Polypropylene meshes to prevent abdominal herniation. Can stable coatings prevent adhesions in the long term?

Infection-Resistant Polypropylene Hernia Mesh: Vision & Innovations

The surgical repair of hernias, a prevalent condition affecting millions worldwide, has traditionally relied on polypropylene (PP) mesh due to its favorable mechanical properties and biocompatibility. However, postoperative infections remain a significant complication, underscoring the need for the development of infection-resistant hernia meshes. This study provides a comprehensive analysis of current advancements and innovative strategies aimed at enhancing the infection resistance of PP mesh. It presents an overview of various research efforts focused on the integration of antimicrobial agents, surface modifications, and the development of bioactive coatings to prevent bacterial colonization and biofilm formation. Additionally, the synergistic effects of novel material designs and the role of nanotechnology in optimizing the anti-infective properties of PP mesh are explored. Recent clinical outcomes and in vitro studies are critically examined, highlighting challenges and potential future directions in the development of next-generation hernia meshes. Emphasis is placed on the importance of interdisciplinary approaches in advancing surgical materials with the ultimate goal of improving patient outcomes in hernia repair.

Electrospun meshes for abdominal wall hernia repair: Potential and challenges

Surgical meshes are widely used in abdominal wall hernia repairs. However, consensus on mesh treatment remains elusive due to varying repair outcomes, especially with the introduction of new meshes, posing a substantial challenge for surgeons. Addressing these issues requires communicating the features of emerging candidates with a focus on clinical considerations. Electrospinning is a versatile technique for producing meshes with biomechanical architectures that closely mimic the extracellular matrix and enable incorporation of bioactive and therapeutic agents into the interconnective porous network, providing a favorable milieu for tissue integration and remodeling. Although this promising technique has drawn considerable interest in mesh fabrication and functionalization, currently developed electrospun meshes have limitations in meeting clinical requirements for hernia repair. This review summarizes the advantages and limitations of meshes prepared through electrospinning based on biomechanical, biocompatible, and bioactive properties/functions, offering interdisciplinary insights into challenges and future directions toward clinical mesh-aided hernia repair. STATEMENT OF SIGNIFICANCE: Consensus for hernia treatments using surgical meshes remains elusive based on varying repair outcomes, presenting significant challenges for researchers and surgeons. Differences in understanding mesh between specialists, particularly regarding material characteristics and clinical requirements, contribute to this issue. Electrospinning has been increasingly applied in mesh preparation through various approaches and strategies, aiming to improve abdominal wall hernia by restoring mechanical, morphological and functional integrity. However, there is no comprehensive overview of these emerging meshes regarding their features, functions, and clinical potentials, emphasizing the necessity of interdisciplinary discussions on this topic that build upon recent developments in electrospun mesh and provide insights from clinically practical prospectives.

The Unfulfilled Potential of Synthetic and Biological Hydrogel Membranes in the Treatment of Abdominal Hernias

Hydrogel membranes can offer a cutting-edge solution for abdominal hernia treatment. By combining favorable mechanical parameters, tissue integration, and the potential for targeted drug delivery, hydrogels are a promising alternative therapeutic option. The current review examines the application of hydrogel materials composed of synthetic and biological polymers, such as polyethylene glycol (PEG), polyvinyl alcohol (PVA), gelatine, and silk fibroin, in the context of hernia repair. Overall, this review highlights the current issues and prospects of hydrogel membranes as viable alternatives to the conventional hernia meshes. The emphasis is placed on the applicability of these hydrogels as components of bilayer systems and standalone materials. According to our research, hydrogel membranes exhibit several advantageous features relevant to hernia repair, such as a controlled inflammatory reaction, tissue integration, anti-adhesive-, and even thermoresponsive properties. Nevertheless, despite significant advancements in material science, the potential of hydrogel membranes seems neglected. Bilayer constructs have not transitioned to clinical trials, whereas standalone membranes seem unreliable due to the lack of comprehensive mechanical characterization and long-term in vivo experiments.

Combined use of composite mesh and acellular dermal matrix graft for abdominal wall repair following tumour resection

BACKGROUND

Surgeries for sarcomas in the abdominal wall require wide resections, often radical en bloc resections, which generate major defects involving a very complex repair. The combined use of porcine dermal xenografts, together with composite meshes, may assist in the repair of these defects with minimal complications.

METHOD

We present a series of 19 patients (10 males and 9 females), with a mean age of 53.2 years (range: 11-86 years) treated in the Sarcoma Unit of the Virgen de la Arrixaca University Hospital from January 2015 to December 2021. Histopathologically, there were four chondrosarcomas (21%), three Ewing sarcomas (15.7%), two desmoid tumours (10.5%), two undifferentiated pleomorphic sarcomas (10.5%), two well-differentiated liposarcomas (10.5%), two leiomyosarcomas (10.5%), one synovial sarcoma, one dermatofibrosarcoma protuberans, one fibromyxoid sarcoma (or Evans tumour), and one metastasis from an adenocarcinoma of unknown origin. All the patients were resected following surgical oncology principles and reconstructed by means of the combined use of a composite mesh acting as a neoperitoneum and a porcine dermal xenograft acting as an abdominal neofascia.

RESULTS

The mean size of the defects generated after surgery for tumour excision was 262.8 cm2 (range: 150-600 cm2). After a mean follow-up of 38 months, six patients (31.5%) developed complications-two cases of wound dehiscence, one case of surgical wound infection, one case of graft partial necrosis, one case of anastomotic leak and one death due to multiorgan failure secondary to massive bronchoaspiration.

CONCLUSION

Surgeries for sarcomas of the abdominal wall require wide oncological resections, which generate major abdominal wall defects. The repair of these defects by means of the combined use of synthetic and biological meshes is a technique associated with minimal complications and excellent medium-term results.

Effects of different mesh materials on complications after prophylactic placement for stoma formation: a systematic review and network meta-analysis

PURPOSE

We primary aimed to synthesise the available data, assess the effectiveness of different mesh materials in prophylactic mesh placement, and rank these materials according to the incidence of parastomal hernia (PSH) and other stoma complications.

METHOD

This network meta-analysis performed a systematic review and meta-analysis according to the Preferred Reporting Items for Systematic Review and Meta-Analysis statement. Four databases were searched for randomised controlled trials of prophylactic mesh placement. The aggregated results were performed in the STATA routine for Bayesian hierarchical random effects models.

RESULT

Thirteen randomised controlled trials from 1203 articles, met the inclusion criteria, including 681 cases without meshes, 65 cases with mesh material of xenogeneic acellular dermis (porcine/bovine), 27 cases with polypropylene/PG910, 114 cases with polypropylene/polyglecaprone (Monocryl), 117 cases with polypropylene/cellulose (ORC), 233 cases with polypropylene, and 35 cases with polypropylene/PVDF. In network A, compared with no mesh, only polypropylene (RR 0.24, 95% CI 0.04-0.80) were significantly associated with a reduction in the incidence of PSH. In network B, no statistical difference regarding stoma complications was found between mesh and no mesh.

CONCLUSION

Based on the network meta-analysis and ranking results, the polypropylene mesh material exhibited the best performance. However, this conclusion needs to be confirmed with larger sample sizes and high-quality randomised controlled trials.

In vivo soft tissue reinforcement with bacterial nanocellulose

The use of surgical meshes to reinforce damaged internal soft tissues has been instrumental for successful hernia surgery; a highly prevalent condition affecting yearly more than 20 million patients worldwide. Intraperitoneal adhesions between meshes and viscera are one of the most threatening complications, often implying reoperation or side effects such as chronic pain and bowel perforation. Despite recent advances in the optimization of mesh porous structure, incorporation of anti-adherent coatings or new approaches in the mesh fixation systems, clinicians and manufacturers are still pursuing an optimal material to improve the clinical outcomes at a cost-effective ratio. Here, bacterial nanocellulose (BNC), a bio-based polymer, is evaluated as a soft tissue reinforcement material regarding mechanical properties and in vivo anti-adhesive performance. A double-layer BNC laminate proved sufficient to meet the standards of mechanical resistance for abdominal hernia reinforcement meshes. BNC-polypropylene (BNC-PP) composites incorporating a commercial mesh have also been prepared. The in vivo study of implanted BNC patches in a rabbit model demonstrated excellent anti-adherent characteristics of this natural nanofibrous polymer 21-days after implantation and the animals were asymptomatic after the surgery. BNC emerges as a novel and versatile hernioplasty biomaterial with outstanding mechanical and anti-adherent characteristics.

Anti-inflammatory coating of hernia repair meshes: a 5-rabbit study

PURPOSE

Polymeric mesh implantation has become the golden standard in hernia repair, which nowadays is one of the most frequently performed surgeries in the world. However, many biocompatibility issues remain to be a concern for hernioplasty, with chronic pain being the most notable post-operative complication. Oxidative stress appears to be a major factor in the development of those complications. Lack of material inertness in vivo and oxidative environment formed by inflammatory cells result in both mesh deterioration and slowed healing process. In a pilot in vivo study, we prepared and characterized polypropylene hernia meshes with vitamin E (α-tocopherol)-a potent antioxidant. The results of that study supported the use of vitamin E as potential coating to alleviate post-surgical inflammation, but the pilot nature of the study yielded limited statistical data. The purpose of this study was to verify the observed trend of the pilot study statistically.

METHODS

In this work, we conducted a 5-animal experiment where we have implanted vitamin E-coated and uncoated control meshes into the abdominal walls of rabbits. Histology of the mesh-adjacent tissues and electron microscopy of the explanted mesh surface were conducted to characterize host tissue response to the implanted meshes.

RESULTS

As expected, modified meshes exhibited reduced foreign body reaction, as evidenced by histological scores for fatty infiltrates, macrophages, neovascularization, and collagen organization, as well as by the surface deterioration of the meshes.

CONCLUSION

In conclusion, results indicate that vitamin E coating reduces inflammatory response following hernioplasty and protects mesh material from oxidative deterioration.

Bioinspired Hydrogel Coating Based on Methacryloyl Gelatin Bioactivates Polypropylene Meshes for Abdominal Wall Repair

Considering the potential of hydrogels to mimic the cellular microenvironment, methacryloyl gelatin (GelMA) and methacryloyl mucin (MuMA) were selected and compared as bioinspired coatings for commercially available polypropylene (PP) meshes for ventral hernia repair. Thin, elastic hydrated hydrogel layers were obtained through network-forming photo-polymerization, after immobilization of derivatives on the surface of the PP fibers. Fourier transform infrared spectroscopy (FTIR) proved the successful coating while the surface morphology and homogeneity were investigated by scanning electron microscopy (SEM) and micro-computed tomography (micro-CT). The stability of the hydrogel layers was evaluated through biodynamic tests performed on the coated meshes for seven days, followed by inspection of surface morphology through SEM and micro-CT. Taking into account that platelet-rich plasma (PRP) may improve healing due to its high concentration of growth factors, this extract was used as pre-treatment for the hydrogel coating to additionally stimulate cell interactions. The performed advanced characterization proved that GelMA and MuMA coatings can modulate fibroblasts response on PP meshes, either as such or supplemented with PRP extract as a blood-derived bioactivator. GelMA supported the best cellular response. These findings may extend the applicative potential of functionalized gelatin opening a new path on the research and engineering of a new generation of bioactive meshes.

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.

Erratum: Addendum: Abdominal Wall Reconstruction: An Integrated Approach

[This corrects the article DOI: 10.1055/s-0038-1667062.].

Adhesions on polypropylene versus Sepramesh® meshes: an experimental study in rats

OBJECTIVE

to compare the formation of induced intraperitoneal adhesions in rats when using polypropylene and Sepramesh® meshes.

METHODS

we used 20 male Wistar rats, randomly grouped in two groups of ten animals each. We arranged two 10x20mm meshes intraperitoneally into each animal, one being the polypropylene (PP), and the other, Sepramesh®. In Group 1, the polypropylene mesh was positioned to the right, and the Sepramesh®, to the left. In Group 2, the meshes' layout was reversed. After 14 days of the procedure, we euthanized the animals and analyzed the incorporation and percentages of adhesions macroscopically in each mesh. We submitted the collected data to statistical analysis with a significance level of 5% (p<0.05).

RESULTS

all meshes showed adhesions. In the Sepramesh® ones, the percentage of surface covered by adhesions ranged from 2% to 86%, with a mean of 18.6±18.6%, while in the polypropylene meshes, it varied between 6% and 86%, with an average of 57.4%±34.9% (p<0.05). The preferred adhesion sites on both meshes were the edges.

CONCLUSION

although no mesh was able to completely inhibit the development of adhesions, the Sepramesh® mesh presented less adhesions to the polypropylene mesh. The most common sites of adhesion formation were the edges of the prosthesis, which evidences the importance of the adequate fixation of the meshes.

New advances in prophylactic mesh placement in end colostomy

Patients with end colostomy often undergo multiple operations because of high incidence and recurrence rates of parastoml hernia. Therefore, it is particularly important to prevent the occurrence of parastomal hernia when undergoing an end colostomy. Using a prophylactic mesh, which is developed and gradually recognized in recent years, is one of the methods to prevent parastomal hernia. Here, we review the application and new advances in prophylactic mesh placement in end colostomy.

Mesh materials and hernia repair

Hernia incidence has been observed since ancient time. Advancement in the medical textile industry came up with the variety of mesh materials to repair hernia, but none of them are without complications including recurrence of hernia. Therefore individuals once developed with the hernia could not lead a healthy and comfortable life. This drawn attention of surgeons, patients, researchers and industry to know the exact mechanism behind its development, complications and recurrence. Recent investigations highlighted the role of genetic factors and connective tissue disorders being the reason for the development of hernia apart from the abnormal pressure that is known to develop during other disease conditions. This review discusses different mesh materials, their advantages and disadvantages and their biological response after its implantation.

Past, Present and Future of Surgical Meshes: A Review

Surgical meshes, in particular those used to repair hernias, have been in use since 1891. Since then, research in the area has expanded, given the vast number of post-surgery complications such as infection, fibrosis, adhesions, mesh rejection, and hernia recurrence. Researchers have focused on the analysis and implementation of a wide range of materials: meshes with different fiber size and porosity, a variety of manufacturing methods, and certainly a variety of surgical and implantation procedures. Currently, surface modification methods and development of nanofiber based systems are actively being explored as areas of opportunity to retain material strength and increase biocompatibility of available meshes. This review summarizes the history of surgical meshes and presents an overview of commercial surgical meshes, their properties, manufacturing methods, and observed biological response, as well as the requirements for an ideal surgical mesh and potential manufacturing methods.

Two cases about mesh adhesion to intra-abdominal cavity tissue after using mesh to repair an incisional hernia

Abdominal incisional hernia is a common postoperative complication. With the development of a new type of surgical anti-adhesion mesh, mesh repair has become a widely-adopted procedure, particularly in the laparoscopic era. However, there were few reports about use of these new meshes to repair incisional hernia in the abdominal cavity. In this report, we present two cases: one a 72-year-old male and the other a 62-year-old female. Both of those patients suffered incisional hernias during abdominal operations, and therefore underwent open incisional hernia anti-adhesion mesh repair operations. Both of them had recurrent incisional hernias after the first repair operation. During the second hernia repair operation via laparoscopy, tissue from the intestine and omentum were found to have adhered seriously to the old meshes, which could cause many serious problems. We need to pay more attention to the issue of adhesion, try to determine possible reasons and improve in our future work.

Formation of adhesion after intraperitoneal application of TiMesh: experimental study on a rodent model

BACKGROUND

After laparoscopic repair of an incisive hernia, intraperitoneal prosthetic mesh, as a foreign material, is a strong stimulus for the development of adhesion, which may be the cause of serious complications. This experimental study compared three different meshes and their ability to prevent the formation of adhesion and shrinkage.

METHODS

Ninety rats were divided randomly into three groups: in Group 1 Proceed mesh was implanted, in Group 2 Ultrapro mesh was implanted, and in Group 3 TiMesh was implanted. Mesh samples were fixed as an intraabdominal mesh in the upper part of the abdomen. Ten animals from each group were sacrificed on days 7, 28 and 60 post-surgery. After opening the abdomen, the formation of adhesion was assessed according to the Surgical Membrane Study Group (SMSG) score, the percentage of shrinkage of the mesh was established and inflammatory reaction scored.

RESULTS

The SMSG score for adhesion was statistically significantly higher on all the postoperative days in the Proceed and Ultrapro mesh groups than in the TiMesh group which caused milder inflammatory reaction on 60th day than others meshes. The size of the mesh after 7 days was statistically significantly smaller in the Proceed and Ultrapro groups than in the TiMesh group, but after 60 days it was statistically significantly larger than in the TiMesh group.

CONCLUSION

The least formation of adhesion was noted in the TiMesh group, in which the highest level of shrinkage was noticed after 28 and 60 days. TiMesh has advantages over the other meshes studied, but a larger size mesh may be recommended for intraperitoneal application.

Surgical mesh for ventral incisional hernia repairs: Understanding mesh design

Surgical mesh has become an indispensable tool in hernia repair to improve outcomes and reduce costs; however, efforts are constantly being undertaken in mesh development to overcome postoperative complications. Common complications include infection, pain, adhesions, mesh extrusion and hernia recurrence. Reducing the complications of mesh implantation is of utmost importance given that hernias occur in hundreds of thousands of patients per year in the United States. In the present review, the authors present the different types of hernia meshes, discuss the key properties of mesh design, and demonstrate how each design element affects performance and complications. The present article will provide a basis for surgeons to understand which mesh to choose for patient care and why, and will explain the important technological aspects that will continue to evolve over the ensuing years.

The influence of mesh topology in the abdominal wall repair process

The tissue integration and the formation of adhesions in the repair of abdominal wall defects are principally led to the topology and the mechanical properties of implanted prosthesis. In this study we analyzed the influence of the topology of the meshes for abdominal wall repair, made of polypropylene (PP), evaluating its ability to prevent and to minimize the formation of adhesions, and to promote tissue ingrowth. Two series of in vivo studies were performed. In the first, two types of PP meshes, a lightweight macroporous mesh (LWM) and a heavyweight microporous mesh (HWM) were compared with determine the optimal porosity for tissue integration. In the second, a composite mesh, Clear Mesh Composite (CMC), made of a LWM sewn on a PP planar smooth film, was compared with a PP planar film, to demonstrate how two different topologies of same material are able to induce different tissue integration with the abdominal wall and different adhesion with internal organs. In both studies, the prostheses were implanted in Wistar rats and histological analysis and mechanical characterization of tissue coupled with the implants were performed. LWM showed better host tissue ingrowth in comparison to HWM. CMC prosthesis showed no adhesions to the viscera and no strong foreign body reaction, moreover its elasticity and anisotropy index were more similar to that of natural tissue. These results demonstrated that the surface morphology of PP surgical meshes allowed to modulate their repair ability. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1220-1228, 2016.

Berberine hydrochloride prevents postsurgery intestinal adhesion and inflammation in rats

Intestinal adhesion, characterized by connection of the loops of the intestine with other abdominal organs by fibrous tissue bands, remains an inevitable event of abdominal operations and can cause a number of complications. Berberine hydrochloride (berberine), a natural plant alkaloid derived from Chinese herbal medicine, is characterized by diverse pharmacological effects, such as anticancer and lower elevated blood glucose. This study is designed to investigate the effects of berberine on adhesion and inflammation after abdominal surgeries and the underlying molecular mechanisms. Adhesion severity grades and collagen deposition were assessed 14 days after surgery. We evaluated the levels of intercellular adhesion molecule-1 (ICAM-1) and inflammatory cytokines interleukin-1β (IL-1β), IL-6, transforming growth factor β (TGF-β), tumor necrosis factor-α (TNF-α), and examined transforming growth factor-activated kinase 1 (TAK1)/c-Jun N-terminal kinase (JNK) and TAK1/nuclear factor κB (NF-κB) signaling. The surgery group experienced the most severe adhesions, and berberine strikingly reduced the density and severity of adhesion. Results showed significant lower expression of IL-1β, IL-6, TGF-β, TNF-α, and ICAM-1, in berberine groups compared with the operation group. Activities of phosphorylated JNK and phosphorylated NF-κB were inhibited in the berberine groups compared with the surgery group. Our novel findings identified berberine hydrochloride as a promising strategy to prevent adhesion by downregulating ICAM-1 and reduce inflammation by inhibiting the TAK1/JNK and TAK1/NF-κB signaling after abdominal surgery, which brought out a good therapeutic approach for the development of clinical application for postoperative abdominal adhesion and inflammation.

Inflammatory reaction as determinant of foreign body reaction is an early and susceptible event after mesh implantation

PURPOSE

To investigate and relate the ultrashort-term and long-term courses of determinants for foreign body reaction as biocompatibility predictors for meshes in an animal model.

MATERIALS AND METHODS

Three different meshes (TVT, UltraPro, and PVDF) were implanted in sheep. Native and plasma coated meshes were placed bilaterally: (a) interaperitoneally, (b) as fascia onlay, and (c) as muscle onlay (fascia sublay). At 5 min, 20 min, 60 min, and 120 min meshes were explanted and histochemically investigated for inflammatory infiltrate, macrophage infiltration, vessel formation, myofibroblast invasion, and connective tissue accumulation. The results were related to long-term values over 24 months.

RESULTS

Macrophage invasion reached highest extents with up to 60% in short-term and decreased within 24 months to about 30%. Inflammatory infiltrate increased within the first 2 hours, the reached levels and the different extents and ranking among the investigated meshes remained stable during long-term follow up. For myofibroblasts, connective tissue, and CD31+ cells, no activity was detected during the first 120 min.

CONCLUSION

The local inflammatory reaction is an early and susceptible event after mesh implantation. It cannot be influenced by prior plasma coating and does not depend on the localisation of implantation.

Biocompatibility and adhesion formation of different endoloop ligatures in securing the base of the appendix

BACKGROUND AND OBJECTIVES

The common technique used in securing the base of the appendix is Endoloop ligature (Ethicon, Somerville, NJ, USA). Vicryl (polyglactin 910) (Ethicon) and polydioxanone (PDS) (Ethicon) Endoloop ligatures can be used. There are potential benefits of the use of PDS Plus (Ethicon) Endoloop ligature. However, the use of different materials may vary in terms of inflammation, foreign-body reaction, rate of infection in the surgical area, or rate of adhesion formation. An ideal suture would induce minimal inflammatory response and adhesion formation.

METHODS

Ninety rats were randomized into 3 groups: group I, in which appendectomy was performed with Vicryl ligature; group II, in which appendectomy was performed with PDS ligature; and group III, in which appendectomy was performed with PDS Plus ligature. The animals were killed on the seventh, 28th, and 60th days after surgery. The secured stump was used for histopathologic and immunohistochemistry analysis, as well as evaluation of the formation of adhesions.

RESULTS

Mild and moderate inflammation was more frequent in the PDS and PDS Plus groups than in the Vicryl group on the seventh postoperative day. There were no significant differences in the degree of inflammation on the 28th and 60th postoperative days. The lowest degree of postoperative adhesions was observed in the PDS group.

CONCLUSION

Milder postoperative inflammatory changes and a lower degree of postoperative adhesions were seen in the PDS ligature group, suggesting that this could be the standard Endoloop used to secure the base of the appendix.

Coating with autologous plasma improves biocompatibility of mesh grafts in vitro: development stage of a surgical innovation

Purpose. To investigate mesh coating modalities with autologous blood components in a recently developed in vitro test system for biocompatibility assessment of alloplastic materials. Materials and Methods. Seven different mesh types, currently used in various indications, were randomly investigated. Meshes were coated prior to cultivation with autologous peripheral blood mononuclear cells (PBMCs), platelets, and blood plasma. Pretreated meshes were incubated over 6 weeks in a minced tissue assay, representative for fibroblasts, muscle cells, and endothelial cells originating from 10 different patients. Adherence of those tissues on the meshes was microscopically investigated and semiquantitatively assessed using a previously described scoring system. Results. Coating with peripheral blood mononuclear cells did not affect the adherence score, whereas coating with platelets and blood plasma increased the score suggesting improved biocompatibility in vitro. The previous ranking of native meshes remained consistent after coating. Conclusion. Plasma coating of meshes improves their biocompatibility score in a novel in vitro test system.

Colonization by human fibroblasts of polypropylene prosthesis in a composite form for hernia repair

PURPOSE

Abdominal wall hernia is one of the commonest surgical disorders worldwide, and there is no single gold-standard operative technique to repair it. In an effort to improve techniques and technologies to reinforce hernia repair, synthetic meshes are employed. In this study, a new prosthesis (named composite) formed of two polypropylene layers, one macroporous (named mesh) and one transparent (named film), was examined to evaluate its capability to enable cell proliferation without inducing cell death. Inflammatory processes were also examined.

METHODS

Human fibroblasts BJ were seeded on multiwells, on which composite or film had been placed. After 7, 14, and 21 days, cell growth and viability, deposition of collagen, and release of IL-6, IL-1β, and TNF-α were evaluated.

RESULTS

The "in vitro" protocol showed the composite to be colonized by human fibroblasts on the polypropylene macroporous mesh side; no cell growth occurred on the film. The slowdown of cell growth observed between 14 and 21 days was accompanied by an increase in type I collagen deposition and marked fibroblast activity. Inflammatory cytokines initially increased, followed by their reduction beginning at 14 days.

CONCLUSIONS

The new prosthesis comprising two polypropylene layers of differing morphologies can be colonized by fibroblasts on the side facing the abdominal wall, whereas no cell growth occurs on the side facing the viscera. The transient inflammation, observed at early experimental times, is probably important for the healing process.

Ventral hernia repair with synthetic, composite, and biologic mesh: characteristics, indications, and infection profile

BACKGROUND

A variety of mesh materials are available for ventral hernia repair (VHR), each with a unique set of characteristics. Surgeons are offered an ever-expanding selection of products, making a review of the available materials timely.

METHODS

Current surgical literature is reviewed to describe the different types of synthetic mesh, the indications for the use of each type, their relative risks of infection, and other benefits and shortcomings. We also review clinical studies demonstrating outcomes, efficacy, and use of the meshes in different surgical settings, including laparoscopic hernia repair and special situations such as infection or large abdominal wall defects.

RESULTS

Three main types of prosthetic mesh are available. Synthetic mesh, such as polypropylene (PP) or polyester, is characterized by high tensile strength and vigorous tissue ingrowth, but is unsuitable for intra-abdominal placement because of its tendency to induce bowel adhesions. Composite, or barrier-coated, mesh is a dual-sided prosthetic having a synthetic parietal side to promote a strong repair and a visceral surface that repels tissue ingrowth and decreases adhesion formation. Biologic mesh is a collagen-based human, porcine, or bovine scaffold that may be implanted in the extra- or intra-peritoneal position. Biologic mesh is used frequently in the setting of infected or contaminated surgical incisions.

CONCLUSIONS

Synthetic PP mesh is an appropriate, durable material for extra-peritoneal placement in uncomplicated, clean VHR. Expanded polytetrafluoroethylene and composite meshes are suitable for intraperitoneal placement during laparoscopic VHR. Biologic meshes may be appropriate for contaminated fields or other special situations, but there is no consensus on when or how to use them.

Bioprosthetic mesh in abdominal wall reconstruction

Mesh materials have undergone a considerable evolution over the last several decades. There has been enhancement of biomechanical properties, improvement in manufacturing processes, and development of antiadhesive laminate synthetic meshes. The evolution of bioprosthetic mesh materials has markedly changed our indications and methods for complex abdominal wall reconstruction. The authors review the optimal properties of bioprosthetic mesh materials, their evolution over time, and their indications for use. The techniques to optimize outcomes are described using bioprosthetic mesh for complex abdominal wall reconstruction. Bioprosthetic mesh materials clearly have certain advantages over other implantable mesh materials in select indications. Appropriate patient selection and surgical technique are critical to the successful use of bioprosthetic materials for abdominal wall repair.

Conjugation of gold nanoparticles to polypropylene mesh for enhanced biocompatibility

Polypropylene mesh materials have been utilized in hernia surgery for over 40 years. However, they are prone to degradation due to the body's aggressive foreign body reaction, which may cause pain or complications, forcing mesh removal from the patient. To mitigate these complications, gold nanomaterials were attached to polypropylene mesh in order to improve cellular response. Pristine samples of polypropylene mesh were exposed to hydrogen peroxide/cobalt chloride solutions to induce formation of surface carboxyl functional groups. Gold nanoparticles were covalently linked to the mesh. Scanning electron microscopy confirmed the presence of gold nanoparticles. Differential scanning calorimetry and mechanical testing confirmed that the polypropylene did not undergo any significantly detrimental changes in physicochemical properties. A WST-1 cell culture study showed an increase in cellularity on the gold nanoparticle-polypropylene mesh as compared to pristine mesh. This study showed that biocompatibility of polypropylene mesh may be improved via the conjugation of gold nanoparticles.

Fabrication and characterization of porous EH scaffolds and EH-PEG bilayers

Biomaterials made from synthetic polymers are becoming more pervasive in the medical field. Synthetic polymers are particularly advantageous as their chemical and mechanical properties can be easily tailored to a specific application. This work characterizes polymer scaffolds derived from the cyclic acetal monomer 5-ethyl-5-(hydroxymethyl)-β,β-dimethyl-1,3-dioxane-2-ethanol diacrylate (EHD). Both porous scaffolds and bilayer scaffolds based upon the EHD monomer were fabricated, and the resulting scaffolds' degradation and mechanical properties were studied. The results showed that by modifying the architecture of an EH scaffold, either by adding a porous network or a poly(ethylene glycol) (PEG) coating, the degradation and Young's modulus of the biomaterial can be significant altered. However, results also indicated that these architectural modifications can be accomplished without a significant loss in the flexural strength of the scaffold. Therefore, we suggest that porous EH scaffolds, and particularly porous EH-PEG bilayers, may be especially useful in dynamic tissue environments due to their advantageous architectural and mechanical properties.

Adverse effects of polyvinylidene fluoride-coated polypropylene mesh used for laparoscopic intraperitoneal onlay repair of incisional hernia

BACKGROUND

Polyvinylidene fluoride-coated polypropylene meshes have been developed specifically for intraperitoneal onlay mesh repair. They combine a macroporous design with biomechanical characteristics compatible with the abdominal wall and are reported to have favourable antiadhesive properties. This retrospective study reports complications related to one of these materials, DynaMesh.

METHODS

Twenty-nine patients underwent intraperitoneal onlay mesh repair with DynaMesh at one of two hospitals. Patients characteristics, surgical procedures and postoperative analgesia were comparable at both sites.

RESULTS

Six patients developed DynaMesh-related complications that required surgical reintervention by laparotomy within 1 year of operation. Surgical reintervention was for adhesions in five patients and the mesh had to be explanted in three. One mesh was explanted because of early infection. Adhesions to DynaMesh were found in two patients who had surgery for unrelated reasons.

CONCLUSION

Laparoscopic intraperitoneal onlay DynaMesh repair was associated with a high rate of complications.

Subsequent abdominal surgery after laparoscopic ventral and incisional hernia repair with an expanded polytetrafluoroethylene mesh: a single institution experience with 72 reoperations

PURPOSE

Laparoscopic ventral and incisional hernia repair (LVIHR) carries a risk of adhesion formation and can influence subsequent abdominal operations (SAOs). We performed a retrospective study of findings during reoperations of patients who had previously had an LVIHR by using an expanded polytetrafluoroethylene mesh (DualMesh; WL Gore, Flagstaff, AZ, USA).

METHODS

The medical records of all 695 patients who had LVIHR at our hospital were reviewed. Patients who underwent SAO for various indications were identified (n = 72) and analyzed.

RESULTS

Seven LVIHR patients (1%) had early SAO (within a few days). In six patients (86%), removal of the mesh was required. Intra-operatively, in all six of these patients with peritonitis, there were no adhesions against the implant identified. Late SAOs (after more than 1 month) were performed in 65 patients (9.4%). Only one patient required acute surgical intervention due to an LVIHR-related adhesion (0.15%). Laparoscopy was performed in 83% and laparotomy in 17% of patients. Adhesions against the implant were present in 83% of patients; in 65%, the adhesions involved omentum only, and in 18%, they involved the bowel. Adhesiolysis was always easy and caused no inadvertent enterotomies. SAOs were devoid of postoperative complications.

CONCLUSIONS

In this largest series of reoperations after LVIHR, the majority of patients had mild or moderate adhesions against the implant. The specific observations that: (1) no relaparoscopies had to be converted, (2) no inadvertent enterotomies were made during adhesiolysis, and (3) SAOs have practically been devoid of peri- and postoperative complications indicate that SAOs can be safely performed after previous LVIHR with DualMesh.

Incisional ventral hernias: review of the literature and recommendations regarding the grading and technique of repair

Despite advances in surgical technique and prosthetic technologies, the risks for recurrence and infection are high following the repair of incisional ventral hernias. High-quality data suggest that all ventral hernia repairs should be reinforced with prosthetic repair materials. The current standard for reinforced hernia repair is synthetic mesh, which can reduce the risk for recurrence in many patients. However, permanent synthetic mesh can pose a serious clinical problem in the setting of infection. Assessing patients' risk for wound infection and other surgical-site occurrences, therefore, is an outstanding need. To our knowledge, there currently exists no consensus in the literature regarding the accurate assessment of risk of surgical-site occurrences in association with or the appropriate techniques for the repair of incisional ventral hernias. This article proposes a novel hernia grading system based on risk factor characteristics of the patient and the wound. Using this system, surgeons may better assess each patient's risk for surgical-site occurrences and thereby select the appropriate surgical technique, repair material, and overall clinical approach for the patient. A generalized approach and technical considerations for the repair of incisional ventral hernias are outlined, including the appropriate use of component separation and the growing role of biologic repair materials.

Surgical treatment of primary tracheal dyskinesia in a 14-month-old child--case report

The primary form of tracheal dyskinesia in early childhood is a rare congenital malformation of unknown origin. The degree of the posterior membranous tracheal wall involvement determines the intensity of obstruction and the severity of the clinical picture. The aim of this paper is to present a case of a 14-month-old child with severe tracheal dyskinesia that required surgical treatment. Fascia lata graft fixated with fibrin glue was used in strengthening the posterior tracheal wall. Three years following the surgery, the child is without breathing difficulties. In severe cases of primary dyskinesia, surgical treatment using fascia lata graft, fixated with fibrin glue is recommended in strengthening the posterior tracheal wall.