Inguinal hernia repair using a synthetic long-term resorbable mesh: results from a 3-year prospective safety and performance study. Hernia. 2014;18:723-730. [PMID: 24770701 PMCID: PMC4177566 DOI: 10.1007/s10029-014-1249-1]

Application of bridging mesh repair in giant ventral incisional hernia

Achieving ideal abdominal wall reconstruction in giant ventral incisional hernia has been a challenging for surgeons. This study aimed to verify the safety and efficacy of bridging repair by comparing it with primary fascial closure (PFC) repair in the treatment of giant ventral incisional hernia. We retrospectively analyzed the clinical data of 92 patients with giant ventral incisional hernia who underwent mesh repair at our medical institution from January 1, 2014 to December 31, 2020. Patients were divided into 2 groups: the bridging repair group with 40 patients in whom repair was completed using the bridging technique and the PFC group with 52 patients in whom primary fascial closure was achieved and all patients underwent mesh reinforcement during the operation. The main outcome measures were recurrence rate and morbidity, especially intra-abdominal hypertension (IAH). Follow-up time of both groups lasted at least 24 months after surgery. After a median of 46 months and 65 months of follow-up, respectively, in the two groups, bridging repair did not increase the long-term recurrence rate (2.56%) in the larger defect area group compared to the PFC group (1.96%). There were no significant differences in perioperative morbidity, IAH, incidence of postoperative chronic pain, and sensory impairment of the abdominal wall between both groups. The application of bridging surgery in the treatment of complex giant ventral incisional hernias is safe and effective and does not significantly increase the postoperative recurrence rate.

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.

Nerve identification during open inguinal hernia repair: a systematic review and meta-analyses

PURPOSE

Inguinal hernia repair is one of the most common operations worldwide and despite this, the incidence of chronic pain remains high after inguinal hernia repair. The optimal nerve handling strategy is controversial and the rate at which nerves are identified remains uncertain. This study aimed to determine the identification rates of the ilioinguinal, iliohypogastric, and genitofemoral nerves as well as nerve handling strategies.

METHODS

This review was registered on PROSPERO (CRD 42023416576). PubMed, Embase, and Cochrane Central were systematically searched. Studies with more than 10 patients were included if they reported an identification rate for at least one of the nerves during elective open inguinal hernia repair in adults. Studies requiring nerve identification in their study design were excluded. Bias was assessed with the JBI critical appraisal tool and Cochrane's RoB-2 tool. The overall estimate of the prevalence was analysed with prevalence meta-analyses.

RESULTS

A total of 23 studies were included. The meta-analyses included 18 studies, which resulted in an identification rate of 82% (95% CI: 76-87%) for the ilioinguinal nerve, 62% (95% CI: 54-71%) for the iliohypogastric nerve, and 41% (95% CI: 27-55%) for the genitofemoral nerve. Nerves were spared in 82% of all repairs.

CONCLUSION

The ilioinguinal, iliohypogastric, and genitofemoral nerves were identified in 82%, 62%, and 41% of surgeries, respectively. Most studies used a nerve-preserving strategy. The role of nerve identification in the development of chronic pain remains uncertain, as well as the optimal nerve handling strategy.

The Effects of Tissue Healing Factors in Wound Repair Involving Absorbable Meshes: A Narrative Review

Wound healing is a complex and meticulously orchestrated process involving multiple phases and cellular interactions. This narrative review explores the intricate mechanisms behind wound healing, emphasizing the significance of cellular processes and molecular factors. The phases of wound healing are discussed, focusing on the roles of immune cells, growth factors, and extracellular matrix components. Cellular shape alterations driven by cytoskeletal modulation and the influence of the 'Formin' protein family are highlighted for their impact on wound healing processes. This review delves into the use of absorbable meshes in wound repair, discussing their categories and applications in different surgical scenarios. Interleukins (IL-2 and IL-6), CD31, CD34, platelet rich plasma (PRP), and adipose tissue-derived mesenchymal stem cells (ADSCs) are discussed in their respective roles in wound healing. The interactions between these factors and their potential synergies with absorbable meshes are explored, shedding light on how these combinations might enhance the healing process. Recent advances and challenges in the field are also presented, including insights into mesh integration, biocompatibility, infection prevention, and postoperative complications. This review underscores the importance of patient-specific factors and surgical techniques in optimizing mesh placement and healing outcomes. As wound healing remains a dynamic field, this narrative review provides a comprehensive overview of the current understanding and potential avenues for future research and clinical applications.

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.

Transversalis fascia suture reinforcement may facilitate the performance of electrospun P(LLA-CL) nanoscale fibrinogen mesh in inguinal hernia repair: a prospective single-center cohort study

The aim of this study was to evaluate a new electrospun P(LLA-CL) nanoscale fibrinogen mesh performance in real-world clinical practice. A prospective, single-center evaluation of Lichtenstein inguinal hernia repair using electrospun P(LLA-CL) nanoscale fibrinogen mesh in elderly patients with comorbid diseases was conducted between 2020 and 2022. A suture reinforcement of transversalis fascia was applied before mesh implantation. Hernia recurrence, pain score and overall complication rate were measured. A total of 52 inguinal hernias in 48 patients were included. The age of patients ranged from 33 to 95 years, with a median of 78 years. Comorbid conditions included cardiopulmonary disease, organ dysfunction, anticoagulant use, diabetes and smoking. By optimizing the physical condition perioperatively, all patients finished treatment successfully. Four cases recurred secondary to direct hernias or combined hernias and were diagnosed in the first 24 case cohort during follow-up. With surgical procedural modification involving strengthening the posterior inguinal floor by reef-up suturing of the transversalis fascia and the inferior edge of mesh slit to accommodate the spermatic cord, no further recurrence was diagnosed. Postoperative pain was mild and the pain score decreased three months after surgery compared to 1 week after surgery (p = 0.0099). No severe complications occurred, while seroma occurred in six cases. Electrospun P(LLA-CL) nanoscale fibrinogen mesh is safe and effective in repairing inguinal hernias in elderly patients with comorbid disease. A strengthening of the transversalis fascia by suturing may enhance the performance of this mesh.

Characterisation of Selected Materials in Medical Applications

Tissue engineering is an interdisciplinary field of science that has developed very intensively in recent years. The first part of this review describes materials with medical and dental applications from the following groups: metals, polymers, ceramics, and composites. Both positive and negative sides of their application are presented from the point of view of medical application and mechanical properties. A variety of techniques for the manufacture of biomedical components are presented in this review. The main focus of this work is on additive manufacturing and 3D printing, as these modern techniques have been evaluated to be the best methods for the manufacture of medical and dental devices. The second part presents devices for skull bone reconstruction. The materials from which they are made and the possibilities offered by 3D printing in this field are also described. The last part concerns dental transitional implants (scaffolds) for guided bone regeneration, focusing on polylactide-hydroxyapatite nanocomposite due to its unique properties. This section summarises the current knowledge of scaffolds, focusing on the material, mechanical and biological requirements, the effects of these devices on the human body, and their great potential for applications.

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.

A Prospective, Single Arm, Multi-Center Study Evaluating the Clinical Outcomes of Ventral Hernias Treated with OviTex® 1S Permanent Reinforced Tissue Matrix: The BRAVO Study 12-Month Analysis

BACKGROUND

Conflicting results from previous studies have led to dissent over whether surgical mesh is safe and effective in ventral hernia repair. A newer class of mesh known as a reinforced tissue matrix, combining a biologic scaffold and minimal polymer reinforcement, offers promise in reducing inflammatory response and increasing abdominal wall support. This study sought to assess the clinical utility of a reinforced tissue matrix (OviTex) in ventral hernia repair 12 months after implantation.

METHODS

This is a prospective, single-arm, multi-center study to evaluate the clinical performance of OviTex^® 1S Permanent (OviTex) in the repair of primary or recurrent ventral hernias (VH) in consecutive patients (ClinicalTrials.gov/NCT03074474). The rate of surgical site occurrences (SSOs) was evaluated 90 days post-surgery as the primary endpoint. Hernia recurrence and the incidence of postoperative events were evaluated between three and 12 months as secondary endpoints. The incidence of other complications and patient-reported outcomes were also recorded.

RESULTS

Ninety-two (92) patients were enrolled in the study, of whom seventy-six (76) reached the 12-month follow-up. All patients were at least 18 years of age with a BMI of <40 kg/m². Hernia defects were <20 × 20 cm, classified as class I-III according to the CDC wound classification system. Of the 76 patients who reached 12-month follow-up, twenty-six (34%) had previous VH repairs and thirteen (17%) had previous surgical infection. Sixty (79%) had factors known to increase the risk of recurrence. Twenty patients (26%) experienced SSOs, with ten (13%) requiring procedural intervention. Two of the 75 patients (2.7%) experienced a recurrence.

CONCLUSIONS

The low rate of hernia recurrence and SSOs requiring intervention illustrates the potential that reinforced tissue matrices, and OviTex 1S, in particular, have to improve outcomes in VH repairs. Follow-up to 24 months is ongoing.

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.

Observational Cohort Study on the Use of a Slowly Fully Resorbable Synthetic Mesh (Phasix™) in the Treatment of Complex Abdominal Wall Pathology with Different Grades of Contamination

PURPOSE

Abdominal wall hernia repair in contaminated cases remains a therapeutic challenge due to the high risk of post-operative surgical site occurrences (SSO). Slowly resorbable synthetic (biosynthetic) meshes have recently been introduced and may offer unique advantages when challenged with bacterial colonization during abdominal wall reconstruction.

METHODS

A multicenter single-arm retrospective observational cohort study examined all consecutive patients in whom a poly-4-hydroxybutyrate mesh (Phasix™ or Phasix™ ST; Becton Dickinson, Franklin Lakes, NJ, USA) was used for the repair of an inguinal or ventral/incisional hernia, or to replace an infected synthetic mesh. Patient records were analyzed according to the level of contamination, using the classification score of the Centers for Disease Control and Prevention (CDC). The primary objective was to evaluate short-term postoperative morbidity by assessing SSOs and the need for reoperation or even mesh excision.

RESULTS

A total of 47 patients were included. The median age was 68 years (30-87), the male/female ratio was 26/21, and the median BMI was 26.5 kg/m2 (16.4-46.8). There were 17 clean cases, 17 clean-contaminated, 6 contaminated and 7 dirty. Median follow-up time was 48 days. An SSO was seen in 4 clean (23.5%), 7 clean-contaminated (41.2%), 2 contaminated (33.3%) and 5 dirty cases (71.4%). A surgical site occurrence requiring procedural intervention (SSOPI) was seen in 2 clean (11.8%), 3 clean-contaminated (17.6%), 1 contaminated (16.7%) and 2 dirty cases (28.6%). Hernia recurrence was seen in 1 clean (5.9%), 2 clean-contaminated (11.8%) and 3 dirty cases (42.9%). Mesh excision had to be performed in only one case in the contaminated group.

CONCLUSION

The Phasix™ mesh shows promising short-term results when used in contaminated hernia-related surgery. Even in contaminated or dirty conditions, with or without infection of the mesh, resection of the mesh only had to be performed once and patients could be managed either conservatively or by relatively minor reoperations. However, further research is needed to fully evaluate the safety and efficacy of these meshes.

Evaluation of a Novel Absorbable Mesh in a Porcine Model of Abdominal Wall Repair

Bioabsorbable meshes have seen increasing clinical use to reinforce soft tissue, and exist on a spectrum of strength loss versus absorption: several retain their strength for months, but remain in situ for years. Others lose strength fully by 6 weeks. An intermediate profile, with some strength for 3 -4 months, but consistent absorption in less than a year, may be an optimal balance of near-term support and long-term safety. In this large animal study, we evaluate such a mesh (DuraSorb, SIA), assessing its utility in a porcine model of abdominal wall repair.

METHODS

Two full-thickness defects were created in the abdominal walls of nine Yucatan swine via midline approach and repaired preperitoneally with either DuraSorb or long-lasting control mesh (TIGR, Novus Scientific). At 30 days, 3 months, and 1 year, the implantations were assessed by clinical pathology, post-necropsy histopathology, and burst strength testing.

RESULTS

No device-associated complications were found in vivo, at necropsy, or histologically. DuraSorb was well-integrated and vascularized by 30 days. DuraSorb demonstrated minimal/mild inflammation and fibroplasia, and lower inflammatory scores when compared with TIGR at all time points (P < 0.05). Burst strength of the repair sites was higher than adjacent abdominal wall at all time points (P < 0.05).

CONCLUSIONS

DuraSorb provided durable long-term support, minimal inflammation, and consistent absorption in this porcine model of abdominal wall repair, as compared to a long-term control. Clinical data is needed, but these results suggest that this mesh provides adequate structural support while potentially reducing long-term device reactions.

Regulatory science for hernia mesh: Current status and future perspectives

Regulatory science for medical devices aims to develop new tools, standards and approaches to assess the safety, effectiveness, quality and performance of medical devices. In the field of biomaterials, hernia mesh is a class of implants that have been successfully translated to clinical applications. With a focus on hernia mesh and its regulatory science system, this paper collected and reviewed information on hernia mesh products and biomaterials in both Chinese and American markets. The current development of regulatory science for hernia mesh, including its regulations, standards, guidance documents and classification, and the scientific evaluation of its safety and effectiveness was first reported. Then the research prospect of regulatory science for hernia mesh was discussed. New methods for the preclinical animal study and new tools for the evaluation of the safety and effectiveness of hernia mesh, such as computational modeling, big data platform and evidence-based research, were assessed. By taking the regulatory science of hernia mesh as a case study, this review provided a research basis for developing a regulatory science system of implantable medical devices, furthering the systematic evaluation of the safety and effectiveness of medical devices for better regulatory decision-making. This was the first article reviewing the regulatory science of hernia mesh and biomaterial-based implants. It also proposed and explained the concepts of evidence-based regulatory science and technical review for the first time.

A Novel Use of Fully Absorbable PhasixTM Mesh for Laparoscopic Inguinal Hernia Repair

Background and Objectives

An inguinal hernia is usually repaired with synthetic nonabsorbable mesh, resulting in collagen formation, chronic inflammation, and fibrosis, with significantly reduced hernia recurrence. However, chronic pain may affect the quality of life. Poly-4-hydroxybutyrate (P4HB) mesh was introduced to minimize complications, and starts to degrade in 12-18 months. This study assesses the consequences and results of patients undergoing transabdominal preperitoneal (TAPP) inguinal hernia repair using P4HB mesh (Phasix^TM, C.R. Bard Inc., Murray Hill, NJ, USA).

Methods

We performed a pilot study of laparoscopic TAPP repair for inguinal hernias using P4HB mesh in 15 patients (14 male and one female) with an average age of 55.8 y, and an average body mass index of 27.4 kg/m². We assessed the recurrence rate and patients' chronic pain for 30 months, with institutional review board approval (E-19-3735). The study was conducted from January 2016 to July 2017 in Medical City, King Saud University. We measured postoperative pain, reactions, mesh sensation, discomfort, and recurrence.

Results

In 15 patients, we encountered no recurrence or mesh sensation, except in one patient, who experienced mild chronic inguinal pain for one year, without activity restrictions.

Conclusion

Laparoscopic TAPP inguinal hernia repair using P4HB mesh is safe for combined, direct (medial), and indirect (lateral) inguinal hernia, with no recurrence. P4HB absorbable mesh caused less chronic pain and discomfort. Longer follow-up, more patients and 15 patients repaired using synthetic mesh are necessary to assess the utility of P4HB for inguinal hernia repair globally.

Prospective, multicenter study of P4HB (Phasix™) mesh for hernia repair in cohort at risk for complications: 3-Year follow-up

BACKGROUND

This study represents a prospective, multicenter, open-label study to assess the safety, performance, and outcomes of poly-4-hydroxybutyrate (P4HB, Phasix™) mesh for primary ventral, primary incisional, or multiply-recurrent hernia in subjects at risk for complications. This study reports 3-year clinical outcomes.

MATERIALS AND METHODS

P4HB mesh was implanted in 121 patients via retrorectus or onlay technique. Physical exam and/or quality of life surveys were completed at 1, 3, 6,12, 18, 24, and 36 months, with 5-year (60-month) follow-up ongoing.

RESULTS

A total of n = 121 patients were implanted with P4HB mesh (n = 75 (62%) female) with a mean age of 54.7 ± 12.0 years and mean BMI of 32.2 ± 4.5 kg/m2 (±standard deviation). Comorbidities included: obesity (78.5%), active smokers (23.1%), COPD (28.1%), diabetes mellitus (33.1%), immunosuppression (8.3%), coronary artery disease (21.5%), chronic corticosteroid use (5.0%), hypo-albuminemia (2.5%), advanced age (5.0%), and renal insufficiency (0.8%). Hernias were repaired via retrorectus (n = 45, 37.2% with myofascial release (MR) or n = 43, 35.5% without MR), onlay (n = 8, 6.6% with MR or n = 24, 19.8% without MR), or not reported (n = 1, 0.8%). 82 patients (67.8%) completed 36-month follow-up. 17 patients (17.9% ± 0.4%) experienced hernia recurrence at 3 years, with n = 9 in the retrorectus group and n = 8 in the onlay group. SSI (n = 11) occurred in 9.3% ± 0.03% of patients.

CONCLUSIONS

Long-term outcomes following ventral hernia repair with P4HB mesh demonstrate low recurrence rates at 3-year (36-month) postoperative time frame with no patients developing late mesh complications or requiring mesh removal. 5-year (60-month) follow-up is ongoing.

The Patenting and Technological Trends in Hernia Mesh Implants

Described as a projection (prolapse) of tissue through a fascial defect in the abdominal wall, hernias are associated with significant rates of complications, recurrence, and reoperations. This literature review is aimed at providing an overview of the prosthetic surgical meshes used for the repairing of hernia defects. The review was carried out using two specialized online databases: Espacenet, from the European Patent Office (EPO), and WIPO from the World Intellectual Property Organization. Of the 56 patents selected from 2008 to 2018, China was the largest contributor with 55% (31 patents) of the total patent applicant filings, followed by the United States of America (US), with 29% (16 patents). Although the majority of patent applications (39 documents) had at least one company (industry) assigned to the patent application, 4 patents were solely from academic research. Our data showed that only 13 industry applicants have had their products included in the market, and the majority of meshes available on the market are still made from polypropylene. Chemical, physical, and mesh surface modifications have been implemented, and a few reviews describing mesh design, composition, and mechanical properties are available. However, to date, the ideal mesh implant from a clinical point of view has not been developed.

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.

Early results of comparison of polypropylene mesh and 75% resorbable mesh (monofilament polypropylene and poly-L-lactic acid (PLLA) mesh) for laparoscopic total extraperitoneal (TEP) inguinal hernia repair

OBJECTIVE

Laparoscopic totally extraperitoneal (TEP) hernia repair has become increasingly widespread. Faster recovery than conventional open methods shortens the return to work. Polypropylene (PP) mesh is still in use in hernia surgery because it is an inexpensive and easily accessible patch. The post-operative chronic pain and foreign body sensation are the disadvantages of these PP patches. Poly-L-lactic acid and polypropylene (PLLA) were used in this study because of the good biocompatibility and low tissue inflammation response. We compared the early clinical outcomes of PP patch and PLLA patches.

METHODS

Between January 2013 and April, 2018,469 patients with inguinal hernia underwent TEP procedure. Patients were divided into two groups. PP mesh (n=211) in group 1, PLLA mesh (n=258) in group 2. Patients were compared regarding age, gender, hernia side, ASA scores, the duration of operation, pain, time to return to work, the sensation of foreign body, seroma and hematoma.

RESULTS

A total of 469 patients were analyzed retrospectively (426 male, 43 female). The mean age was 52.23±13.66 years. The operative times of the patients were 40.92±8.9 minutes in group 1, and 38.82±8.5 minutes in group 2 (p<0.05). The time to return to work was 10.2±1.47 days in Group 1 and 8.4±1.0 days in Group 2 (p<0.05). Visual Analog Scale (VAS) in group 2 was lower than in group 1 (p<0.005). In group 2, the feeling of the organic body decreased in the early and late period (p<0.005). Seroma and hematoma were less in Group 2 than in Group 1 (p<0.005). The mean follow-up period of the patients was 18 (3-63) months, two patients in Group 1, two patients in Group 2 recurred.

CONCLUSION

The PLLA patch used in the TEP method is thought to be a herniated patch that can be safely used because of its ease of application and less postoperative complication rates and more rapid return to work.

Evaluation of resorbable polydioxanone and polyglycolic acid meshes in a rat model of ventral hernia repair

The objective of this study was to evaluate physical, mechanical, and biological properties of the polydioxanone (PDO) monofilament meshes and polyglycolide (PGA) polyfilament meshes in comparison with Permacol^® implants. In rat experimental model, a 1.5 × 2.0 cm defect in abdominal wall was reconstructed by using the Permacol surgical implant or knitted meshes produced from either PDO monofilament, or PGA multifilament. The implant sites were assessed for the tensile strength and the extents of material resorption, host inflammatory response and host tissue replacement on days 3, 10, 30, or 60 after the surgery. The PDO and PGA meshes were rapidly pervaded by the host connective tissue with elements of skeletal muscle histogenesis. The degree of adhesions was significantly higher in the Permacol group. All of the prostheses underwent resorption, which correlated with gradual decreases in the overall tensile strength of the site and the Col1a1 gene expression level. Elevated expression of Fgf2 gene maintained longer in the PDO group, and the Mmp9 gene expression level in this group was higher than in the other groups. Gene expression levels of inflammatory cytokines were higher in the Permacol group. The foreign body giant cell numbers were lower in the PDO and Permacol groups than in the PGA group. Minimal macrophage infiltration with predominance of M2 cells was observed in the PDO group. Overall, the PDO prosthesis turned out to be significantly better than the PGA or Permacol prostheses by a number of indicators of biocompatibility and efficacy. © 2018 The Authors Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 00B: 000-000, 2018. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 652-663, 2019.

A Current Review of Long-Acting Resorbable Meshes in Abdominal Wall Reconstruction

Concern for chronic infection of a permanent synthetic material in contaminated and "high risk" ventral hernia repairs has led to the development and dissemination of slowly resorbable biosynthetic materials at a lower cost compared with biologic mesh counterparts. Here, we review the preclinical and clinical data available for each long-acting resorbable mesh, with a candid comparison to biologic and synthetic equivalents.

Biomaterial Implants in Abdominal Wall Hernia Repair: A Review on the Importance of the Peritoneal Interface

Biomaterials have long been used to repair defects in the clinical setting, which has led to the development of a wide variety of new materials tailored to specific therapeutic purposes. The efficiency in the repair of the defect and the safety of the different materials employed are determined not only by the nature and structure of their components, but also by the anatomical site where they will be located. Biomaterial implantation into the abdominal cavity in the form of a surgical mesh, such as in the case of abdominal hernia repair, involves the contact between the foreign material and the peritoneum. This review summarizes the different biomaterials currently available in hernia mesh repair and provides insights into a series of peculiarities that must be addressed when designing the optimal mesh to be used in this interface.

Mesh implants for hernia repair: an update

INTRODUCTION

Today the use of textile meshes has become a standard for the treatment of abdominal wall hernias and for the reinforcement of any tissue repair as the strength of the implant decreases the recurrence rates. With increasing use, side effects of the textile implants became apparent, as well.

AREAS COVERED

Based on publications in Medline over the past decade, general and specific benefits, as well as risks, are discussed with the challenge to define individual risk-benefit ratios. For meshes, certain high-risk or low-risk conditions can be defined. In an attempt to eliminate mesh-related risks, quality control for medical devices has meanwhile been revised. In both the USA and the EU post-market surveillance studies are required to keep medical devices approved.

EXPERT COMMENTARY

The impact of material on the complication rate will vary depending on the patient's co-morbidity or the risks of the procedure. Even the best material can end up with disappointing results in case of poor healing or poor surgery. On the other hand, when using high-risk devices, most of the complications after excellent surgery with excellent indication can be supposed to be mesh-related. Thus, the use of low-risk devices is recommended even though its advantage may not be demonstrable in clinical studies.

Titanium-coated mesh versus standard polypropylene mesh in laparoscopic inguinal hernia repair: a prospective, randomized, controlled clinical trial

OBJECTIVE

We aimed to compare the clinical outcome of titanium-coated mesh and polypropylene mesh in laparoscopic inguinal hernia repair.

METHODS

A total of 102 patients who received laparoscopic inguinal hernia repair in January-June 2016 in Beijing Chao-Yang Hospital were enrolled in this study. Patients were randomly divided into two groups, receiving either titanium-coated mesh (n = 50) or standard polypropylene mesh (n = 52). Multiple clinical parameters were collected and analyzed, including clinical manifestations, operative time, intraoperative blood loss, hospital stay, hospital cost, recovery time, and postoperative complications.

RESULTS

All procedures were completed. A statistical difference between two groups was not identified in regards to operative time, intraoperative blood loss, hospital stay, and recovery time (P > 0.05). Three cases with seroma and 15 with foreign body sensation were reported in the titanium-coated mesh group; 9 cases with seroma and 17 with foreign body sensation were reported in the standard polypropylene mesh group. There was no significant difference in the incidence of seroma and/or foreign body sensation. A lower hospital cost but longer recovery period was documented in the standard polypropylene mesh group (P < 0.05). No recurrence, infection or chronic pain was observed during 1-year follow-up in both groups.

CONCLUSION

Titanium-coated mesh possesses comparable clinical qualities as the standard polypropylene mesh but with a shorter recovery period. Therefore, this mesh is promising for clinical practice though the cost is higher than the standard polypropylene mesh.

Updates in Mesh and Biomaterials

Prior publications of the Surgical Clinics of North America have highlighted the technical challenges of abdominal wall reconstruction. This article provides an update on synthetic, biologic, and biosynthetic mesh research since the 2013 Surgical Clinics of North America hernia publication and highlights the future of mesh research. This update features research that has been conducted since the prior publication to guide surgeons to choose the best and most appropriate mesh for their patients.

TEP With Long-Term Resorbable Mesh in Patients With Indirect Inguinal Hernia

Background and Objectives:

The role of long-term degradable implants in reducing the risk of chronic postoperative pain after inguinal hernia repair is still unclear. A pilot study using a synthetic long-term resorbable mesh in Lichtenstein repair showed good results regarding pain and discomfort in patients with indirect inguinal hernia (IH) without recurrences, but higher recurrence rate in patients with direct inguinal hernia (DH). The purpose of this study was to assess the incidence of pain and early recurrence in patients with LIH surgically treated with the TEP technique using a long-term degradable mesh. This is the first human study to use long-term degradable mesh with the TEP approach.

Methods:

This study was prospective, including 35 primary IHs surgically treated with TEP repair using TIGR Mesh (Novus Scientific Pte, Ltd, Singapore). At the 1-year follow-up recurrence was assessed by clinical examination and the incidence of pain or discomfort was assessed before and after surgery by Visual Analog Scale (VAS) and Inguinal Pain Questionnaire (IPQ).

Results:

After 12 months, no patients had chronic pain. Only 1 (2.8%) patient reported pain using the VAS (score = 2), and 4 patients reported pain that could easily be ignored. All 4 patients reported less pain 1 year after the operation using both IPQ and VAS, compared with the preoperative assessment. One patient (2.8%) developed a recurrence 20 months after the primary operation.

Conclusion:

TEP repair using a synthetic long-term resorbable mesh was found to be safe and promising regarding pain and discomfort at 1-year follow-up in patients with IH. Longer follow-up is necessary to establish the risk of recurrence.

[Not Available]

Zusammenfassung. Chronische Schmerzen nach Inguinalhernienoperationen sind häufig. Die aktuelle Evidenz zeigt, dass die endoskopische Versorgung von Hernien mit einem Netz chronische postoperative Schmerzen verringert. Dieser Review zeigt mögliche Ursachen und therapeutische Optionen bei Patienten mit chronischen Schmerzen nach Hernienoperationen auf.

Prevention of parastomal hernia in the emergency setting

AIM

This study assessed safety and efficacy associated with hernia prophylaxis using a retromuscular slowly resorbable synthetic mesh for stoma reinforcement.

METHOD

This was a cohort study with a historic reference group. The study took place in a high-volume surgical department. During a 2-year period (July 2012-July 2014), we included 109 patients undergoing emergency surgery with formation of ileostomy or colostomy. All patients received a retromuscular slowly resorbable synthetic mesh (TIGR®, Novus Scientific) at the stoma site. The reference group included 117 patients who underwent emergency stoma formation without a prophylactic mesh in the 2-year period prior to July 2012. The primary endpoint was effect on prevention of parastomal hernia within 1 year. Secondary endpoints were 30-day and 1-year complications including mortality.

RESULTS

The operative field was contaminated or dirty in 48% of the procedures. Operative time was significantly longer in the mesh group. The cumulative incidences of parastomal hernia at 1 year for the control and the mesh group were 8 and 7% (p = 0.424), respectively. The postoperative 30-day and 1-year rate of complications, reoperations and mortality were not different between the two groups. No patients underwent removal of the mesh and no clinical mesh infections were seen.

CONCLUSION

Use of a resorbable synthetic mesh during emergency ostomy formation showed no significant preventive effect on formation of parastomal hernia after 1 year. Although surgery was often conducted in a severely contaminated field, the procedure was without significantly increased complication rate.

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.

Uniformity of Chronic Pain Assessment after Inguinal Hernia Repair: A Critical Review of the Literature

BACKGROUND

Chronic postoperative inguinal pain (CPIP) is the most common long-term complication of inguinal hernia repair. As such procedures are routinely performed, CPIP can be considered a significant burden to global health care. Therefore, adequate preventative measures relevant to surgical practice are investigated. However, as no gold standard research approach is currently available, study and outcome measures differ between studies. The current review aims to provide a qualitative analysis of the literature to seek out if outcomes of CPIP are valid and comparable, facilitating recommendations on the best approach to preventing CPIP.

METHODS

A systematic review of recent studies investigating CPIP was performed, comprising studies published in 2007-2015. Study designs were analyzed regarding the CPIP definitions applied, the use of validated instruments, the availability of a baseline score, and the existence of a minimal follow-up of 12 months.

RESULTS

Eighty eligible studies were included. In 48 studies, 22 different definitions of CPIP were identified, of which the definition provided by the International Association for the Study of Pain was applied most often. Of the studies included, 53 (66%) used 33 different validated instruments to quantify CPIP. There were 32 studies (40%) that assessed both pain intensity (PI) and quality of life (QOL) with validated tools, 41% and 4% had a validated assessment of only PI or QOL, respectively, and 15% lacked a validated assessment. The visual analog scale and the Short Form 36 (SF36) were most commonly used for measuring PI (73%) and QOL (19%). Assessment of CPIP was unclear in 15% of the studies included. A baseline score was assessed in 45% of the studies, and 75% had a follow-up of at least 12 months.

CONCLUSION

The current literature addressing CPIP after inguinal hernia repair has a variable degree of quality and lacks uniformity in outcome measures. Proper comparison of the study results to provide conclusive recommendations for preventive measures against CPIP therefore remains difficult. These findings reaffirm the need for a uniform and validated assessment with uniform reporting of outcomes to improve the burden that CPIP poses to a significant surgical patient population.

Which mesh or graft? Prosthetic devices for abdominal wall reconstruction

This article reviews the ever-increasing number of prosthetic devices--both synthetic mesh and biologic grafts--now in use for abdominal wall reconstruction. It also introduces a novel hybrid synthetic/biologic graft (Zenapro) and suture passer device (Novapass).

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.

Evolution and advances in laparoscopic ventral and incisional hernia repair

Primary ventral hernias and ventral incisional hernias have been a challenge for surgeons throughout the ages. In the current era, incisional hernias have increased in prevalence due to the very high number of laparotomies performed in the 20^th century. Even though minimally invasive surgery and hernia repair have evolved rapidly, general surgeons have yet to develop the ideal, standardized method that adequately decreases common postoperative complications, such as wound failure, hernia recurrence and pain. The evolution of laparoscopy and ventral hernia repair will be reviewed, from the rectoscopy of the 4^th century to the advent of laparoscopy, from suture repair to the evolution of mesh reinforcement. The nuances of minimally invasive ventral and incisional hernia repair will be summarized, from preoperative considerations to variations in intraoperative practice. New techniques have become increasingly popular, such as primary defect closure, retrorectus mesh placement, and concomitant component separation. The advent of robotics has made some of these repairs more feasible, but only time and well-designed clinical studies will tell if this will be a durable modality for ventral and incisional hernia repair.

Emerging Trends in Abdominal Wall Reinforcement: Bringing Bio-Functionality to Meshes

Abdominal wall hernia is a recurrent issue world-wide and requires the implantation of over 1 million meshes per year. Because permanent meshes such as polypropylene and polyester are not free of complications after implantation, many mesh modifications and new functionalities have been investigated over the last decade. Indeed, mesh optimization is the focus of intense development and the biomaterials utilized are now envisioned as being bioactive substrates that trigger various physiological processes in order to prevent complications and to promote tissue integration. In this context, it is of paramount interest to review the most relevant bio-functionalities being brought to new meshes and to open new avenues for the innovative development of the next generation of meshes with enhanced properties for functional abdominal wall hernia repair.