Abdominal wall hernia repair: from prosthetic meshes to smart materials

3D printing/electrospinning of a bilayered composite patch with antibacterial and antiadhesive properties for repairing abdominal wall defects

The application of patch methods for repairing abdominal wall wounds presents a variety of challenges, such as adhesion and limited mobility due to inadequate mechanical strength and nonabsorbable materials. Among these complications, postoperative visceral adhesion and wound infection are particularly serious. In this study, a bilayered composite patch with a gelatin methacryloyl (GelMA)/sodium alginate (SA)-vancomycin (Van)@polycaprolactone (PCL) (GelMA/SA-Van@PCL) antibacterial layer was prepared via coaxial 3D printing and a polycaprolactone (PCL)-silicon dioxide (SiO2) antiadhesive layer (PCL-SiO2) was prepared via electrospinning and electrostatic spray for hernia repair. The evaluation of the physicochemical properties revealed that the composite patch had outstanding tensile properties (16 N cm-1), excellent swelling (swelling rate of 243.81 ± 12.52%) and degradation (degradation rate of 53.14 ± 3.02%) properties. Furthermore, the composite patch containing the antibiotic Van exhibited good antibacterial and long-term drug release properties. Both in vivo and in vitro experiments indicated that the composite patch displayed outstanding biocompatibility and antiadhesive properties and could prevent postoperative infections. In summary, the bilayered composite patch can effectively prevent postoperative complications while promoting tissue growth and repair and holds significant application potential in hernia repair.

Comparison of postoperative outcomes between tissue glue and suture for mesh fixation in open tension-free inguinal hernia repair: a prospective analytical study

Introduction

A hernia is an abnormal protrusion of the viscus through the normal or abnormal opening of its containing cavity. Lichtenstein tension-free mesh repair is a commonly performed surgery for hernia. Various studies have revealed atraumatic fixation of the mesh produces less pain without compromising the outcomes.

Methods

This is a prospective analytical study conducted in a tertiary hospital over a year. Eighty patients with primary inguinal hernia undergoing open mesh repair were enrolled and divided into two groups with 40 patients in each group. Mesh fixation was done with N-butyl 2 cyano-acrylate glue in one group, while polypropylene 2-0 suture in the other group. Postoperative pain, the number of dosages of analgesia required, the incidence of hematoma/seroma formation, surgical site infection, and length of hospital stay were compared between the two groups. Data were analyzed using SPSS 25.

Results

Visual analog scores were significantly reduced in the glue group at 12 h and 24 h (P<0.05) with a reduction of the mean number of analgesic doses from 6.42±0.984 in the suture group to 5.95±0.597 in the glue group (P<0.05). The operating time was significantly reduced from 70.03±4.376 minutes in the suture group to 58.43±4.540 min in the glue group (P<0.05), while there was no significant difference in the length of hospital stay. Five percent of cases in the suture group developed seroma while no SSI was reported in this study.

Conclusions

This study demonstrates mesh fixation with cyanoacrylate glue in open hernioplasty for primary groin hernias is associated with reduced immediate postoperative pain, dose of analgesia required, and operating time in comparison to fixation with suture.

Polyvinylidene fluoride prosthetic reinforcement in abdominal wall hernia surgery

INTRODUCTION

Surgical repair of the anterior abdominal wall hernia is the most common intervention in general surgery practice. The introduction of synthetic prostheses reduces the frequency of recurrences, but in many cases, they are associated with complications that could seriously impair the quality of life of patients. To reduce perioperative complications, we introduced in our practice innovative prostheses made of a highly inert polymer, polyvinylidene fluoride (PVDF), and conducted an observational study.

The utilization of chitosan/Bletilla striata hydrogels to elevate anti-adhesion, anti-inflammatory and pro-angiogenesis properties of polypropylene mesh in abdominal wall repair

Polypropylene (PP) mesh is commonly used in abdominal wall repair due to its ability to reduce the risk of organ damage, infections and other complications. However, the PP mesh often leads to adhesion formation and does not promote functional tissue repair. In this study, we synthesized one kind of aldehyde Bletilla striata polysaccharide (BSPA) modified chitosan (CS) hydrogel based on Schiff base reaction. The hydrogel exhibited a porous network structure, a highly hydrophilic surface and good biocompatibility. We wrapped the PP mesh inside the hydrogel and evaluated the performance of the resulting composites in a bilateral 1 × 1.5 cm abdominal wall defect model in rats. The results of gross observation, histological staining and immunohistochemical staining demonstrated the positive impact of the CS hydrogel on anti-adhesion and wound healing effects. Notably, the addition of BSPA to the CS hydrogel further improved the performance of the composites in vivo, promoting wound healing by enhancing collagen deposition and capillary rearrangement. This study suggested that the BSPA-modified CS hydrogel significantly promoted the anti-adhesion, anti-inflammatory and pro-angiogenesis properties of PP meshes during the healing process. Overall, this work offers a novel approach to the design of abdominal wall repair patches.

The Impact of Technical Innovations and Donor-Site Mesh Repair on Autologous Abdominal-Based Breast Reconstruction-A Retrospective Analysis

Background: The aim of this study was to examine the potential benefit that may be achieved through the introduction of technical innovations and the incorporation of mesh for fascial donor site closure in uni- and bilateral autologous breast reconstruction with abdominal tissue. Methods: A retrospective single-center review of all breast reconstructions with a DIEP or MS-TRAM flap between January 2004 and December 2019 was performed. Donor and recipient site complications and operation times were evaluated before and after the implementation of coupler anastomoses, preoperative computed tomography angiography (CTA), indocyanine green (ICG) angiography, and the inclusion of mesh in donor site repair. Results: A total of 396 patients were included, accounting for 447 flaps. Operation time was significantly shorter in unilateral reconstructions after the implementation of CTA (p < 0.0001). ICG angiography significantly reduced the rates of partial flap loss (p = 0.02) and wound healing disorders (p = 0.02). For unilateral reconstructions, abdominal bulging or hernia was observed more often in MS1-TRAM flaps without synthetic mesh repair (p = 0.001), whereas conservatively treated seroma developed more frequently after mesh implantation (p = 0.03). Conclusions: Recent technological advancements developed over the past few decades have made a substantial impact on decreasing surgical duration and enhancing procedure safety.

Zwitterion mediated anti-protein adsorption on polypropylene mesh to reduce inflammation for efficient hernia repair

The effectiveness of polypropylene (PP) mesh is often compromised by severe inflammation. Engineering anti-inflammatory coatings has significant implications for PP mesh to repair unwanted hernias. Here, we presented a facile strategy to develop an anti-fouling coating consisting of zwitterionic poly(carboxybetaine methacrylate) (PCBMA), which could prohibit protein adsorption to endow PP mesh with anti-inflammatory efficacy. The incorporation of PCBMA coating had little impact on the raw features of PP mesh. While the modified mesh PCBMA-PP possessed noticeable hydrophilicity increase and surface charge reduction. The excellent lubricity and surface stability enabled PCBMA-PP to exhibit superior anti-fouling capacity, thus efficiently inhibiting the adsorption of proteins. In vivo experiments showed that incorporating the PCBMA layer could provide PP meshes with outstanding anti-inflammatory effects and tissue compatibility for repairing hernias.

Effect of Functionalization of Texturized Polypropylene Surface by Silanization and HBII-RGD Attachment on Response of Primary Abdominal and Vaginal Fibroblasts

Soft tissue defects, such as incisional hernia or pelvic organ prolapse, are prevalent pathologies characterized by a tissue microenvironment rich in fragile and dysfunctional fibroblasts. Precision medicine could improve their surgical repair, currently based on polymeric materials. Nonetheless, biomaterial-triggered interventions need first a better understanding of the cell-material interfaces that truly consider the patients' biology. Few tools are available to study the interactions between polymers and dysfunctional soft tissue cells in vitro. Here, we propose polypropylene (PP) as a matrix to create microscale surfaces w/wo functionalization with an HBII-RGD molecule, a fibronectin fragment modified to include an RGD sequence for promoting cell attachment and differentiation. Metal mold surfaces were roughened by shot blasting with aluminum oxide, and polypropylene plates were obtained by injection molding. HBII-RGD was covalently attached by silanization. As a proof of concept, primary abdominal and vaginal wall fasciae fibroblasts from control patients were grown on the new surfaces. Tissue-specific significant differences in cell morphology, early adhesion and cytoskeletal structure were observed. Roughness and biofunctionalization parameters exerted unique and combinatorial effects that need further investigation. We conclude that the proposed model is effective and provides a new framework to inform the design of smart materials for the treatment of clinically compromised tissues.

Spider-Silk-like Fiber Mat-Covered Polypropylene Warp-Knitted Hernia Mesh for Inhibition of Fibrosis under Dynamic Environment

Hernia surgery is a widely performed procedure, and the use of a polypropylene mesh is considered the standard approach. However, the mesh often leads to complications, including the development of scar tissue that wraps around the mesh and causes it to shrink. Consequently, there is a need to investigate the relationship between the mesh and scar formation as well as to develop a hernia mesh that can prevent fibrosis. In this study, three different commercial polypropylene hernia meshes were examined to explore the connection between the fabric structure and mechanical properties. In vitro dynamic culture was used to investigate the mechanism by which the mechanical properties of the mesh in a dynamic environment affect cell differentiation. Additionally, electrospinning was employed to create polycaprolactone spider-silk-like fiber mats to achieve mechanical energy dissipation in dynamic conditions. These fiber mats were then combined with the preferred hernia mesh. The results demonstrated that the composite mesh could reduce the activation of fibroblast mechanical signaling pathways and inhibit its differentiation into myofibroblasts in dynamic environments.

Are Surgeons Going to Be Left Holding the Bag? Incisional Hernia Repair and Intra-Peritoneal Non-Absorbable Mesh Implant Complications

Ventral incisional hernias are common indications for elective repair and frequently complicated by recurrence. Surgical meshes, which may be synthetic, bio-synthetic, or biological, decrease recurrence and, resultingly, their use has become standard. While most patients are greatly benefited, mesh represents a permanently implanted foreign body. Mesh may be implanted within the intra-peritoneal, preperitoneal, retrorectus, inlay, or onlay anatomic positions. Meshes may be associated with complications that may be early or late and range from minor to severe. Long-term complications with intra-peritoneal synthetic mesh (IPSM) in apposition to the viscera are particularly at risk for adhesions and potential enteric fistula formation. The overall rate of such complications is difficult to appreciate due to poor long-term follow-up data, although it behooves surgeons to understand these risks as they are the ones who implant these devices. All surgeons need to be aware that meshes are commercial devices that are delivered into their operating room without scientific evidence of efficacy or even safety due to the unique regulatory practices that distinguish medical devices from medications. Thus, surgeons must continue to advocate for more stringent oversight and improved scientific evaluation to serve our patients properly and protect the patient-surgeon relationship as the only rationale long-term strategy to avoid ongoing complications.

Electrospun fiber-based immune engineering in regenerative medicine

Immune engineering, a burgeoning field within regenerative medicine, involves a spectrum of strategies to optimize the intricate interplay between tissue regenerative biomaterials and the host tissue. These strategies are applied across different types of biomaterials and various disease models, which encompasses finely modulating the immune response at the levels of immune cells and factors, aiming to mitigate adverse effects like fibrosis and persistent inflammation that may arise at the injury site and consequently promote tissue regeneration. With the continuous progress in electrospinning technology, the immunoregulatory capabilities of electrospun fibers have gained substantial attention over the years. Electrospun fibers, with their extracellular matrix-like characteristics, high surface-area-to-volume ratio, and reliable pharmaceutical compound capacity, have emerged as key players among tissue engineering materials. This review specifically focuses on the role of electrospun fiber-based immune engineering, emphasizing their unique design strategies. Notably, electrospinning actively engages in immune engineering by modulating immune responses through four essential strategies: (i) surface modification, (ii) drug loading, (iii) physicochemical parameters, and (iv) biological grafting. This review presents a comprehensive overview of the intricate mechanisms of the immune system in injured tissues while unveiling the key strategies adopted by electrospun fibers to orchestrate immune regulation. Furthermore, the review explores the current developmental trends and limitations concerning the immunoregulatory function of electrospun fibers, aiming to drive the advancements in electrospun fiber-based immune engineering to its full potential.

A Review of Abdominal Meshes for Hernia Repair-Current Status and Emerging Solutions

Abdominal hernias are common issues in the clinical setting, burdening millions of patients worldwide. Associated with pain, decreased quality of life, and severe potential complications, abdominal wall hernias should be treated as soon as possible. Whether an open repair or laparoscopic surgical approach is tackled, mesh reinforcement is generally required to ensure a durable hernia repair. Over the years, numerous mesh products have been made available on the market and in clinical settings, yet each of the currently used meshes presents certain limitations that reflect on treatment outcomes. Thus, mesh development is still ongoing, and emerging solutions have reached various testing stages. In this regard, this paper aims to establish an up-to-date framework on abdominal meshes, briefly overviewing currently available solutions for hernia repair and discussing in detail the most recent advances in the field. Particularly, there are presented the developments in lightweight materials, meshes with improved attachment, antimicrobial fabrics, composite and hybrid textiles, and performant mesh designs, followed by a systematic review of recently completed clinical trials.

Killing two birds with one stone: A therapeutic copper-loaded bio-patch promoted abdominal wall repair via VEGF pathway

Hernia and life-threatening intestinal obstruction often result from abdominal wall injuries, and the regeneration of abdominal wall defects is limited due to the lack of biocompatible, antibacterial and angiogenic scaffolding materials for treating injured tissues. Taking inspiration from the facile preparation of dopamine polymerization and its surface modification technology, in this study, multi-therapeutic copper element was introduced into porcine small intestinal submucosa (SIS) bio-patches through polydopamine (PDA) deposition, in order to regenerate abdominal wall injury. In both in vitro antibacterial assays, cytocompatibility assays and in vivo abdominal wall repair experiments, the SIS/PDA/Cu bio-patches exhibited robust antibacterial efficiency (＞99%), excellent biocompatibility to cells (＞90%), and enhanced neovascularization and improved collagen maturity compared to other commercially available patches (3.0-fold higher than the PP mesh), due to their activation of VEGF pathway. These findings indicated the bio-patch was a promising application for preventing visceral adhesion, bacterial infection, and promoting soft tissue regeneration.

Novel Material Optimization Strategies for Developing Upgraded Abdominal Meshes

Over 20 million hernias are operated on globally per year, with most interventions requiring mesh reinforcement. A wide range of such medical devices are currently available on the market, most fabricated from synthetic polymers. Yet, searching for an ideal mesh is an ongoing process, with continuous efforts directed toward developing upgraded implants by modifying existing products or creating innovative systems from scratch. In this regard, this review presents the most frequently employed polymers for mesh fabrication, outlining the market available products and their relevant characteristics, further focusing on the state-of-the-art mesh approaches. Specifically, we mainly discuss recent studies concerning coating application, nanomaterials addition, stem cell seeding, and 3D printing of custom mesh designs.