibiofilm and Repeatable Antifouling-Bactericidal Properties for Treating Infected Hernia

In recent years, the utilization of medical devices has gradually increased and implantation procedures have become common treatments. However, patients are susceptible to the risk of implant infections. This study utilized chemical grafting to immobilize polyethylenimine (QPEI) and hyaluronic acid (HA) on the surface of the mesh to improve biocompatibility while being able to achieve antifouling antimicrobial effects. From the in vitro testing, PP-PDA-Q-HA exhibited a high antibacterial ratio of 93% against S. aureus, 93% against E. coli, and 85% against C. albicans. In addition, after five rounds of antimicrobial testing, the coating continued to exhibit excellent antimicrobial properties; PP-PDA-Q-HA also inhibits the formation of bacterial biofilms. In addition, PP-PDA-Q-HA has good hemocompatibility and cytocompatibility. In vivo studies in animal implantation infection models also demonstrated the excellent antimicrobial properties of PP-PDA-Q-HA. Our study provides a promising strategy for the development of antimicrobial surface medical materials with excellent biocompatibility.

Next generation meshes for hernia repair: Polypropylene meshes coated with antimicrobial benzalkonium chloride induced proliferative activity of fibroblasts

Hernia repair is one of the most frequently performed world-wide surgical procedures in which hernia meshes are becoming increasingly used. Polypropylene (PP) mesh implants reduce the risk of recurrence and post-operative pain, although many other risks are associated with it, such as bacterial infection. In this study we developed PP meshes coated with the well-known antimicrobial compound, benzalkonium chloride (BAK) by dip-coating. Several dilutions (40, 20, 30, 10, 7.5, 5, 2.5, 1, 0.5, 0.1 and 0.05 % v/v) of commercial BAK solution (BAK diluted in 70 % ethyl alcohol at 0.1 % w/v) were used to produce antimicrobial meshes with different amounts of BAK. The dip-coating treatment with low concentrations of BAK (1, 0.5, 0.1 and 0.05 % v/v dilutions) was found to have biocompatible results in fibroblast. The use of 0.1 and 0.05 % v/v dilutions (PP meshes with up to ∼2 % w/w of BAK) showed proliferative activity on fibroblast cells, indicating that these novel antimicrobial meshes show great promise for hernia repair due to their ability to prevent infections while inducing fibroblast proliferation.

Quality of life assessment of patients after removal of late-onset infected mesh following open tension-free inguinal hernioplasty: 3-year follow-up

PURPOSE

Open tension-free inguinal hernioplasty is one of the common surgical methods used today to treat inguinal hernias due to its simplicity and low recurrence rate. With the widespread use of tension-free inguinal hernia repair, the number of patients with mesh infections is gradually increasing. However, there is a lack of studies assessing the quality of life of patients after the removal of late-onset infected meshes in open inguinal hernias. The aim of this study was to analyse and assess the quality of life, pain severity and anxiety of patients after late-onset infection mesh removal following open inguinal hernioplasty.

METHODS

Data from 105 patients admitted to our hospital from January 2014 to January 2019 who developed delayed mesh infection after open tension-free inguinal hernia repair were retrospectively analysed. 507 patients without mesh infection after open inguinal hernioplasty were included as cross-sectional controls. The baseline data of the two groups were matched for propensity score matching (PSM) with a caliper value of 0.05 and a matching ratio of 1:1. Patients are followed up by telephone or outpatient consultations for 3 years to assess quality of life, pain and anxiety after removal of the infected mesh.

RESULTS

The 105 patients who developed late-onset mesh infection after inguinal hernia repair had a mean age of 64.07 ± 12.90 years and a mean body mass index (BMI) of 24.64 ± 2.67 (kg/m2). The mean follow-up time was 58 months and 10.5% (10/105) of the patients were lost to follow-up. At the 3-year follow-up there was one case of hernia recurrence and five cases of mesh reinfection. The patients' quality of life scores, pain scores and anxiety scores improved after surgery compared to the preoperative scores (all p < 0.01).

CONCLUSION

Patients with late-onset mesh infection after inguinal hernioplasty showed an improvement in quality of life, pain and anxiety compared to preoperative after removal of the infected mesh. Mesh-plug have a higher risk of mesh infection due to their poor histocompatibility and tendency to crumple and shift.

Hernia Mesh Complications: Management of Mesh Infections and Enteroprosthetic Fistula

The potential consequences of mesh infection mandate careful consideration of surgical approach, mesh selection, and preoperative patient optimization when planning for ventral hernia repair. Intraperitoneal mesh, microporous or laminar mesh, and multifilament mesh typically require explantation, whereas macroporous, monofilament mesh in an extraperitoneal position is often salvageable. Delayed presentation of mesh infection should raise the suspicion for enteroprosthetic fistula when intraperitoneal mesh is present. When mesh excision is necessary, the surgeon must carefully consider both the risk of recurrent infection as well as hernia recurrence when deciding on single-stage definitive reconstruction versus primary closure with delayed reconstruction.

Treatment of recurrent hernia in peritoneal dialysis patients

Peritoneal dialysis (PD) is the most commonly used treatment for patients with end-stage renal disease and has the advantages of simple operation and low treatment costs. However, long-term PD may lead to inguinal hernia formation, which needs to be repaired as early as possible. There are many studies on this kind of hernia, but there are few reports about how to treat recurrent hernia in PD patients. Therefore, we present a case of a female PD patient who suffered from a recurrent femoral hernia after primary hernioplasty. We successfully proceeded with treatment by laparoscopic transabdominal preperitoneal hernia repair. The patient was scheduled to receive temporary haemodialysis until the normal PD dose was restored. After 36 months of follow-up, we found that there was no recurrence of hernia, and the function of the PD catheter was normal.

Predictors for surgical site infection in patients undergoing therapeutic or prophylactic intra-abdominal onlay mesh (IPOM) implantation in clean and contaminated surgical fields

BACKGROUND

Prophylactic intra-abdominal onlay mesh (IPOM) implantation has been shown to reduce the rate of fascial dehiscence and incisional hernia. However, surgical site infection (SSI) in presence of an IPOM remains a concern. The aim of this study was to assess predictors for SSI following IPOM placement in hernia and non-hernia abdominal surgery in clean and contaminated surgical fields.

METHODS

Observational study including patients undergoing IPOM placement at a Swiss tertiary care hospital 2007-2016. IPOM implantation was performed in hernia and non-hernia elective and emergency abdominal surgery, including contaminated and infected surgical fields. The incidence of SSI was prospectively assessed by Swissnoso according to CDC criteria. The effect of disease- and procedure-related factors on SSI was assessed in multivariable regression analysis, adjusting for patient-related factors.

RESULTS

A total of 1072 IPOM implantations were performed. Laparoscopy was performed in 415 patients (38.7%), laparotomy in 657 patients (61.3%). SSI occurred in 172 patients (16.0%). Superficial, deep, and organ space SSI were found in 77 (7.2%), 26 (2.4%), and 69 (6.4%) patients, respectively. Multivariable analysis revealed emergency hospitalization (OR 1.787, p = 0.006), previous laparotomy (1.745, p = 0.029), duration of operation (OR 1.193, p < 0.001), laparotomy (OR 6.167, p < 0.001), bariatric (OR 4.641, p < 0.001), colorectal (OR 1.941, p = 0.001), and emergency (OR 2.510, p < 0.001) surgery, wound class ≥ 3 (OR 3.878, p < 0.001), and non-polypropylene mesh (OR 1.818, p = 0.003) as independent predictors for SSI. Hernia surgery was independently associated with a lower risk for SSI (OR 0.165, p < 0.001).

CONCLUSION

This study revealed emergency hospitalization, previous laparotomy, duration of operation, laparotomy, as well as bariatric, colorectal, and emergency surgery, abdominal contamination or infection, and usage of non-polypropylene mesh as independent predictors for SSI. In contrast, hernia surgery was associated with a lower risk for SSI. The knowledge of these predictors will help to balance benefits of IPOM implantation against the risk for SSI.

Non-destructive processing of silver containing glass ceramic antibacterial coating on polymeric surgical mesh surfaces

Surgical meshes composed of bioinert polymers such as polypropylene are widely used in millions of hernia repair procedures to prevent the recurrence of organ protrusion from the damaged abdominal wall. However, post-operative mesh infection remains a significant complication, elevating hernia recurrence risks from 3.6% to 10%, depending on the procedure type. While attempts have been made to mitigate these infection-related complications by using antibiotic coatings, the rise in antibiotic-resistant bacterial strains threatens their effectiveness. Bioactive glass-ceramics featuring noble metals, notably silver nanoparticles (AgNPs), have recently gained traction for their wide antibacterial properties and biocompatibility. Yet, conventional methods of synthesizing and coating of such materials often require high temperatures, thus making them impractical to be implemented on temperature-sensitive polymeric substrates. To circumvent this challenge, a unique approach has been explored to deposit these functional compounds onto temperature-sensitive polypropylene mesh (PP-M) surfaces. This approach is based on the recent advancements in cold atmospheric plasma (CAP) assisted deposition of SiO2 thin films and laser surface treatment (LST), enabling the selective heating and formation of functional glass-ceramic compounds under atmospheric conditions. A systematic study was conducted to identify optimal LST conditions that resulted in the effective formation of a bioactive glass-ceramic structure without significantly altering the chemical and mechanical properties of the underlying PP-M (less than 1% change compared to the original properties). The developed coating with optimized processing conditions demonstrated high biocompatibility and persistent antibacterial properties (>7 days) against both Gram-positive and Gram-negative bacteria. The developed process is expected to provide a new stepping stone towards depositing a wide range of functional bioceramic coatings onto different implant surfaces, thereby decreasing their risk of infection and associated complications.

Fluorescence In Situ Hybridization as Diagnostic Tool for Implant-associated Infections: A Pilot Study on Added Value

Implant-associated infections are a devastating complication in surgery. Especially in infections with biofilm-forming microorganisms, the identification of the causing microorganism remains a challenge. However, the classification as biofilm is not possible with conventional polymerase chain reaction or culture-based diagnostics. The aim of this study was to evaluate the additional value of fluorescence in situ hybridization (FISH) and nucleic acid amplification technique (FISHseq) to discuss a diagnostic benefit of the culture-independent methods and to map spatial organization of pathogens and microbial biofilms in wounds.

Methods

In total, 118 tissue samples from 60 patients with clinically suspected implant-associated infections (n = 32 joint replacements, n = 24 open reduction and internal fixation, n = 4 projectiles) were analyzed using classic microbiological culture and culture-independent FISH in combination with polymerase chain reaction and sequencing (FISHseq).

Results

In 56 of 60 wounds, FISHseq achieved an added value. FISHseq confirmed the result of cultural microbiological examinations in 41 of the 60 wounds. In 12 wounds, one or more additional pathogens were detected by FISHseq. FISHseq could show that the bacteria initially detected by culture corresponded to a contamination in three wounds and could exclude that the identified commensal pathogens were a contamination in four other wounds. In five wounds, a nonplanktonic bacterial life form was detected.

Conclusions

The study revealed that FISHseq gives additional diagnostic information, including therapy-relevant findings that were missed by culture. In addition, nonplanktonic bacterial life forms could also be detected with FISHseq, albeit less frequently than previously indicated.

The role of prophylactic antibiotics in elective inguinal tension-free hernia repair: A systematic review and meta-analysis

Whether to use antibiotics to prevent surgical site infection in elective inguinal tension-free hernia repair has been controversial. To systematically evaluate the effect of prophylactic antibiotic application in elective inguinal tension-free hernia repair, we identified all published randomised controlled trials of the effect of prophylactic antibiotic application on elective inguinal tension-free hernia repair were collected by computer retrieval from the China National Knowledge Infrastructure; VIP Database; Wanfang Database; China Biomedical Literature Database; and PubMed, EMBASE and Cochrane Library databases. Meta-analysis was performed by RevMan 5.3 software. The meta-analysis showed that the total incidence of surgical site infections [P = 0.003] and the incidence of superficial surgical site infections [P = 0.004] in the antibiotic group (AG) were lower than those in the non-antibiotic group (NAG). There was no significant difference in the total incidence of postoperative infections [P = 0.06], deep surgical site infections [P = 0.26] and seroma [P = 0.52] between the AG and the NAG. Based on current evidence, the application of prophylactic antibiotics in elective inguinal tension-free hernia repair can prevent the total incidence of surgical site infections and that of superficial surgical site infections but cannot prevent the total incidence of postoperative infection events, incidence of deep surgical site infections and incidence of seroma.

What is the outcome of late-onset infected mesh removal after open tension-free inguinal hernioplasty: 3-year follow-up

PURPOSE

Reports of mesh infections following open tension-free inguinal hernioplasty are gradually increasing. Recent research has focused on identifying and managing mesh infections. However, studies examining the long-term outcomes and quality of life following mesh removal for late-onset infections are few. This study aimed to analyze the short and long-term outcomes after maximal removal of the implanted mesh in patients with late-onset mesh infection after open tension-free inguinal hernioplasty.

METHODS

Data of 105 patients who developed late-onset mesh infection after open tension-free inguinal hernioplasty and were admitted to our hospital from January 2014 to January 2019 were retrospectively analyzed. Patients were followed up by telephone or outpatient consultation for 3 years, focusing on hernia recurrence and mesh infection recurrence. Quality of life was assessed preoperatively and postoperatively using our developed scale; postoperative inguinal area pain was assessed using the visual analog score, and postoperative anxiety was assessed using the anxiety self-assessment scale.

RESULTS

Of the 105 patients who experienced late-onset mesh infection following open inguinal hernioplasty, 100 underwent mesh plug repair. The mean follow-up time was 58 months, and 10.5% (95/105) of the patients were lost to follow-up. Recurrence of infection was observed in 28.6% of patients (2/7) who underwent partial mesh removal and in 3.4% of patients (3/88) who underwent complete mesh removal. One inguinal hernia recurred 12 months after mesh removal (1.0% recurrence rate). In the third year following surgery as compared to the preoperative period, there were significant improvements in quality of life.

CONCLUSIONS

Hernia plugs may not be a good choice in tension-free inguinal hernia repair in view of the risk of late infections and fistulas. Remove all mesh at the time of the first operation for mesh infection. Hernia recurrence after late-onset infected mesh removal following open inguinal tension-free hernioplasty is rare. The post-operative quality of life, pain, and anxiety are gradually steadily improving.

Antimicrobial Meshes for Hernia Repair: Current Progress and Perspectives

Recent advances in the development of biomaterials have given rise to new options for surgery. New-generation medical devices can control chemical breakdown and resorption, prevent post-operative adhesion, and stimulate tissue regeneration. For the fabrication of medical devices, numerous biomaterials can be employed, including non-degradable biomaterials (silicone, polypropylene, expanded polytetrafluoroethylene) or biodegradable polymers, including implants and three-dimensional scaffolds for tissue engineering, which require particular physicochemical and biological properties. Based on the combination of new generation technologies and cell-based therapies, the biocompatible and bioactive properties of some of these medical products can lead to progress in the repair of injured or harmed tissue and in tissue regeneration. An important aspect in the use of these prosthetic devices is the associated infection risk, due to the medical complications and socio-economic impact. This paper provides the latest achievements in the field of antimicrobial surgical meshes for hernia repair and discusses the perspectives in the development of these innovative biomaterials.

Infección temprana de la malla quirúrgica en herniorrafia incisional. Incidencia, factores de riesgo y desenlaces en más de 60.000 pacientes

Introducción. La infección de la malla en cirugía de reparación de hernias de pared abdominal es un desenlace pobre, asociado a un incremento en el riesgo de complicaciones. El objetivo del presente estudio fue analizar la incidencia, los factores asociados y desenlaces en pacientes llevados a herniorrafia incisional con malla con posterior diagnóstico de infección temprana. Métodos. Estudio de cohorte retrospectiva. Se utilizaron los datos de egresos hospitalarios de la National Inpatient Sample (NIS) de los Estados Unidos de América para identificar a todos los pacientes adultos llevados a herniorrafia incisional durante los años 2010 a 2015. Se utilizaron modelos de regresión logística bivariada y multivariada para evaluar los factores de riesgo en infección temprana de la malla, y finalmente, modelos de regresión logística y lineal, según el tipo de variable dependiente, de tipo stepwise forward para evaluar la asociación entre el diagnóstico de infección de malla y los desenlaces adversos. Resultados. En total se incluyeron 63.925 pacientes. La incidencia de infección temprana de la malla fue de 0,59 %, encontrando como factores asociados: comorbilidades (obesidad, desnutrición proteico calórica, anemia carencial y depresión), factores clínico-quirúrgicos (adherencias peritoneales, resección intestinal, cirugía laparoscópica y complicaciones no infecciosas de la herida) y administrativos o asistenciales. Conclusiones. La infección temprana, aunque infrecuente, se asocia con un aumento significativo en el riesgo de complicaciones. La optimización prequirúrgica con base en los factores de riesgo para este desenlace nefasto es un elemento clave para la reducción de la incidencia y mitigación del impacto de la infección en los pacientes con herniorrafía incisional con malla.

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.

Systematic review and meta-analysis of risk factors for Mesh infection following Abdominal Wall Hernia Repair Surgery

BACKGROUND

Surgical Mesh Infection (SMI) after Abdominal Wall Hernia Repair (AWHR) represents a catastrophic complication. We performed a systematic review and meta-analysis to analyze the risk factors for SMI in the context of AWHR.

METHODS

PubMed, Embase, Scielo, and LILACS were searched without language or time restrictions from inception until June 2021. Articles evaluating the association between demographic, clinical, laboratory and surgical characteristics with SMI in AWHR were included.

RESULTS

23 studies were evaluated, comprising a total of 118,790 patients (98% males; mean age 56.5 years) with a mesh infection pooled prevalence of 4%. Significant risk factors for SMI were type 2 diabetes mellitus, obesity, smoking history, steroids use, ASA III/IV, laparotomy vs laparoscopy, emergency surgery, duration of surgery and onlay mesh position vs sublay. The quality of evidence was regarded as very low-moderate.

CONCLUSION

Several factors, highlighting sociodemographic characteristics, comorbidities, and the clinical scenario, may increase the risk of developing mesh infections in AWHR. The recognition and mitigation of these may significantly reduce mesh infection rates in this context.

Recent Advances in the Surface Functionalization of Nanomaterials for Antimicrobial Applications

Innovations in nanotechnology have had an immense impact on medicine, such as in drug delivery, tissue engineering, and medical devices that combat different pathogens. The pathogens that may cause biofilm-associated nosocomial diseases are multidrug-resistant (MDR) bacteria, such as Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Staphylococcus aureus (S. aureus), including both Gram-positive and Gram-negative bacterial species. About 65-80% of infections are caused by biofilm-associated pathogens creating a move in the international community toward developing antimicrobial therapies to eliminate such pathogenic infections. Several nanomaterials (NMs) have been discovered and significantly employed in various antipathogenic therapies. These NMs have unique properties of singlet oxygen production, high absorption of near-infrared irradiation, and reasonable conversion of light to heat. In this review, functionalized NPs that combat different pathogenic infections are introduced. This review highlights NMs that combat infections caused by multidrug-resistant (MDR) and other pathogenic microorganisms. It also highlights the biomedical application of NPs with regard to antipathogenic activities.

[Surgical site infections-Prevention and treatment strategies]

Surgical site infections (SSI) are the most frequent nosocomial infection in Germany. They are defined as an infection of the surgical site that occurs within 30 days after a surgical procedure. The diagnostic criteria include localized pain or tenderness, localized swelling, erythema, excess warmth, purulent drainage from the incision and cultural detection of pathogens in an aseptically obtained specimen from the incision. Wound infections are differentiated into superficial incisional (grade 1), deep incisional (grade 2) and infections of organs and body cavities in the region of the operation (grade 3). Risk factors for SSI include anemia, immunosuppression, diabetes mellitus, obesity, smoking and malnutrition. The crucial preoperative preventive measures are antisepsis of the surgical area and antibiotic prophylaxis. Intraoperative subcutaneous wound irrigation with an antiseptic solution reduces SSI in visceral surgery. The primary treatment encompasses the liberal debridement of the wound.

Infectious Complication in Relation to the Prophylactic Mesh Position: The PRIMA Trial Revisited

BACKGROUND

Prophylactic mesh reinforcement has proven to reduce the incidence of incisional hernia (IH). Fear of infectious complications may withhold the widespread implementation of prophylactic mesh reinforcement, particularly in the onlay position.

STUDY DESIGN

Patients scheduled for elective midline surgery were randomly assigned to a suture closure group, onlay mesh group, or sublay mesh group. The incidence, treatment, and outcomes of patients with infectious complications were assessed through examining the adverse event forms. Data were collected prospectively for 2 years after the index procedure.

RESULTS

Overall, infectious complications occurred in 14/107 (13.3%) patients in the suture group and in 52/373 (13.9%) patients with prophylactic mesh reinforcement (p = 0.821). Infectious complications occurred in 17.6% of the onlay group and 10.3% of the sublay group (p = 0.042). Excluding anastomotic leakage as a cause, these incidences were 16% (onlay) and 9.7% (sublay), p = 0.073. The mesh could remain in-situ in 40/52 (77%) patients with an infectious complication. The 2-year IH incidence after onlay mesh reinforcement was 10 in 33 (30.3%) with infectious complications and 15 in 140 (9.7%) without infectious complications (p = 0.003). This difference was not statistically significant for the sublay group.

CONCLUSIONS

Prophylactic mesh placement was not associated with increased incidence, severity, or need for invasive treatment of infectious complications compared with suture closure. Patients with onlay mesh reinforcement and an infectious complication had a significantly higher risk of developing an incisional hernia, compared with those in the sublay group.

Antimicrobial Peptides Grafted onto a Plasma Polymer Interlayer Platform: Performance upon Extended Bacterial Challenge

To combat infections on biomedical devices, antimicrobial coatings have attracted considerable attention, including coatings comprising naturally occurring antimicrobial peptides (AMPs). In this study the aim was to explore performance upon extended challenge by bacteria growing in media above samples. The AMPs LL37, Magainin 2, and Parasin 1 were selected on the basis of well-known membrane disruption activity in solution and were covalently grafted onto a plasma polymer platform, which enables application of this multilayer coating strategy to a wide range of biomaterials. Detailed surface analyses were performed to verify the intended outcomes of the coating sequence. Samples were challenged by incubation in bacterial growth media for 5 and 20 h. Compared with the control plasma polymer surface, all three grafted AMP coatings showed considerable reductions in bacterial colonization even at the high bacterial challenge of initial seeding at 1 × 107 CFU, but there were increasing numbers of dead bacteria attached to the surface. All three grafted AMP coatings were found to be non-toxic to primary fibroblasts. These coatings thus could be useful to produce antibacterial surface coatings for biomaterials, though possible consequences arising from the presence of dead bacteria need to be studied further, and compared to non-fouling coatings that avoid attachment of dead bacteria.

Inhibition of Angiotensin Converting Enzyme Impairs Anti-staphylococcal Immune Function in a Preclinical Model of Implant Infection

Background: Evidence suggests the renin-angiotensin system (RAS) plays key immunomodulatory roles. In particular, angiotensin-converting enzyme (ACE) has been shown to play a role in antimicrobial host defense. ACE inhibitors (ACEi) and angiotensin receptor blockers (ARB) are some of the most commonly prescribed medications, especially in patients undergoing invasive surgery. Thus, the current study assessed the immunomodulatory effect of RAS-modulation in a preclinical model of implant infection.

Methods:In vitro antimicrobial effects of ACEi and ARBs were first assessed. C57BL/6J mice subsequently received either an ACEi (lisinopril; 16 mg/kg/day), an ARB (losartan; 30 mg/kg/day), or no treatment. Conditioned mice blood was then utilized to quantify respiratory burst function as well as Staphylococcus aureus Xen36 burden ex vivo in each treatment group. S. aureus infectious burden for each treatment group was then assessed in vivo using a validated mouse model of implant infection. Real-time quantitation of infectious burden via bioluminescent imaging over the course of 28 days post-procedure was assessed. Host response via monocyte and neutrophil infiltration within paraspinal and spleen tissue was quantified by immunohistochemistry for F4/80 and myeloperoxidase, respectively.

Results: Blood from mice treated with an ACEi demonstrated a decreased ability to eradicate bacteria when mixed with Xen36 as significantly higher levels of colony forming units (CFU) and biofilm formation was appreciated ex vivo (p < 0.05). Mice treated with an ACEi showed a higher infection burden in vivo at all times (p < 0.05) and significantly higher CFUs of bacteria on both implant and paraspinal tissue at the time of sacrifice (p < 0.05 for each comparison). There was also significantly decreased infiltration and respiratory burst function of immune effector cells in the ACEi group (p < 0.05).

Conclusion: ACEi, but not ARB, treatment resulted in increased S. aureus burden and impaired immune response in a preclinical model of implant infection. These results suggest that perioperative ACEi use may represent a previously unappreciated risk factor for surgical site infection. Given the relative interchangeability of ACEi and ARB from a cardiovascular standpoint, this risk factor may be modifiable.

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.

Closure of stoma site with or without prophylactic mesh reinforcement: a systematic review and meta-analysis

AIMS

To evaluate comparative outcomes of the closure of temporary stoma site with or without prophylactic mesh reinforcement METHODS: A systematic online search was conducted using the following databases: PubMed, Scopus, Cochrane database, The Virtual Health Library, Clinical trials.gov and Science Direct. Studies comparing the reversal of stoma with and without prophylactic mesh reinforcement were included. Stoma site incisional hernia (SSIH), surgical site infection (SSI), operative time, seroma formation, haematoma formation, bowel obstruction, anastomosis leak, length of hospital stay (LOS) and secondary operation to repair the SSIH were the evaluated outcome parameters.

RESULTS

Six comparative studies reporting a total of 1683 patients who underwent closure of stoma with (n = 669) or without (n = 1014) prophylactic mesh reinforcement were included. Use of mesh was associated with a significantly lower risk of SSIH (OR 0.22, P = 0.003) and need for surgical intervention to repair SSIH (OR 0.32, P = 0.04) compared with no use of mesh. However, it was associated with significantly longer operative time (MD 47.78, P = 0.02). There was no significant difference in SSI (OR 1.09, P = 0.59), bowel obstruction (OR 1.11, P = 0.74), seroma formation (OR 2.86, P = 0.19), anastomosis leak (OR 1.60, P = 0.15), haematoma formation (OR 1.25, P = 0.75) or LOS (MD - 0.45, P = 0.31) between two groups.

CONCLUSION

Prophylactic mesh reinforcement during the closure of temporary stoma may significantly reduce the risk of SSIH and surgical intervention to repair the hernia without increasing the risk of SSI or other morbidities. However, it may increase the procedure time. Future higher-quality randomised evidence is required.

Electrospun Scaffold with Sustained Antibacterial and Tissue-Matched Mechanical Properties for Potential Application as Functional Mesh

Introduction

Various materials and approaches have been used to reduce the mesh-induced inflammatory response and modify the mesh with tissue-matched mechanical properties, aiming to improve the repair of abdominal wall defects.

Materials and Methods

In this study, we fabricated a polycaprolactone (PCL)/silk fibroin (SF) mesh integrated with amoxicillin (AMX)-incorporating multiwalled carbon nanotubes (MWCNTs) via electrospinning, grafting and crosslinking, developing a sustainable antibiotic and flexible mesh. AMX was loaded into the hollow tubular MWCNTs by physical adsorption, and a nanofibrous structure was constructed by electrospinning PCL and SF (40:60 w/w). The AMX@MWCNTs were then chemically grafted onto the surfaces of the PCL/SF nanofibers by treating with 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS) solution for simultaneous crosslinking and coating. The incorporation of AMX into the MWCNTs (AMX@MWCNTs) and the integration of the AMX@MWCNTs with the PCL/SF nanofibers were characterized. Then, the functional mesh was fabricated and fully evaluated in terms of antibacterial activity, mechanical properties and host response.

Results

Our results demonstrated that the PCL/SF nanofibrous structure was fabricated successfully by electrospinning. After integrating with AMX@MWCNT by grafting and crosslinking, the functional mesh showed undeformed structure, modified surface hydrophilicity and biocompatible interfaces, abdominal wall-matched mechanical properties, and a sustained-release antibiotic profile in E. coli growth inhibition compared to those of PCL/SF mesh in vitro. In a rat model with subcutaneous implantation, the functional mesh incited less mesh-induced inflammatory and foreign body responses than PCL/SF mesh within 14 days. The histological analysis revealed less infiltration of granulocytes and macrophages during this period, resulting in the loosely packed collagen deposition on the functional mesh and prominent collagen incorporation.

Discussion

Therefore, this designed PCL/SF-AMX@MWCNT nanofibrous mesh, functionalized with antibacterial and tissue-matched mechanical properties, provides a promising alternative for the repair of abdominal wall defects.

Porcine mesothelium matrix as a biomaterial for wound healing applications

The increasing economic burden of wound healing in healthcare systems requires the development of functional therapies. Xenografts with preserved extracellular matrix (ECM) structure and biofunctional components overcome major limitations of autografts and allografts (e.g. availability) and artificial biomaterials (e.g. foreign body response). Although porcine mesothelium is extensively used in clinical practice, it is under-investigated for wound healing applications. Herein, we compared the biochemical and biological properties of the only two commercially available porcine mesothelium grafts (Meso Biomatrix® and Puracol® Ultra ECM) to traditionally used wound healing grafts (Endoform™, ovine forestomach and MatriStem®, porcine urinary bladder) and biomaterials (Promogran™, collagen/oxidized regenerated cellulose). The Endoform™ and the Puracol® Ultra ECM showed the highest (p<0.05) soluble collagen and elastin content. The MatriStem® had the highest (p<0.05) basic fibroblast growth factor (FGFb) content, whereas the Meso Biomatrix® had the highest (p<0.05) transforming growth factor beta-1 (TGF-β1) and vascular endothelial growth factor (VEGF) content. All materials showed tissue-specific structure and composition. The Endoform™ and the Meso Biomatrix® had some nuclei residual matter. All tissue grafts showed similar (p>0.05) response to enzymatic degradation, whereas the Promogran™ was not completely degraded by matrix metalloproteinase (MMP)-8 and was completely degraded by elastase. The Promogran™ showed the highest (p<0.05) permeability to bacterial infiltration. The Promogran™ showed by far the lowest dermal fibroblast and THP-1 attachment and growth. All tested materials showed significantly lower (p<0.05) tumor necrosis factor-alpha (TNF-α) expression than the lipopolysaccharides group. The MatriStem® and the Puracol® Ultra ECM promoted the highest (p<0.05) number of micro-vessel formation, whereas the Promogran™ the lowest (p<0.05). Collectively, these data confer that porcine mesothelium has the potential to be used as a wound healing material, considering its composition, resistance to enzymatic degradation, cytocompatibility, and angiogenic potential.

The Patenting and Technological Trends in Hernia Mesh Implants

Described as a projection (prolapse) of tissue through a fascial defect in the abdominal wall, hernias are associated with significant rates of complications, recurrence, and reoperations. This literature review is aimed at providing an overview of the prosthetic surgical meshes used for the repairing of hernia defects. The review was carried out using two specialized online databases: Espacenet, from the European Patent Office (EPO), and WIPO from the World Intellectual Property Organization. Of the 56 patents selected from 2008 to 2018, China was the largest contributor with 55% (31 patents) of the total patent applicant filings, followed by the United States of America (US), with 29% (16 patents). Although the majority of patent applications (39 documents) had at least one company (industry) assigned to the patent application, 4 patents were solely from academic research. Our data showed that only 13 industry applicants have had their products included in the market, and the majority of meshes available on the market are still made from polypropylene. Chemical, physical, and mesh surface modifications have been implemented, and a few reviews describing mesh design, composition, and mechanical properties are available. However, to date, the ideal mesh implant from a clinical point of view has not been developed.

A retrospective cohort study of open preperitoneal repair versus open suture repair for the treatment of emergency femoral hernia

To compare the outcomes of open preperitoneal repair (OPR) with the use of mesh and open suture repair (OSR) without mesh via inguinal approach for the treatment of emergency femoral hernia (FH). The primary outcome was the postoperative complication and the secondary outcomes were the recurrence rate of FH and the postoperative comfort level at the surgical site. 104 patients with emergency FHs were included, of whom 51 patients were treated with OPR, 53 patients were treated with OSR. Between the two groups, no significant difference was found in surgical site infection (SSI) (P = 0.801) or seroma (P = 0.843), while there was significant difference in the improvement of comfort at the surgical site (P = 0.013). The results of the 2-year follow-up demonstrated 1 and 8 cases of recurrence in the OPR and OSR group respectively, which was statistically significant (HR, 8.193 [95% CI, 1.024 to 65.547], P = 0.047). Compared with OSR, OPR with the use of mesh did not increase the risk of SSI and was safe to apply even under the condition of an emergency FH operation with intestine resection; OPR could reduce the recurrence rate of FH and improve the comfort at the surgical site.

Well-Defined Gold Nanorod/Polymer Hybrid Coating with Inherent Antifouling and Photothermal Bactericidal Properties for Treating an Infected Hernia

Biomedical device-associated infection (BAI) is a great challenge in modern clinical medicine. Therefore, developing efficient antibacterial materials is significantly important and meaningful for the improvement of medical treatment and people's health. In the present work, we developed a strategy of surface functionalization for multifunctional antibacterial applications. A functionalized polyurethane (PU, a widely used biomedical material for hernia repairing) surface (PU-Au-PEG) with inherent antifouling and photothermal bactericidal properties was readily prepared based on a near-infrared (NIR)-responsive organic/inorganic hybrid coating which consists of gold nanorods (Au NRs) and polyethylene glycol (PEG). The PU-Au-PEG showed a high efficiency to resist adhesion of bacteria and exhibited effective photothermal bactericidal properties under 808 nm NIR irradiation, especially against multidrug-resistant bacteria. Furthermore, the PU-Au-PEG could inhibit biofilm formation long term. The biocompatibility of PU-Au-PEG was also proved by cytotoxicity and hemolysis tests. The in vivo photothermal antibacterial properties were first verified by a subcutaneous implantation animal model. Then, the anti-infection performance in a clinical scenario was studied with an infected hernia model. The results of animal experiment studies demonstrated excellent in vivo anti-infection performances of PU-Au-PEG. The present work provides a facile and promising approach to develop multifunctional biomedical devices.

Usefulness of sonication procedure in mesh infection diagnosis associated with hernia repair

BACKGROUND

The use of prosthetic meshes is a common practice in hernia repair surgery. However, infection can appear as an important complication where antibiotic selection must be directed by the etiology of the infection. In recent years, sonication has appeared as an important tool for the diagnosis of many biomaterial-associated infections. Here, we evaluated our experience with this methodology for the diagnosis of mesh infection.

METHODS

We retrospectively reviewed the microbiological records between 2015 and 2019 looking for sonicated meshes in the microbiology laboratory. All samples were processed according to the sonication protocol described by Esteban J et al. (J Clin Microbiol. 2008 Feb; 46 (2): 488-92).

RESULTS

26 samples were processed during the study period. 21 of them gave a positive result for culture (11 polymicrobial and 10 monomicrobial ones). Staphylococcus aureus and Candida albicans were the commonest monomicrobial isolates (4 cases each). There were five cases of mixed gut microbiota. The median (interquartile range) UFC count was > 100,000 (50,000- > 100,000) CFU/mL.

CONCLUSION

Sonication is a useful technique for the diagnosis of mesh infection.

Chronic mesh infection complicated by an enterocutaneous fistula successfully treated by infected mesh removal and negative pressure wound therapy: A case report

RATIONALE

Tension-free repair of inguinal hernia with prosthetic materials in adults has become a routine surgical procedure. However, serious complications may arise such as mesh displacement, infection, and even enterocutaneous fistula (EF). The management of chronic mesh infection (CMI) complicated by an EF is very challenging. A simple treatment of infected mesh removal and negative pressure wound therapy (NPWT) may cure the patients with EF with CMI.

PATIENT CONCERNS

A 75-year-old male patient underwent tension-free treatment for a bilateral inguinal hernia at a county hospital 10 years ago. Three months before admission, the right groin gradually formed a skin sinus with outflow of fetid thin pus, and it could not heal.

DIAGNOSES

The patient was diagnosed preoperatively with mesh plug adhesion to the intestine, which resulted in low-flow EF combined with CMI.

INTERVENTIONS

The patient received a simple treatment mode consisting of an incision made from the original incision, but the new incision did not penetrate the abdominal cavity; treatment included resection of the fistula, removal of the mesh, repair of the intestine and local tissue, and continuous irrigation of vacuum sealing drainage (VSD) devices for NPWT.

OUTCOMES

The infected mesh was completely removed. Five VSD devices were utilized to treat the EF and wound. The time from intervention to wound healing was 35 days, and follow-up for 6 months revealed no infection and no hernia recurrence in the right groin.

LESSONS

The NPWT is effective in treating CMI concomitant with EF and does not increase the risk of hernia recurrence.

Comparison of Surgisis, Vypro II and TiMesh in contaminated and clean field

PURPOSE

The study aimed to evaluate the histologic properties and infection resistance of three different mesh materials in a rat model.

METHODS

Each mesh, in both infectious (n = 96) and non-infectious groups (n = 270), was positioned both in sublay (preperitoneally) and onlay (subcutaneously) locations. Properties of the biological (Surgisis; Cook Surgical), composite, partially resorbing (Vypro II mesh; Ethicon) and non-resorbing (TiMesh; GFE Medizintechnik GmbH) mesh were evaluated and compared. Animals were killed at 7, 21 and 90 days after implantation. The following parameters were evaluated to assess the host response to the mesh material: inflammation, vascularization, fibrosis, collagen formation, Ki67, and a foreign body reaction by granuloma formation (FBG).

RESULTS

Surgisis mesh produced more pronounced inflammation and cell proliferation, and less intense granuloma formation, as well as fibrosis, compared to the other two groups. When the infected materials were examined, we found signs of local infection to be more often present in Surgisis group of animals.

CONCLUSIONS

In the presence of bacterial contamination, no benefits were observed in the use of the Surgisis prosthesis over the use of TiMesh and Vypro II.

Plasmon-Based Biofilm Inhibition on Surgical Implants

The insertion of an implant in the body of a patient raises the risk of a posterior infection and formation of a biofilm, which can have critical consequences on the patient's health and be associated with a high sanitary cost. While antibacterial agents can be used to prevent the infection, such a strategy is time-limited and causes bacteria resistance. As an alternative to biochemical approaches, we propose here to use light-induced local hyperthermia with plasmonic nanoparticles. This strategy is implemented on surgical meshes, extensively used in the context of hernia repairing, one of the most common general surgeries. Surgical meshes were homogeneously coated with gold nanorods designed to efficiently convert near-infrared light into heat. The modified mesh was exposed to a biofilm of Staphylococcus aureus ( S. aureus) bacteria before being treated with a train of light pulses. We systematically study how the illumination parameters, namely fluence, peak intensity and pulse length, influence the elimination of attached bacteria. Additionally, fluorescence confocal microscopy provides us some insight on the mechanism involved in the degradation of the biofilm. This proof-of-principle study opens a new set of opportunities for the development of novel disinfection approaches combining light and nanotechnology.

Chitosan Cross-Linked Bio-based Antimicrobial Polypropylene Meshes for Hernia Repair Loaded with Levofloxacin HCl via Cold Oxygen Plasma

Polypropylene (PP) large pore size nets have been most widely used implants for hernia repair. Nevertheless, the growth of bacteria within PP mesh pores after operation is a major reason of hernia recurrence. Secondly, pre-operative prophylaxis during mesh implantation has failed due to the hydrophobic nature of PP meshes. Herein, chitosan cross-linked and levofloxacin HCl incorporated, antimicrobial PP mesh devices were prepared using citric acid as a bio-based and green cross-linking agent. The inert PP mesh fibers were surface activated using O2 plasma treatment at low pressure. Then, chitosan of different molecular weights (low and medium weight) were cross-linked with O2 plasma activated surfaces using citric acid. Scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, and Fourier transform infrared (FTIR) spectroscopy confirmed that chitosan was cross-linked with O2 plasma-treated PP mesh surfaces and formed a thin layer of chitosan and levofloxacin HCl on the PP mesh surfaces. Moreover, antimicrobial properties of chitosan and levofloxacin HCl-coated PP meshes were investigated using an agar plate release method. The coated PP meshes demonstrated excellent antimicrobial inhibition zone up to 10 mm. Thus, modified PP meshes demonstrated sustained antimicrobial properties for six continuous days against Staphylococcus aureus (SA) and Escherichia coli (EC) bacteria.

Polydopamine-Inspired Surface Modification of Polypropylene Hernia Mesh Devices via Cold Oxygen Plasma: Antibacterial and Drug Release Properties

Mesh infection is a major complication of hernia surgery after polypropylene (PP) mesh implantation. Modifying the PP mesh with antibacterial drugs is an effective way to reduce the chance of infection, but the hydrophobic characteristic of PP fibers has obstructed the drug adhesion. Therefore, to prepare antimicrobial PP mesh with a stable drug coating layer and to slow the drug release property during the hernia repair process has a great practical meaning. In this work, PP meshes were coated by bio-inspired polydopamine (PDA), which can load and release levofloxacin. PP meshes were activated with cold oxygen plasma and then plasma activated PP fibers were coated with PDA. The PDA coated meshes were further soaked in levofloxacin. The levofloxacin loaded PP meshes demonstrate excellent antimicrobial properties for 6 days and the drug release has lasted for at least 24 h. Moreover, a control PP mesh sample without plasma treatment was also prepared, after coating with PDA and loading levofloxacin. The antimicrobial property was sustained only for two days. The maximum inhibition zone of PDA coated meshes with and without plasma treatment was 12.5 and 9 mm, respectively. On all accounts, the modification strategy can facilely lead to long-term property of infection prevention.

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.

One-Step Surface Functionalized Hydrophilic Polypropylene Meshes for Hernia Repair Using Bio-Inspired Polydopamine

An ideal hernia mesh is one that absorbs drugs and withstands muscle forces after mesh implantation. Polypropylene (PP) mesh devices have been accepted as a standard material to repair abdominal hernia, but the hydrophobicity of PP fibers makes them unsuitable to carry drugs during the pre-implantation of PP meshes. In this study, for the first time, one-step functionalization of PP mesh surfaces was performed to incorporate bio-inspired polydopamine (PDA) onto PP surfaces. All PP mesh samples were dipped in the same concentration of dopamine solution. The surface functionalization of PP meshes was performed for 24 h at 37 °C and 80 rpm. It was proved by scanning electron microscopic (SEM) images and Fourier Transform Infrared Spectroscopy (FTIR) results that a thin layer of PDA was connected with PP surfaces. Moreover, water contact angle results proved that surface functionalized PP meshes were highly hydrophilic (73.1°) in comparison to untreated PP mesh surfaces (138.5°). Thus, hydrophilic PP meshes with bio-inspired poly-dopamine functionalization could be a good choice for hernia mesh implantation.

A critical review of the in vitro and in vivo models for the evaluation of anti-infective meshes

BACKGROUND

Infectious complications following mesh implantation for abdominal wall repair appear in 0.7 up to 26.6% of hernia repairs and can have a detrimental impact for the patient. To prevent or to treat mesh-related infection, the scientific community is currently developing a veritable arsenal of antibacterial meshes. The numerous and increasing reports published every year describing new technologies indicate a clear clinical need, and an academic interest in solving this problem. Nevertheless, to really appreciate, to challenge, to compare and to optimize the antibacterial properties of next generation meshes, it is important to know which models are available and to understand them.

PURPOSE

We proposed for the first time, a complete overview focusing only on the in vitro and in vivo models which have been employed specifically in the field of antibacterial meshes for hernia repair.

RESULTS AND CONCLUSION

From this investigation, it is clear that there has been vast progress and breadth in new technologies and models to test them. However, it also shows that standardization or adoption of a more restricted number of models would improve comparability and be a benefit to the field of study.

Systematic review of the stage of innovation of biological mesh for complex or contaminated abdominal wall closure

Background

Achieving stable closure of complex or contaminated abdominal wall incisions remains challenging. This study aimed to characterize the stage of innovation for biological mesh devices used during complex abdominal wall reconstruction and to evaluate the quality of current evidence.

Methods

A systematic review was performed of published and ongoing studies between January 2000 and September 2017. Eligible studies were those where a biological mesh was used to support fascial closure, either prophylactically after midline laparotomy, or for reinforcement after repair of incisional hernia with midline incision. The primary outcome measure was the IDEAL framework stage of innovation. The key secondary outcome measure was the GRADE criteria for study quality.

Results

Thirty‐five studies including 2681 patients were included. Four studies considered mesh prophylaxis, 23 considered hernia repair, and eight reported on both. There was one published randomized trial (IDEAL stage 3), none of which was of high quality; the others were non‐randomized studies (IDEAL stage 2a). A detailed description of surgical technique was provided in most studies (27 of 35); however, no study reported outcomes according to the European Hernia Society consensus statement and only two described quality control of surgical technique during the study. From 21 ongoing randomized trials and observational studies, 11 considered repair of incisional hernia and 10 considered prophylaxis (seven in elective settings).

Conclusion

The evidence base for biological mesh is limited, and better reporting and quality control of surgical techniques are needed. Although results of ongoing trials over the next decade will improve the evidence base, further study is required in the emergency and contaminated settings.

Infections associated with mesh repairs of abdominal wall hernias: Are antimicrobial biomaterials the longed-for solution?

The incidence of mesh-related infection after abdominal wall hernia repair is low, generally between 1 and 4%; however, worldwide, this corresponds to tens of thousands of difficult cases to treat annually. Adopting best practices in prevention is one of the keys to reduce the incidence of mesh-related infection. Once the infection is established, however, only a limited number of options are available that provides an efficient and successful treatment outcome. Over the past few years, there has been a tremendous amount of research dedicated to the functionalization of prosthetic meshes with antimicrobial properties, with some receiving regulatory approval and are currently available for clinical use. In this context, it is important to review the clinical importance of mesh infection, its risk factors, prophylaxis and pathogenicity. In addition, we give an overview of the main functionalization approaches that have been applied on meshes to confer anti-bacterial protection, the respective benefits and limitations, and finally some relevant future directions.

Impact of Surgical Site Infections on Elective Incisional Hernia Surgery: A Prospective Study

BACKGROUND

Although incisional hernia repair is classified as a clean surgery, it still has a high incidence of surgical site infection (SSI) (0.7%-26.6%). The presence of an SSI could increase early recurrence rates after incisional hernia repair.

PATIENTS AND METHODS

Patients undergoing elective incisional hernia repair with no bowel contamination between January and December 2015 were assessed prospectively. Demographic and surgical data, local post-operative complications, and one-year recurrence rates in patients with and without SSI were compared. The management of SSI was determined.

RESULTS

Patients with SSI (16/101) showed more prolonged surgical procedures (91 ± 39 vs. 63 ± 30 min, p = 0.012), more post-operative sero-hematomas (38% vs. 8%, p = 0.001), and a higher one-year recurrence rate (19% vs. 4%, p = 0.047). Multivariable analysis revealed the only identified risk factor for SSI to be post-operative sero-hematomas (p = 0.042; odds ratio [OR] = 4.17 [1.05-16.54]). Patients who developed an SSI required antibiotic agents and daily treatment from one to five months. One of these required the removal of the mesh.

CONCLUSIONS

Surgical site infection rates are high for incisional hernia surgery (16%), and associated with local complications. Surgical site infection requires long-term treatments and leads to a higher one-year recurrence rate.

Myths in peritoneal dialysis

PURPOSE OF REVIEW

To clarify misconceptions about the feasibility and risks of peritoneal dialysis that unnecessarily limit peritoneal dialysis uptake or continuation in patients for whom peritoneal dialysis is the preferred dialysis modality. The inappropriate choice of haemodialysis as a result of these misconceptions contributes to low peritoneal dialysis penetrance, increases transfer from peritoneal dialysis to haemodialysis, increases expenditure on haemodialysis and compromises quality of life for these patients.

RECENT FINDINGS

Peritoneal dialysis is an excellent renal replacement modality that is simple, cost-effective and provides comparable clinical outcomes to conventional in-centre haemodialysis. Unfortunately, many patients are deemed unsuitable to start or continue peritoneal dialysis because of false or inaccurate beliefs about peritoneal dialysis. Here, we examine some of these 'myths' and critically review the evidence for and against each of them. We review the feasibility and risk of peritoneal dialysis in patients with prior surgery, ostomies, obesity and mesh hernia repairs. We examine the fear of mediastinitis with peritoneal dialysis after coronary artery bypass graft surgery and the belief that the use of hypertonic glucose dialysate causes peritoneal membrane failure.

SUMMARY

By clarifying common myths about peritoneal dialysis, we hope to reduce overly cautious practices surrounding this therapy.