Searching for the best polypropylene mesh to be used in bowel contamination

If laparoscopic technique can be used for treatment of acutely incarcerated/strangulated inguinal hernia?

Purpose

Laparoscopic treatment for acutely incarcerated/strangulated inguinal hernias is uncommon and controversial. In the present study, we assessed the safety and feasibility of transabdominal preperitoneal (TAPP) repair for the treatment of acutely incarcerated/strangulated inguinal hernias.

Methods

Patients with acutely incarcerated/strangulated inguinal hernias who underwent TAPP repair at the Department of Hernia and Abdominal Wall Surgery (Beijing Chaoyang Hospital) from January 2017 to December 2019 were retrospectively reviewed. Patients’ characteristics, operation details, and postoperative complications were retrospectively analyzed.

Results

In total, 94 patients with acutely incarcerated/strangulated inguinal hernias underwent TAPP repair. The patients comprised 85 men and 9 women (mean age, 54.3 ± 13.6 years; mean operating time, 61.6 ± 17.7 min; mean hospital stay, 3.9 ± 2.2 days). No patients were converted to open surgery. Hernia reduction was successfully performed in all patients. The morbidity of complications was 20.2% (19/94). Two bowel resections were performed endoscopically. Nine (9.6%) patients avoided unnecessary bowel resections during laparoscopic procedures. All patients recovered well without severe complications. No recurrence or infection was recorded during a mean follow-up period of 26.8 ± 9.8 months.

Conclusions

TAPP appears to be safe and feasible for treatment of patients with acutely incarcerated/strangulated inguinal hernias. However, it requires performed by experienced surgeons in laparoscopic techniques.

Biological Mesh in Contaminated Fields—Overuse without Data: A Systematic Review of Their Use in Abdominal Wall Reconstruction

Ventral hernia repair in contaminated fields is a significant problem for surgeons. We performed a systematic review regarding the use of biological mesh in contaminated fields for abdominal wall reconstruction. The primary end points were recurrence and infection of the hernia repair. An independent search of scientific papers in the English language was performed by three reviewers. Articles were chosen based on reference to ventral hernias, their use in infected fields, and in human subjects. Papers were scored using the Methodological Index for Non-Randomized Studies and those with a score of 8 or more were combined to evaluate the end points. A total of 16 studies from six different mesh products met our criteria. These papers comprised 554 patients with an overall infection rate of 24 per cent and a recurrence rate of 20 per cent. The largest study used 116 patients. All papers were case series. Overall the data for use of biological mesh products in contaminated fields are limited. Further controlled studies are needed to address this important and clinically relevant question. Caution should be used when using biological mesh products in infected fields because there is a paucity of controlled data and none have U.S. Food and Drug Administration approval for use in infected fields.

Fabrication and Characterization of Composite Meshes Loaded with Antimicrobial Peptides

Biomaterials-centered infection or implant-associated infection plays critical roles in all areas of medicine with implantable devices. The widespread over use of antibiotics has caused severe bacterial resistance and even super bugs. Therefore, the development of anti-infection implantable devices with non-antibiotic-based new antimicrobial agents is indeed a priority for all of us. In this study, antimicrobial composite meshes were fabricated with broad-spectrum antimicrobial peptides (AMPs). Macroporous polypropylene meshes with poly-caprolactone electrospun nanosheets were utilized as a substrate to load AMPs and gellan gum presented as a media to gel with AMPs. Different amounts of AMPs were loaded onto gellan gum to determine the appropriate dose. The surface morphologies, Fourier-transform infrared spectroscopy spectra, in vitro release profiles, mechanical performances, in vitro antimicrobial properties, and cytocompatibility of composite scaffolds were evaluated. Results showed that AMPs were loaded into the meshes successfully, the in vitro release of AMPs in phosphate-buffered saline was prolonged, and less than 60% peptides were released in 10 days. The mechanical properties of composite meshes were also within the scope of several commercial surgical meshes. Composite meshes with the AMP loading amount of over 3 mg/cm² showed inhibition against both Gram-negative and Gram-positive bacteria effectively, while they presented no toxicity to mammalian cells even at a loading amount of 10 mg/cm². These results demonstrate a new simple and practicable method to offer antimicrobial properties to medical devices for hernia repair.

Fight or Flight: The Role of Staged Approaches to Complex Abdominal Wall Reconstruction

Surgeons' comfort with abdominal wall reconstruction techniques and use of prosthetic reinforcement in contaminated fields has made repair of complex hernias during concomitant procedures an attractive endeavor. Understanding the precarious nature of this practice, tenets of thoughtful patient selection, and principles of repair that mitigate morbidity can allow for an educated thought process when deciding whether or not to pursue concomitant abdominal wall reconstruction.

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.

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.

In vivo response to polypropylene following implantation in animal models: a review of biocompatibility

INTRODUCTION AND HYPOTHESIS

Polypropylene is a material that is commonly used to treat pelvic floor conditions such as pelvic organ prolapse (POP) and stress urinary incontinence (SUI). Owing to the nature of complications experienced by some patients implanted with either incontinence or prolapse meshes, the biocompatibility of polypropylene has recently been questioned. This literature review considers the in vivo response to polypropylene following implantation in animal models. The specific areas explored in this review are material selection, impact of anatomical location, and the structure, weight and size of polypropylene mesh types.

METHODS

All relevant abstracts from original articles investigating the host response of mesh in vivo were reviewed. Papers were obtained and categorised into various mesh material types: polypropylene, polypropylene composites, and other synthetic and biologically derived mesh.

RESULTS

Polypropylene mesh fared well in comparison with other material types in terms of host response. It was found that a lightweight, large-pore mesh is the most appropriate structure.

CONCLUSION

The evidence reviewed shows that polypropylene evokes a less inflammatory or similar host response when compared with other materials used in mesh devices.

Mesh Infection and Hernia Repair: A Review

BACKGROUND

The use of a prosthetic mesh to repair a tissue defect may produce a series of post-operative complications, among which infection is the most feared and one of the most devastating. When occurring, bacterial adherence and biofilm formation on the mesh surface affect the implant's tissue integration and host tissue regeneration, making preventive measures to control prosthetic infection a major goal of prosthetic mesh improvement.

METHODS

This article reviews the literature on the infection of prosthetic meshes used in hernia repair to describe the in vitro and in vivo models used to examine bacterial adherence and biofilm formation on the surface of different biomaterials. Also discussed are the prophylactic measures used to control implant infection ranging from meshes soaked in antibiotics to mesh coatings that release antimicrobial agents in a controlled manner.

RESULTS

Prosthetic architecture has a direct effect on bacterial adherence and biofilm formation. Absorbable synthetic materials are more prone to bacterial colonization than non-absorbable materials. The reported behavior of collagen biomeshes, also called xenografts, in a contaminated environment has been contradictory, and their use in this setting needs further clinical investigation. New prophylactic mesh designs include surface modifications with an anti-adhesive substance or pre-treatment with antibacterial agents or metal coatings.

CONCLUSIONS

The use of polymer coatings that slowly release non-antibiotic drugs seems to be a good strategy to prevent implant contamination and reduce the onset of resistant bacterial strains. Even though the prophylactic designs described in this review are mainly focused on hernia repair meshes, these strategies can be extrapolated to other implantable devices, regardless of their design, shape or dimension.

Delayed primary closure of contaminated abdominal wall defects with non-crosslinked porcine acellular dermal matrix compared with conventional staged repair: a retrospective study

INTRODUCTION

Synthetic mesh has been used traditionally to repair abdominal wall defects, but its use is limited in the case of bacterial contamination. New biological materials are now being used successfully for delayed primary closure of contaminated abdominal wall defects. The costs of biological materials may prevent surgeons from using them. We compared the conventional staged repair of contaminated abdominal wall defects with a single-stage procedure using a non-crosslinked porcine acellular dermal matrix.

METHODS

A total of 14 cases with Grade 3 contaminated abdominal wall defects underwent delayed primary closure of the abdomen using a non-crosslinked porcine acellular dermal matrix (Strattice™ Reconstructive Tissue Matrix, LifeCell Corp., Branchburg, NJ, USA). The results were compared with a group of 14 patients who had received conventional treatment for the repair of contaminated abdominal wall defects comprising a staged repair during two separate hospital admissions employing synthetic mesh. Treatment modalities, outcomes, and costs were compared.

RESULTS

In all cases treated with delayed primary closure employing non-crosslinked porcine acellular dermal matrix, there were no complications related to its use. Two patients died due to unrelated events. Although treatment costs were estimated to be similar in the two groups, the patients treated with porcine acellular dermal matrix spent less time as an inpatient than those receiving conventional two-stage repair.

CONCLUSIONS

Delayed primary closure of contaminated abdominal wall defects using a non-crosslinked porcine acellular dermal matrix may be a suitable alternative to conventional staged repair. In our patients, it resulted in early restoration of abdominal wall function and shorter hospitalization. The costs for treating contaminated abdominal wall defects using porcine acellular dermal matrix during a single hospital admission were not higher than costs for conventional two-stage repair. Further randomized studies are needed to expand upon these findings.

A 5-year clinical experience with single-staged repairs of infected and contaminated abdominal wall defects utilizing biologic mesh

OBJECTIVE

Our objective was to evaluate the safety and durability of biologic mesh for single-staged reconstruction of contaminated fields.

INTRODUCTION

The presence of contamination during ventral hernia repair (VHR) poses a significant challenge. Some advocate for a multistaged reconstructive approach with delayed definitive repair, whereas others perform definitive repair at the initial operation.

METHODS

Patients undergoing single-staged VHR in a contaminated field with biologic mesh over a 5-year period were retrospectively reviewed from a prospectively maintained database. Outcome measures included wound complication and hernia recurrence.

RESULTS

A total of 128 patients (76 F, 52 M) were identified, with a mean age of 58.2 years, mean American Society of Anesthesiologist (ASA) score 3.1, and mean body mass index (BMI) 34.1 ± 9.7 kg/m2. Comorbidities included COPD (n = 29), diabetes (n = 65), smoking (n = 29), and immunosuppression (n = 8). Mean hernia defect size was 431 cm2 (range 40-2450 cm2). Reasons for contamination included the presence of infected mesh (n = 45), stoma (n = 24), concomitant gastrointestinal (GI) surgery (n = 17), enterocutaneous fistula (n = 25), open nonhealing wound(s) (n = 6), enterotomy/colotomy (n = 5), and chronic draining sinus (n = 6). Postoperative wound complications were identified in 61 (47.7%) patients. Predictors of wound complications included ASA score, diabetes, smoking, number of previous abdominal surgeries or hernia repairs, hernia defect size, and operative time. With a mean follow-up time of 21.7 months, hernia recurrence was identified in 40 (31.3%) patients. The majority of recurrent hernias were asymptomatic and 7 patients underwent repair.

CONCLUSIONS

Despite the high rate of wound morbidity associated with single-staged reconstruction of contaminated fields, it can safely be performed with biologic mesh reinforcement. Although biologic mesh in these situations is safe, the long-term durability seems to be less favorable.

Does presoaking synthetic mesh in antibiotic solution reduce mesh infections? An experimental study

BACKGROUND

Prosthetic mesh infection is one of the most challenging complications after hernia repair. We evaluate the efficacy of soaking mesh in antibiotics to prevent prosthetic infection in an animal model of clean-contaminated ventral hernia repair (VHR).

MATERIAL AND METHODS

Rats underwent an acute VHR with one of four synthetic meshes (composite multifilament polyester (Parietex PCO), multifilament polyester (Parietex TET), composite monofilament polypropylene (Ventralight), or monofilament polypropylene (SoftMesh)). Prior to implantation, mesh was soaked in saline or 10 mg/ml of vancomycin for 15 min. Following implantation, meshes were contaminated with 10(4) CFU of methicillin-resistant Staphylococcus aureus (MRSA) bacteria. Thirty days after implantation, mesh samples were cultured and evaluated under scanning electron microscope for biofilm formation.

RESULTS

Presoaking meshes significantly improves bacterial clearance in composite meshes and multifilament polyester mesh. MRSA clearance was as follows for all meshes (saline-soaked vs. vanco-soaked): Parietex PCO (0 vs. 56 %, p = 0.006), Parietex TET (0 vs. 50 %, p = 0.01), Ventralight (20 vs. 78 %, p = 0.012), and SoftMesh (70 vs. 80 %, p = 0.6). MRSA biofilm formation was consistent with bacterial growth.

CONCLUSION

Presoaking multifilament and composite mesh in vancomycin solution reduces MRSA bacterial growth. Its implementation may reduce the risk of mesh infection in clean-contaminated cases, although further investigation with human trials should be performed.

Comparative study of shrinkage, inflammatory response and fibroplasia in heavyweight and lightweight meshes

PURPOSE

In this manuscript, the authors describe an animal study comparing shrinkage, inflammatory response and fibroplasia in heavyweight (HW-PP) and lightweight polypropylene (LW-PP) meshes.

METHODS

Both meshes were fixed on abdominal fascia of 25 Wistar rats (epifascial onlay placement). They were killed at 7, 28 and 90 days to measure the prostheses. Histological analysis was performed with hematoxylin-eosin for cellular counting and immunohistochemistry to measure collagen types I and III.

RESULTS

The authors found that the LW-PP mesh presented greater median shrinkage than HW-PP mesh at 7 (P = .036), 28 (P = .674) and 90 days (P = .038) postoperatively. There were more neutrophils on LW-PP mesh (P = .008) at 7 days, gradually diminishing in both prostheses. Lymphocytes were similar between the implants at 7 days, diminishing about 50 % on LW-PP mesh (P < .001) at 90 days. Macrophages and giant cells diminished on LW-PP and increased on HW-PP meshes (P < .001). Collagen I/III ratio presented a progressive, almost fivefold rise at 90 days, on both mesh types (P < .001). The collagen I/III ratio was similar between LW-PP and HW-PP meshes at the three times studied.

CONCLUSIONS

It is concluded that LW-PP showed more shrinkage than HW-PP mesh at 7 and 90 days, despite the fact that HW-PP presented more lately foreign body reaction. The collagen I/III ratio was similar between the prostheses and increased during the postimplant period.