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

Emerging materials and technologies for advancing bioresorbable surgical meshes

Surgical meshes play a significant role in the treatment of various medical conditions, such as hernias, pelvic floor issues, guided bone regeneration, and wound healing. To date, commercial surgical meshes are typically made of non-absorbable synthetic polymers, notably polypropylene and polytetrafluoroethylene, which are associated with postoperative complications, such as infections. Biological meshes, based on native tissues, have been employed to overcome such complications, though mechanical strength has been a main disadvantage. The right balance in mechanical and biological performances has been achieved by the advent of bioresorbable meshes. Despite improvements, recurrence of clinical complications associated with surgical meshes raises significant concerns regarding the technical adequacy of current materials and designs, pointing to a crucial need for further development. To this end, current research focuses on the design of meshes capable of biomimicking native tissue and facilitating the healing process without post-operative complications. Researchers are actively investigating advanced bioresorbable materials, both synthetic polymers and natural biopolymers, while also exploring the performance of therapeutic agents, surface modification methods and advanced manufacturing technologies such as 4D printing. This review seeks to evaluate emerging biomaterials and technologies for enhancing the performance and clinical applicability of the next-generation surgical meshes. STATEMENT OF SIGNIFICANCE: In the ever-transforming landscape of regenerative medicine, the embracing of engineered bioabsorbable surgical meshes stands as a key milestone in addressing persistent challenges and complications associated with existing treatments. The urgency to move beyond conventional non-absorbable meshes, fraught with post-surgery complications, emphasises the necessity of using advanced biomaterials for engineered tissue regeneration. This review critically examines the growing field of absorbable surgical meshes, considering their potential to transform clinical practice. By strategically combining mechanical strength with bioresorbable characteristics, these innovative meshes hold the promise of mitigating complications and improving patient outcomes across diverse medical applications. As we navigate the complexities of modern medicine, this exploration of engineered absorbable meshes emerges as a promising approach, offering an overall perspective on biomaterials, technologies, and strategies adopted to redefine the future of surgical meshes.

From Meshes to Minimally Invasive Techniques: A Comprehensive Review of Modern Hernia Repair Approaches

Hernias are a common medical condition characterized by the protrusion of organs or tissues through weakened muscle walls, affecting millions worldwide annually. Historically, from being treated with open surgeries using tension-free mesh repairs, the landscape of hernia repair has evolved significantly. This evolution has been marked by the advent and refinement of minimally invasive techniques, including laparoscopic and robotic-assisted approaches, which offer reduced postoperative pain, shorter recovery times, and improved patient outcomes compared to traditional methods. This comprehensive review aims to elucidate the evolution of hernia repair techniques, emphasizing the transition from conventional mesh repairs to advanced minimally invasive methodologies. By examining the historical progression and current state of hernia surgery, this review thoroughly analyzes the advancements in surgical techniques, materials, and technologies. Furthermore, it explores emerging trends such as biological meshes, ultrasound-guided procedures, and 3D printing applications in hernia repair. The clinical significance of these advancements lies in their potential to enhance the patient's quality of life, minimize complications, and optimize healthcare resource utilization. Insights gained from this review will inform clinicians and researchers about the efficacy, safety, and comparative effectiveness of various hernia repair approaches, guiding future directions in hernia management and fostering innovation in surgical practice.

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.

Development and Implantation of 3D Anatomically Tailored Polypropylene Mesh for Laparoscopic Inguinal Hernia Repair Designed on the Basis of CT Images (the ILAM Study)

OBJECTIVE

The aim of the ILAM (Individualized Laparoscopic Anatomical Mesh) study was to create and implant a fully individualized mesh based on CT scans, taking into account the published body of knowledge about the material and mechanical behavior of the implant for laparoscopic inguinal hernia repair.

SUMMARY BACKGROUND DATA

The team creating and conducting this study consisted of surgeons and engineers. A specific project was made and divided into 4 phases.

METHODS

The process of development and implantation was divided into 4 milestones: CT scans and modeling based on predefined subgroups, mesh manufacture, certification and clinical evaluation.

RESULTS

The result of the study was the first individually designed hernia mesh to have been implanted in a human subject. After 12 months of follow-up, no recurrences or other complications were reported.

CONCLUSIONS

The new mesh provides a better anatomic fit to the patients' inguinal region geometry. Mechanical stability is ensured by the multiple contact points between the implant and the tissues, which generate friction forces. Together with the possibility of shape design (proper overlap), the authors believe that there is no need for mesh fixation. If so, the use of such design meshes can change the guidelines in laparoendoscopic hernia repair in the future.

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.

Shape-Configurable Mesh for Hernia Repair by Synchronizing Anisotropic Body Motion

Continuous progress has been made in elucidating the relationship between material property, device design, and body function to develop surgical meshes. However, an unmet need still exists wherein the surgical mesh can handle the body motion and thereby promote the repair process. Here, the hernia mesh design and the advanced polymer properties are tailored to synchronize with the anisotropic abdominal motion through shape configuration. The thermomechanical property of shape configurable polymer enables molding of mesh shape to fit onto the abdominal structure upon temperature shift, followed by shape fixing with the release of the heat energy. The microstructural design of mesh is produced through finite element modeling to handle the abdominal motion efficiently through the anisotropic longitudinal and transverse directions. The design effects are validated through in vitro, ex vivo, and in vivo mechanical analyses using a self-configurable, body motion responsive (BMR) mesh. The regenerative function of BMR mesh leads to effective repair in a rat hernioplasty model by effectively handling the anisotropic abdomen motion. Subsequently, the device-tissue integration is promoted by promoting healthy collagen synthesis with fibroblast-to-myofibroblast differentiation. This study suggests a potential solution to promote hernia repair by fine-tuning the relationship between material property and mesh design.

Characterization and in vivo evaluation of a fabricated absorbable poly(vinyl alcohol)-based hernia mesh

The most widely taken medical approach toward hernia repair involves the implementation of a prosthetic mesh to cover the herniated site and reinforce the weakened area of the abdominal wall. Biodegradable meshes can serve as biocompatible grafts with a low risk of infection. However, their major complication is associated with a high rate of degradation and hernia recurrence. We proposed a facile and cost-effective method to fabricate a poly(vinyl alcohol)-based mesh, using the solution casting technique. The inclusion of zinc oxide nanoparticles, citric acid, and three cycles of freeze-thaw were intended to ameliorate the mechanical properties of poly(vinyl alcohol). Several characterization, cell culture, and animal studies were conducted. Swelling and water contact angle measurements confirmed good water uptake capacity and wetting behavior of the final mesh sample. The synthesized mesh acquired a high mechanical strength of 52.8 MPa, and its weight loss was decreased to 39 %. No cytotoxicity was found in all samples. In vivo experiments revealed that less adhesion and granuloma formation, greater tissue integration, and notably higher neovascularization rate were resulted from implanting this fabricated hernia mesh, compared to commercial Prolene® mesh. Furthermore, the amount of collagen deposition and influential growth factors were enhanced when rats were treated with the proposed mesh instead of Prolene®.

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.

Natural polymer-based scaffolds for soft tissue repair

Soft tissues such as skin, muscle, and tendon are easily damaged due to injury from physical activity and pathological lesions. For soft tissue repair and regeneration, biomaterials are often used to build scaffolds with appropriate structures and tailored functionalities that can support cell growth and new tissue formation. Among all types of scaffolds, natural polymer-based scaffolds attract much attention due to their excellent biocompatibility and tunable mechanical properties. In this comprehensive mini-review, we summarize recent progress on natural polymer-based scaffolds for soft tissue repair, focusing on clinical translations and materials design. Furthermore, the limitations and challenges, such as unsatisfied mechanical properties and unfavorable biological responses, are discussed to advance the development of novel scaffolds for soft tissue repair and regeneration toward clinical translation.

Antimicrobial Meshes for Hernia Repair: Current Progress and Perspectives

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