Ventral hernia repair in rat using nanofibrous polylactic acid/polypropylene meshes

Self-gripping versus polypropylene mesh for incisional hernia repair in a rat model

BACKGROUND

Self-gripping mesh, made of monofilament polypropylene and covered by a layer of polylactic acid micro-hooks, is applied in ventral hernia repair, whereas cytological change and collagen expression around the mesh are rarely reported. The objective of this research was to compare inflammatory response and collagen proliferation between self-gripping and polypropylene mesh in rat model of incisional hernia.

METHODS

Forty-five rats were randomly divided into unrepaired (UR) group, polypropylene (PP) mesh group, and self-gripping (SG) mesh group and euthanized at 1, 2 and 4 weeks postoperatively. The levels of inflammation, neovascularization, and collagen expression were measured by immunohistochemistry, quantitative real-time polymerase chain reaction, and Western blot.

RESULTS

One rat died and others developed typical incisional hernia in UR group, and hematoma, seroma, or wound infection were not observed in PP and SG groups. There was no significant difference in mesh shrinkage and inflammatory infiltration between PP and SG groups. With regard to neovascularization, 2 groups were comparable at 1 and 2 weeks, while the neovascularization score of PP group was statistically higher than that of SG group at 4 weeks. One week after surgery, the amounts of Collagen I (Col I) mRNA in PP group were significantly higher than SG group, while the amounts of Collagen III (Col III) mRNA were comparable between 2 groups. Two weeks following operation, the expressions of Col I mRNA and Col III mRNA in PP group were statistically lower than those in SG group. Four weeks postoperatively, the levels of Col I mRNA and Col III mRNA in PP group were significantly higher than those in SG group.

CONCLUSION

Self-gripping mesh induced comparable inflammatory response and collagen proliferation compared with polypropylene mesh in a rat model.

REGISTRATION NUMBER

ZZU-LAC2023080121.

Coatings for Permanent Meshes Used to Enhance Healing in Abdominal Hernia Repair: A Scoping Review

INTRODUCTION

Hernia meshes are used to reduce recurrence and pain rates, but the rates are still high. This could be improved with coatings of the mesh. This scoping review aimed to provide an overview of mesh coatings used to promote healing in abdominal hernia repair and to report beneficial and unbeneficial effects.

METHODS

We included human and animal studies with abdominal hernias that were repaired with non-commercially coated meshes. We searched Pubmed, Embase, Cochrane Central, LILACS, and CNKI without language constraints.

RESULTS

Of 2933 identified studies, 58 were included: six studies had a total of 408 humans and 52 studies had 2679 animals. The median follow-up was 12 months (range 1-156), and 95% of the hernias were incisional. There were 44 different coatings which included platelet-rich plasma, mesenchymal stem cells, growth factors, vitamin E, collagen-derived products, various polysaccharides, silk proteins, chitosan, gentamycin, doxycycline, nitrofurantoin, titanium, and diamond-like carbon. Mesenchymal stem cells and platelet-rich plasma were the most researched. Mesenchymal stem cells notably reduced inflammation and foreign body reactions but did not impact other healing metrics. In contrast, platelet-rich plasma positively influenced tissue ingrowth, collagen deposition, and neovascularization and had varying effects on inflammation and foreign body reactions.

CONCLUSION

We identified 44 different mesh coatings and they showed varying results. Mesenchymal stem cells and platelet-rich plasma were the most studied, with the latter showing considerable promise in improving biomechanical properties in hernia repair. Further investigations are needed to ascertain their definitive use in humans.

Polyurethane-based three-dimensional printing for biological mesh carriers

Repair and reconstruction of the myopectineal orifice area using meshes is the mainstay of surgical treatment of inguinal hernias. However, the limitations of existing meshes are becoming increasingly evident in clinical applications; thus, the idea of using three-dimensionally (3D)-printed biological meshes was put forward. According to the current level of the 3D printing technology and the inherent characteristics of biological materials, the direct use of the 3D printing technology for making biological materials into finished products suitable for clinical applications is not yet supported, but synthetic materials can be first printed into 3D form carriers, compounded with biological materials, and finally made into finished products. The purpose of this study was to develop a technical protocol for making 3D-printed biomesh carriers using polyurethane as a raw material. In our study: raw material, polyurethane; weight, 20-30 g/m2; weaving method, hexagonal mesh; elastic tension aspect ratio, 2:1; diameters of pores, 0.1-1 mm; surface area, 8 × 12 cm2; the optimal printing layer height, temperature and velocity were 0.1 mm, 210-220 °C and 60 mm/s. Its clinical significance lies in: (1) applied to preoperative planning and design a detailed surgical plan; (2) applied to special types of surgery including patients in puberty, recurrent and compound inguinal hernias; (3) significantly improve the efficiency of doctor-patient communication; (4) it can shorten the operation and recovery period by about 1/3 and can save about 1/4 of the cost for patients; (5) the learning curve is significantly shortened, which is conducive to the cultivation of reserve talents.

A novel electrospun polylactic acid silkworm fibroin mesh for abdominal wall hernia repair

Objective

Abdominal wall hernias are common abdominal diseases, and effective hernia repair is challenging. In clinical practice, synthetic meshes are widely applied for repairing abdominal wall hernias. However, postoperative complications, such as inflammation and adhesion, are prevalent. Although biological meshes can solve this problem to a certain extent, they face the problems of heterogeneity, rapid degradation rate, ordinary mechanical properties, and high-cost. Here, a novel electrospinning mesh composed of polylactic acid and silk fibroin (PLA-SF) for repairing abdominal wall hernias was manufactured with good physical properties, biocompatibility and low production cost.

Materials and methods

FTIR and EDS were used to demonstrate that the PLA-SF mesh was successfully synthesized. The physicochemical properties of PLA-SF were detected by swelling experiments and in vitro degradation experiments. The water contact angle reflected the hydrophilicity, and the stress‒strain curve reflected the mechanical properties. A rat abdominal wall hernia model was established to observe degradation, adhesion, and inflammation in vivo. In vitro cell mesh culture experiments were used to detect cytocompatibility and search for affected biochemical pathways.

Results

The PLA-SF mesh was successfully synthesized and did not swell or degrade over time in vitro. It had a high hydrophilicity and strength. The PLA-SF mesh significantly reduced abdominal inflammation and inhibited adhesion formation in rat models. The in vitro degradation rate of the PLA-SF mesh was slower than that of tissue remodeling. Coculture experiments suggested that the PLA-SF mesh reduced the expression of inflammatory factors secreted by fibroblasts and promoted fibroblast proliferation through the TGF-β1/Smad pathway.

Conclusion

The PLA-SF mesh had excellent physicochemical properties and biocompatibility, promoted hernia repair of the rat abdominal wall, and reduced postoperative inflammation and adhesion. It is a promising mesh and has potential for clinical application.

Abdominal wall hernia repair: from prosthetic meshes to smart materials

Hernia reconstruction is one of the most frequently practiced surgical procedures worldwide. Plastic surgery plays a pivotal role in reestablishing desired abdominal wall structure and function without the drawbacks traditionally associated with general surgery as excessive tension, postoperative pain, poor repair outcomes, and frequent recurrence. Surgical meshes have been the preferential choice for abdominal wall hernia repair to achieve the physical integrity and equivalent components of musculofascial layers. Despite the relevant progress in recent years, there are still unsolved challenges in surgical mesh design and complication settlement. This review provides a systemic summary of the hernia surgical mesh development deeply related to abdominal wall hernia pathology and classification. Commercial meshes, the first-generation prosthetic materials, and the most commonly used repair materials in the clinic are described in detail, addressing constrain side effects and rational strategies to establish characteristics of ideal hernia repair meshes. The engineered prosthetics are defined as a transit to the biomimetic smart hernia repair scaffolds with specific advantages and disadvantages, including hydrogel scaffolds, electrospinning membranes, and three-dimensional patches. Lastly, this review critically outlines the future research direction for successful hernia repair solutions by combing state-of-the-art techniques and materials.

Polypropylene mesh combined with electrospun poly (L-lactic acid) membrane in situ releasing sirolimus and its anti-adhesion efficiency in rat hernia repair

This study developed, a novel polypropylene (PP) mesh combined with poly (L-lactic acid) (PLA) electrospun nanofibers loaded sirolimus (SRL). The PP mesh was combined with PLA/SRL (1/0, 1/0.01, 1/0.02; mass ratios) composed electrospun membrane characterized by FTIR spectroscopy, XPS and SEM, and evaluated for cytocompatibility in vitro. In an in vivo study, a total of 84 Sprague-Dawley rats were employed to evaluate the efficacy of the novel composite PP mesh anti-adhesion, mechanical properties and inflammation. As a results, the PLA/SRL membrane could compound with PP mesh stably and load SRL. Although tensile testing showed that the mechanical properties of composite mesh decreased in vivo, the integration strength between the tissue and mesh was still able to counteract intra-abdominal pressure. Compared with the native PP mesh group, the novel PP mesh group showed a lower score for abdominal adhesion and inflammation. More importantly, the novel PP mesh completely integrated with the abdominal wall and had sufficient mechanical strength to repair abdominal wall defects.

The Synthetic Scaffolds for Ventral Hernia Repair: Perspectives for Regenerative Surgery—Systematic Review

Ventral hernia (VH) frequently affects patients after abdominal surgery. The use of a mesh is often recommended. Different materials are described, from synthetic non-resorbable meshes to biological meshes. New generation meshes, also named scaffolds, aim to combine the advantages of both materials. The aim of this review is to provide an overview of the cytological, histological, biomechanical, and clinical outcomes of the use of the newest resorbable synthetic scaffolds in VH repair, based on experimental studies in a pre-clinical setting. A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and to the Assessing the Methodological Quality of Systematic Reviews (AMSTAR) guidelines. Only experimental studies were included. Outcome parameters were building technique, in vitro cytocompatibility, in vivo histocompatibility, biomechanical analysis, and clinical outcomes. The articles included were nine. The total number of cases treated was 257. Materials analyzed included electrospun silk fibroin (SF)/poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) hybrid scaffolds, biodegradable polyester poly-ε-caprolactone (PCL) in the form of nanofibers, biodegradable mesh in poly-4-hydroxybutyrate (P4HB), nanofibrous polylactic acid (PLA) scaffold with a polypropylene (PP) material to generate a sandwich-like mesh, the collagen sponge (CS) group, the hybrid scaffold (HS) containing CS and poly-L-lactide (PLLA), and the hybrid scaffold (HS) + bone marrow (HSBM). Resorbable synthetic scaffolds are new, safe, surgical materials for the treatment or prevention of ventral hernia in animal models. Scaffolds should be tested in a contaminated surgical field for emergency use. Rigorous schematic indications for data collection are needed to improve the quality of the data in order to definitively clarify the pathway involved in inflammatory induced response.

New Insights into the Application of 3D-Printing Technology in Hernia Repair

Abdominal hernia repair using prosthetic materials is among the surgical interventions most widely performed worldwide. These materials, or meshes, are implanted to close the hernial defect, reinforcing the abdominal muscles and reestablishing mechanical functionality of the wall. Meshes for hernia repair are made of synthetic or biological materials exhibiting multiple shapes and configurations. Despite the myriad of devices currently marketed, the search for the ideal mesh continues as, thus far, no device offers optimal tissue repair and restored mechanical performance while minimizing postoperative complications. Additive manufacturing, or 3D-printing, has great potential for biomedical applications. Over the years, different biomaterials with advanced features have been successfully manufactured via 3D-printing for the repair of hard and soft tissues. This technological improvement is of high clinical relevance and paves the way to produce next-generation devices tailored to suit each individual patient. This review focuses on the state of the art and applications of 3D-printing technology for the manufacture of synthetic meshes. We highlight the latest approaches aimed at developing improved bioactive materials (e.g., optimizing antibacterial performance, drug release, or device opacity for contrast imaging). Challenges, limitations, and future perspectives are discussed, offering a comprehensive scenario for the applicability of 3D-printing in hernia repair.

Topological Structure Design and Fabrication of Biocompatible PLA/TPU/ADM Mesh with Appropriate Elasticity for Hernia Repair

The meshes for hernia repair result in many problems that are related to complications including chronic pain and limited movement due to inadequate mechanical strength, non-absorbability, or low elasticity. In this study, degradable polylactic acid (PLA), synthetic thermoplastic polyurethane (TPU), and acellular dermal matrix (ADM) powders are combined to prepare a novel PLA/TPU/ADM mesh with three different topological structures (square, circular, and diamond) by 3D printing. The physicochemical properties and structural characteristics of mesh are studied, the results show that the diamond structure mesh with the pore size of 3 mm has sufficient elasticity and tensile strength, which provides the efficient mechanical strength required for hernia repair (16 N cm^-1 ) and the value more than polypropylene(PP) mesh. Besides, in vitro and in vivo experiments demonstrate human umbilical vein endothelial cells could successfully proliferate on the PLA/TPU/ADM mesh whose biocompatibility with the host is shown using a rat model of abdominal wall defect. In conclusion, the results of this study demonstrate that the PLA/TPU/ADM mesh may be considered a good choice for hernia repair as its potential to overcome the elastic and strength challenges associated with a highly flexible abdominal wall, as well as its good biocompatibility.

Regenerated silk fibroin (RSF) electrostatic spun fibre composite with polypropylene mesh for reconstruction of abdominal wall defects in a rat model

Abdominal wall defects are associated with abdominal wall surgery, infection and tumour resection. Polypropylene (PP) mesh, which has excellent mechanical strength, is currently the primary clinical repair material. In repairing the abdominal wall, the mesh can erode the bowel and cause other problems. Constructing a barrier that induces a weak inflammatory response and promotes rapid recovery of the peritoneum is important. We used electrospinning technology to construct a silk fibroin coating on the abdominal surface of a PP patch. A rat model was used to compare the inflammatory responses, regeneration of peritoneal tissue, and antiadhesion effects of electrospun regenerated silk fibroin (RSF) coatings, polycaprolactone (PCL) coatings, and noncoated PP meshes. The inflammatory responses, antiadhesion fractions, and areas of RSF and PCL were better than those of PP at 6 weeks. RSF was associated with complete peritoneal regeneration, in contrast to PCL. At 12 weeks, the structure of the PCL peritoneum was unstable, and the adhesion fraction and area were significantly higher than those of RSF. The intact peritoneum could not be effectively regenerated. The RSF group exhibited lower IL-6 levels than the PCL and PP groups but higher VEGF, IL-10 and TGF-β levels, making RSF more conducive to the regeneration of peritoneal and abdominal wall tissues.

A new semiresorbable mesh for primary inguinal repair: a preliminary observational study on quality of life and safety

BACKGROUND

A currently unsolved problem of open inguinal hernia repair (IHR) is chronic postoperative inguinal pain (CPIP), which affects 10-12% of patients after IHR. In the present paper, we explored the results of a newly designed partially absorbable mesh made of polypropylene and polylactic acid (HybridMesh®) for open hernia repair and its impact on postoperative safety, efficacy, comfort and pain.

METHODS

A prospective multicentric pilot trial was conducted in third-referral centers across Italy (n = 5). Inclusion criteria were unilateral primary inguinal hernia in patients of both genders and BMI < 30 kg/m2. All patients were submitted to elective Lichtenstein mesh hernia repair under local anesthesia with HybridMesh. Primary outcome measure was the evaluation of Carolina Comfort Scale and modifications at 2 years after surgery and its correlation with surgical variables; secondary outcomes were postoperative early and late morbidity, recurrence and postoperative early quality of life.

RESULTS

Between 2015 and 2016, 125 (5 female) patients were operated, 2-year follow-up rate was 100%. The surgical site occurrence rate was 28% without the need of procedural interventions. Twenty-four months after surgery, no case of severe CPIP was recorded and altered global CCS score was present in 16 patients (13.0%). At univariate analysis, CCS score was negatively affected by fixation with sutures (OR 3.949; 95% CI 1.334-13.300), with no effect shown on multivariate analysis. Alterations in pain and movement limitations domains of CCS were observed in 9.7% of patients, at univariate analysis; they occurred more frequently when the mesh was sutured (OR 4.437; 95% CI 1.387-17.025) and in patients suffering from SSO (ecchymosis: OR 3.269; 95% CI 1.032-10.405); however, no effect was shown on multivariate analysis. Two recurrences (1.6%) were identified within the first postoperative year.

CONCLUSIONS

The results of this study support the safety, efficacy and good tolerability of HybridMesh as a device to treat primary unilateral inguinal hernia during open anterior approach. Further studies are needed to clarify its role in comparison to currently available devices at longer follow-ups.

Combination of Polypropylene Mesh and in Situ Injectable Mussel-Inspired Hydrogel in Laparoscopic Hernia Repair for Preventing Post-Surgical Adhesions in the Piglet Model

Polypropylene (PP) mesh has been used successfully for a long time in clinical practice as an impressive prosthesis for ventral hernia repair. To utilize a physical barrier for separating mesh from viscera is a general approach for preventing adhesions in clinical practice. However, a serious abdominal adhesion between the mesh and viscera can possibly occur post-hernia, especially with the small intestine; this can lead to a series of complications, such as chronic pain, intestinal obstruction, and fistula. Thus, determining how to prevent abdominal adhesions between the mesh and viscera is still an urgent clinical problem. In this study, a dopamine-functionalized polysaccharide derivative (oxidized-carboxymethylcellulose-g-dopamine, OCMC-DA) was synthesized; this was blended with carboxymethylchitosan (CMCS) to form a hydrogel (OCMC-DA/CMCS) in situ at the appropriate time. The physical and chemical properties of the hydrogel were characterized successfully, and its excellent biocompatibility was presented by the in vitro cell test. The combination of this hydrogel and PP mesh was used in laparoscopic surgery for repairing the abdominal wall defect, where the hydrogel could become fixed in situ on the PP mesh to form an anti-adhesion gel-mesh. The results showed that the gel-mesh could prevent abdominal adhesions effectively in the piglet model. Moreover, the histology and immunohistochemical staining proved that the gel-mesh could effectively alleviate the inflammation reaction and deposition of collagen around the mesh, and it did not disturb the integration between mesh and abdominal wall. Thus, the gel-mesh has superior tissue compatibility.

Design of a new dual mesh with an absorbable nanofiber layer as a potential implant for abdominal hernia treatment

Dual meshes are often preferred in the treatment of umbilical and incisional hernias where the abdominal wall defect is large. These meshes are generally composed of either two nonabsorbable layers or a nonabsorbable layer combined with an absorbable one that degrades within the body upon healing of the defect. The most crucial point in the design of a dual mesh is to produce the respective layers based on the structure and requirements of the recipient site. We herein developed a dual mesh that consists of two layers: a nanofibrous layer made of poly (glycerol sebacate)/poly (caprolactone) (PGS/PCL) to support the healing of the abdominal wall defect and a nondegradable, nonadhesive smooth layer made of polycarbonateurethane (PU) with suitable properties to avoid the adhesion of the viscera to the mesh. To prepare the double-sided structure, PGS/PCL was directly electrospun onto the PU film. This processing approach provided a final product with well-integrated layers as observed by a scanning electron microscope. Tensile test performed at the dry state of the samples showed that the dual mesh has the ability to elongate seven times more as compared with the commercially available counterparts, mimicking the native tissue properties. The degradation test carried out at physiological conditions revealed that PGS started to degrade within the first 15 days. in vitro studies with human umbilical vein endothelial cells demonstrated the double function of the meshes, in which PU layer did not allow cell adhesion, whereas PGS/PCL layer has the ability to support cell adhesion and proliferation. Therefore, the material developed in this study has the potential to be an alternative to the existing hernia mesh products.