Open inguinal hernia repair with the use of polyglycolic acid/trimethylene carbonate absorbable mesh: a critical update of the long-term results

Ventral Hernia Reconstruction with GORE ENFORM Biomaterial

Introduction: Ventral hernia repair (VHR) is one of the most common surgeries performed in the United States. Degradable mesh is the recommended choice for patients presenting with high-risk co-morbidities or increased risk for infection. GORE® ENFORM BiomaterialTM is a biosynthetic degradable mesh that has recently been approved for use in ventral hernia reconstruction with no reports of its clinical outcomes. Methods: This study was a single surgeon case series. Patients were included in the study if they underwent VHR with GORE® ENFORM BiomaterialTM. The decision to use GORE® ENFORM BiomaterialTM was the senior surgeon's decision based on the patient's center for disease control classification. Patient comorbidities, hernia characteristics, postoperative hernia recurrence, and surgical site occurrences (SSOs) were collected at in-patient follow-up appointments and chart review. Patients were asked to complete preoperative and postoperative patient-reported outcomes (PROs) using the Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Intensity short form 3a and the hernia-specific quality of life (HerQLes) survey. Results: A total of 15 patients were included in this study. The average length of follow-up was 315 days. Postoperatively, 26.7% of patients had an SSO with 4 surgical site infections. Two patients required an operative washout with mesh removal. One patient experienced hernia recurrence. Eight of the 15 patients completed preoperative and postoperative PROs. Conclusion: This is the first clinical study to report the outcomes of ventral hernia repair using ENFORM mesh. These results show that Enform mesh is an option to consider in complex ventral hernia reconstruction.

Fibroblast matrix implants-a better alternative for incisional hernia repair?

The standard surgical procedure for abdominal hernia repair with conventional prosthetic mesh still results in a high recurrence rate. In the present study, we propose a fibroblast matrix implant (FMI), which is a three-dimensional (3D) poly-L-lactic acid scaffold coated with collagen (matrix) and seeded with fibroblasts, as an alternative mesh for hernia repair. The matrix was seeded with fibroblasts (cellularized) and treated with a conditioned medium (CM) of human Umbilical Cord Mesenchymal Stem Cells (hUC-MSC). Fibroblast proliferation and function were assessed and compared between treated with CM hUC-MSC and untreated group, 24 h after seeding onto the matrix (n= 3). To study the matricesin vivo,the hernia was surgically created on male Sprague Dawley rats and repaired with four different grafts (n= 3), including a commercial mesh (mesh group), a matrix without cells (cell-free group), a matrix seeded with fibroblasts (FMI group), and a matrix seeded with fibroblasts and cultured in medium treated with 1% CM hUC-MSC (FMI-CM group).In vitroexamination showed that the fibroblasts' proliferation on the matrices (treated group) did not differ significantly compared to the untreated group. CM hUC-MSC was able to promote the collagen synthesis of the fibroblasts, resulting in a higher collagen concentration compared to the untreated group. Furthermore, thein vivostudy showed that the matrices allowed fibroblast growth and supported cell functionality for at least 1 month after implantation. The highest number of fibroblasts was observed in the FMI group at the 14 d endpoint, but at the 28 d endpoint, the FMI-CM group had the highest. Collagen deposition area and neovascularization at the implantation site were observed in all groups without any significant difference between the groups. FMI combined with CM hUC-MSC may serve as a better option for hernia repair, providing additional reinforcement which in turn should reduce hernia recurrence.

Multifunctional Fluorinated Lubricant-Infused Poly(4-Hydroxybutyrate) (P4HB) Membranes for Full-Thickness Abdominal Wall Defect Repair

Abdominal wall defect caused by surgical trauma, congenital rupture, or tumor resection may result in hernia formation or even death. Tension-free abdominal wall defect repair by using patches is the gold standard to solve such problems. However, adhesions following patch implantation remain one of the most challenging issues in surgical practice. The development of new kinds of barriers is key to addressing peritoneal adhesions and repairing abdominal wall defects. It is already well recognized that ideal barrier materials need to have good resistance to nonspecific protein adsorption, cell adhesion, and bacterial colonization for preventing the initial development of adhesion. Herein, electrospun poly(4-hydroxybutyrate) (P4HB) membranes infused with perfluorocarbon oil are used as physical barriers. The oil-infused P4HB membranes can greatly prevent protein attachment and reduce blood cell adhesion in vitro. It is further shown that the perfluorocarbon oil-infused P4HB membranes can reduce bacterial colonization. The in vivo study reveals that perfluoro(decahydronaphthalene)-infused P4HB membranes can significantly prevent peritoneal adhesions in the classic abdominal wall defects' model and accelerate defect repair, as evidenced by gross examination and histological evaluation. This work provides a safe fluorinated lubricant-impregnated P4HB physical barrier to inhibit the formation of postoperative peritoneal adhesions and efficiently repair soft-tissue defects.

Biosynthetic meshes in contaminated fields: where are we now? A systematic review and meta-analysis in humans

PURPOSE

Selection of an appropriate mesh reinforcement for hernia repair in contaminated fields is a significant problem for surgeons. To date the proper mesh for contaminated fields has not been found. Biosynthetic meshes have emerged as new treatment option in contaminated fields. This study aims to evaluate the postoperative outcomes of biosynthetic meshes in contaminated fields.

METHODS

Systematic electronic search (PubMed, Medline, Embase, Scopus), according to PRISMA criteria, was performed. A literature search of scientific papers was performed by two reviewers until April 2021. Articles were chosen based on reference to biosynthetic meshes, their use in infected fields, and in human subjects. GRADE methodology and the modified Newcastle-Ottawa scale were used to assess the quality of studies. According to CDC-Centers for Disease Control classes patients were divided into two subgroups, group 1 (CDC class 2) and group 2 (CDC classes 3-4).

RESULTS

The research included 21 articles and 1619 patients were analyzed. Long-term follow-up showed a significant higher recurrence rate than short-term follow-up. P < 0.001. Meta-analysis of these studies showed that the SSI were significantly higher in CDC classes 3-4 than CDC class 2 (P < 0.01). No differences were found in SSO (P = 0.06) and recurrence (P = 0.37) rate among the two groups. Phasix™ was the most common mesh in 15 studies. The mean follow-up was 23.0 months. The surgical site infection (SSI) rate was 17.3%. The surgical site occurrence (SSO) rate was 32.4%. Recurrence rate was 11.5%.

CONCLUSION

This is the first systematic review and meta-analysis on the clinical outcomes of abdominal wall repair using biosynthetic mesh in contaminated-infected settings. The results show good results in patients at high risk of postoperative wound complications. The aim of this study is to add to the growing literature on biosynthetic mesh a picture of current literature evidence to help future researchers performing further studies on this topic.

Polymer Hernia Repair Materials: Adapting to Patient Needs and Surgical Techniques

Biomaterials and their applications are perhaps among the most dynamic areas of research within the field of biomedicine. Any advance in this topic translates to an improved quality of life for recipient patients. One application of a biomaterial is the repair of an abdominal wall defect whether congenital or acquired. In the great majority of cases requiring surgery, the defect takes the form of a hernia. Over the past few years, biomaterials designed with this purpose in mind have been gradually evolving in parallel with new developments in the different surgical techniques. In consequence, the classic polymer prosthetic materials have been the starting point for structural modifications or new prototypes that have always strived to accommodate patients’ needs. This evolving process has pursued both improvements in the wound repair process depending on the implant interface in the host and in the material’s mechanical properties at the repair site. This last factor is important considering that this site—the abdominal wall—is a dynamic structure subjected to considerable mechanical demands. This review aims to provide a narrative overview of the different biomaterials that have been gradually introduced over the years, along with their modifications as new surgical techniques have unfolded.

Long term comparative evaluation of two types of absorbable meshes in partial abdominal wall defects: an experimental study in rabbits

PURPOSE

Synthetic prosthetic materials that are fully absorbable seek to reduce the host foreign body reaction and promote host tissue regeneration. This preclinical trial was designed to analyse, in the long term, the behaviour of two prosthetic meshes, one synthetic and one composed of porcine collagen, in abdominal wall reconstruction.

METHODS

Partial defects were created in the abdominal walls of New Zealand rabbits and repaired using a synthetic absorbable mesh (Phasix™) or a non-crosslinked collagen bioprosthesis (Protexa™). After 3, 6, 12 and 18 months, specimens were recovered for light microscopy and collagen expression analysis to examine new host tissue incorporation, macrophage response and biomechanical strength.

RESULTS

Both materials showed good host tissue incorporation in line with their spatial structure. At 18 months postimplant, Protexa™ was highly reabsorbed while the biodegradation of Phasix™ was still incomplete. Collagenization of both materials was good. Macrophage counts steadily decreased over time in response to Phasix™, yet persisted in the collagen meshes. At 18 months, zones of loose tissue were observed at the implant site in the absence of herniation in both implant types. The stress-stretch behaviour of Phasix™ implants decreased over time, being more pronounced during the period of 12-18 months. Nevertheless, the abdominal wall repaired with Protexa™ became stiffer over time.

CONCLUSION

Eighteen months after the implant both materials showed good compatibility but the biodegradation of Phasix™ and Protexa™ was incomplete. No signs of hernia were observed at 18 months with the stress-stretch relations being similar for both implants, regardless of the more compliant abdominal wall repaired with Protexa™ at short term.

Results at 3-year follow-up of totally extraperitoneal (TEP) hernia surgery with long-term resorbable mesh

INTRODUCTION

Synthetic non-resorbable mesh is almost standard in hernia surgery. However, several studies have showed negative effects of permanent implants such as chronic inflammation and complications involving different organs bordering the mesh. Such complications can raise the risk of chronic post-operative pain (CPP). Recently promising results regarding CPP have been published in patients with Lateral Inguinal Hernia (LIH) using a slowly resorbable mesh in Lichtenstein technique. For this reason the aim of the present study was to find the effect of a slowly resorbable implant on the long-term rate of hernia recurrence and chronic post-operative pain in patients with LIH repaired with TEP procedure.

METHODS

Prospective pilot study of TEP repair using TIGR^® Matrix Surgical Mesh in 35 primary LIH. At 3-year follow-up the Visual Analogue Scale (VAS) and the Inguinal Pain Questionnaire were employed to assess pain. Recurrence was determined by ultrasound and clinical examination.

RESULTS

All patients completed the pain questionnaires but one patient did not attend the planned clinical examination for the 3-year follow-up. No patients had CPP, as defined in the World Guidelines for Groin Hernia Management. Almost all patients had lower VAS score in any activity 3 years following surgery in comparison to the preoperative period. Three patients (8.8%) suffered symptomatic recurrence during the 3-year follow-up.

CONCLUSION

TEP repair in patients with LIH using a synthetic long-term resorbable mesh was found to be encouraging respecting chronic post-operative pain at 3-year follow-up but at the cost of an increased risk of recurrence.

Absorbable Meshes in Inguinal Hernia Surgery: A Systematic Review and Meta-Analysis

PURPOSE

Absorbable meshes used in inguinal hernia repair are believed to result in less chronic pain than permanent meshes, but concerns remain whether absorbable meshes result in an increased risk of recurrence. The aim of this study was to present an overview of the advantages and limitations of fully absorbable meshes for the repair of inguinal hernias, focusing mainly on postoperative pain and recurrence.

METHODS

This systematic review with meta-analyses is based on searches in PubMed, Embase, Cochrane, and Psychinfo. Included study designs were case series, cohort studies, randomized controlled trials (RCTs), and non-RCTs. Studies had to include adult patients undergoing an inguinal hernia repair with a fully absorbable mesh.

RESULTS

The meta-analyses showed no difference in recurrence rates (median 18 months follow-up) and chronic pain rates (1 year follow-up) between absorbable- and permanent meshes. Crude chronic pain rates for the RCTs were 2.1% for the absorbable meshes and 7.6% for the permanent meshes. For the absorbable meshes, medial hernias were more susceptible for recurrence compared with lateral hernias ( P < .0005). None of the studies reported allergic reactions or other serious adverse events related to the absorbable mesh.

CONCLUSIONS

Patients with an absorbable mesh seem to have less chronic pain following inguinal hernia surgery compared with permanent meshes, without increased risk of recurrence.

Design Strategies and Applications of Biomaterials and Devices for Hernia Repair

Hernia repair is one of the most commonly performed surgical procedures worldwide, with a multi-billion dollar global market. Implant design remains a critical challenge for the successful repair and prevention of recurrent hernias, and despite significant progress, there is no ideal mesh for every surgery. This review summarizes the evolution of prostheses design toward successful hernia repair beginning with a description of the anatomy of the disease and the classifications of hernias. Next, the major milestones in implant design are discussed. Commonly encountered complications and strategies to minimize these adverse effects are described, followed by a thorough description of the implant characteristics necessary for successful repair. Finally, available implants are categorized and their advantages and limitations elucidated, including non-absorbable and absorbable (synthetic and biologically derived) prostheses, composite prostheses, and coated prostheses. This review not only summarizes the state of the art in hernia repair, but also suggests future research directions toward improved hernia repair utilizing novel materials and fabrication methods.

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.

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.

Mesh implants: An overview of crucial mesh parameters

Hernia repair is one of the most frequently performed surgical interventions that use mesh implants. This article evaluates crucial mesh parameters to facilitate selection of the most appropriate mesh implant, considering raw materials, mesh composition, structure parameters and mechanical parameters. A literature review was performed using the PubMed database. The most important mesh parameters in the selection of a mesh implant are the raw material, structural parameters and mechanical parameters, which should match the physiological conditions. The structural parameters, especially the porosity, are the most important predictors of the biocompatibility performance of synthetic meshes. Meshes with large pores exhibit less inflammatory infiltrate, connective tissue and scar bridging, which allows increased soft tissue ingrowth. The raw material and combination of raw materials of the used mesh, including potential coatings and textile design, strongly impact the inflammatory reaction to the mesh. Synthetic meshes made from innovative polymers combined with surface coating have been demonstrated to exhibit advantageous behavior in specialized fields. Monofilament, large-pore synthetic meshes exhibit advantages. The value of mesh classification based on mesh weight seems to be overestimated. Mechanical properties of meshes, such as anisotropy/isotropy, elasticity and tensile strength, are crucial parameters for predicting mesh performance after implantation.

Inguinal hernia repair using a synthetic long-term resorbable mesh: results from a 3-year prospective safety and performance study

PURPOSE

Conventional meshes for hernia repair and abdominal wall reinforcement are usually made from polypropylene, polyester or other synthetic plastic materials known to promote foreign body reactions and a state of chronic inflammation that may lead to long-term complications. A novel approach is to use long-term resorbable implants like TIGR(®) Matrix Surgical Mesh. Preclinical studies have shown that this mesh maintains mechanical integrity beyond the point in time where newly formed tissue is capable of carrying the abdominal loads.

METHODS

This was a first-in-man, prospective, pilot study performed during 2009, at two sites in Sweden. Forty patients with primary inguinal hernias were enrolled for Lichtenstein repair using TIGR(®) Matrix Surgical Mesh. The primary endpoint was safety as assessed by monitoring the incidence of adverse events and serious adverse events (SAEs) both related and unrelated to the mesh. The secondary endpoint was pain or discomfort. Visual Analogue Scale (VAS) 0-10 and Inguinal Pain Questionnaire were used for scoring pain and discomfort. Included patients have been followed for 36 months using ultrasound in combination with clinical examination.

RESULTS

All patients followed a normal early postoperative course. After 12 months no SAEs were reported. None of the patients with an isolated lateral inguinal hernia (LIH) had developed a recurrence but 4 (44 %) with medial and 4 (33 %) with combined hernias had recurred at 36-month follow-up. After 3-year follow-up none of the patients with LIH reported pain in the VAS-form and none of those patients could feel the sensation of a mesh in their groin. In the total study population 5 (16 %) patients experienced chronic pain in the form of mild sporadic pain and 3 (9.7 %) patients could feel the sensation of a mesh in their groin.

CONCLUSION

The use of a synthetic long-term resorbable mesh (TIGR(®) Matrix Surgical Mesh) in Lichtenstein repair was found to be safe, without recurrences, and promising regarding pain/discomfort at 3-year follow-up in patients with LIH. However, patients with medial and combined inguinal hernias had high recurrence rates.

In vitro and in vivo characterization of a fully resorbable and composite surgical mesh

Fully resorbable and composite synthetic meshes are intended to provide advantages over nonabsorbable synthetic meshes, such as minimization of visceral adhesions and improved biocompatibility, but the inflammatory response to these materials has not previously been fully characterized. We compared resorbable and composite synthetic meshes using in vitro characterization and evaluated the host response in a nonhuman primate acute abdominal wall defect. After a 2-week in vitro incubation, resorbable synthetic mesh mechanical strength decreased to 0.12 ± 0.09 N (0.25% of initial strength), which preceded acidification and a fractured morphology at 1 month. The composite synthetic mesh strength decreased to 10.0 ± 3.2 N (41.1% of initial strength), coincident with morphological changes. In vivo, resorbable synthetic mesh elicited an intense yet transient foreign-body response, with macrophages and myofibroblasts persisting through 3 months of implantation. At 6 months, resorbable synthetic mesh was undetectable and the mesh–host tissue interface strength (14.7 ± 7.9 N) was equivalent to that of primary repair (21.4 ± 4.9 N). The composite synthetic mesh elicited a significant foreign-body response following 1 month of implantation. By 3 months, the composite synthetic mesh resorbable films had fully degraded, with foreign-body reaction localized to polypropylene fibers. By 6 months, macrophages had surrounded these polypropylene fibers, with a myofibroblast-positive capsule encircling a macrophage-rich layer. Resorbable and composite synthetic meshes may ultimately not be the most ideal biomaterials in situations where the biological response is expected to lead to a regeneration of host soft tissues.

Open inguinal hernia repair with the use of polyglycolic acid/trimethylene carbonate mesh: gross and pathologic assessment of the inguinal area at reoperation for recurrence

PURPOSE

Our group tried to test the hypothesis of using a totally absorbable material for open inguinal hernia repair. However, the increased incidence of recurrences alleviated our initial enthusiasm regarding the technique. The purpose of the present study was to attain both gross and microscopic data that could at least in part justify the hernia repair failure from a patient included in our initial pilot study and was re-operated for recurrence.

METHODS

A 65-year-old male patient was diagnosed clinically with a recurrence 24 months after open inguinal hernia repair with the use of polyglycolic acid/trimethylene carbonate mesh. The patient was operated for the recurrence upon our group on July 2012. The gross appearance of the inguinal area as well as the degree of chronic inflammation provoked by the used mesh as depicted by the pathologic analysis of specimens obtained intraoperatively were assessed.

RESULTS

An open tension-free repair with the use of a non-absorbable mesh under spinal anesthetic was undertaken. Intraoperatively, after the division of the external oblique aponeurosis, only minor fibrotic reaction was observed a finding that was additionally confirmed pathologically.

CONCLUSION

Polyglycolic acid/trimethylene carbonate mesh used for inguinal hernia repair was associated with a minimal inflammatory host reaction in the inguinal area at 3 years verified both grossly and microscopically.