Three-year results from a preclinical implantation study of a long-term resorbable surgical mesh with time-dependent mechanical characteristics

Evaluation of Electrospun Poly-4-Hydroxybutyrate as Biofunctional and Degradable Scaffold for Pelvic Organ Prolapse in a Vaginal Sheep Model

Pelvic organ prolapse (POP) affects many women, especially after menopause. POP occurs due to the descent of weakened supportive tissue. Current prolapse surgeries have high failure rates, due to disturbed wound healing caused by lower tissue regeneration and estrogen depletion. Absorbable poly-4-hydroxybutyrate (P4HB) knit implants exhibited improved cell and tissue response leading to less complications from prolapse surgery. This study aims to enhance wound healing and improve surgical outcomes by using an electrospun (ES) P4HB scaffold (ES P4HB) that emulates natural tissue structure. Further 17β-estradiol (E2)-a prominent wound healing factor-is incorporated into the scaffold (ES P4HB-E2). Parous Dohne Merino sheep underwent posterior vaginal wall implantation of either P4HB (n = 6) or 17β-estradiol relasing P4HB-E2 (n = 6) scaffolds, or underwent native tissue repair (NTR) (n = 4). Vaginal explants were compared for short-term host response in terms of gross necropsy, histomorphology, biomechanics, tissue-integration, and degradation of P4HB at 3-months post-implantation. Both scaffolds show promising results with enhanced mechanical properties and increased macrophage infiltration compared to NTR, but without differences between scaffolds. Thus, it seems electrospun P4HB scaffolds already improve tissue integration and healing. Further long-term studies are needed before these scaffolds can be used in clinical practice.

Electrospun meshes for abdominal wall hernia repair: Potential and challenges

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

Use of TIGR Synthetic Reabsorable Mesh in Primary Breast Reconstruction

Background

In postmastectomy prosthetic breast reconstruction, materials such as acellular dermal matrix and synthetic meshes are used to support the implant or expander. The authors present a retrospective review of a synthetic TIGR mesh in primary prepectoral breast reconstruction while evaluating safety outcomes.

Methods

This is a retrospective single-surgeon series of adult female cancer patients who underwent TIGR single-stage direct-to-implant reconstruction or 2-stage tissue expander reconstruction with the use of TIGR mesh. Surgical complications including surgical site infection, wound dehiscence, mastectomy flap necrosis, hematoma or seroma requiring operative intervention, and reconstructive failure were monitored.

Results

A total of 49 patients with 86 breast reconstructions were included in the study. All patients had unilateral cancer and underwent reconstruction between May 2023 and March 2024. There were 37 (75.5%) bilateral mastectomies with reconstruction and 12 (24.5%) unilateral mastectomies with reconstruction. The average age of patients was 53.5 years (range: 32-77 y) and body mass index was 25 kg/m2 (range: 19-37 kg/m2). There were 44 direct-to-implant reconstructions and 42 tissue expander reconstructions. From the 86 breast reconstructions, there were 8 complications with an overall complication rate of 9.3%. This included 2 (2.3%) infections, 5 (5.8%) mastectomy skin necroses, and 1 (1.2%) hematoma. There were a total of 3 reconstructive failures requiring mesh and implant removal (3.5%).

Conclusions

We have shown that TIGR mesh has acceptable short-term outcomes in both single-stage and 2-stage implant-based primary breast reconstruction. Future studies should investigate its long-term efficacy, safety, and cost against comparable products.

Bioinspired Asymmetric-Adhesion Janus Hydrogel Patch Regulating by Zwitterionic Polymers for Wet Tissues Adhesion and Postoperative Adhesion Prevention

Asymmetrically adhesive hydrogel patch with robust wet tissue adhesion simultaneously anti-postoperative adhesion is essential for clinical applications in internal soft-tissue repair and postoperative anti-adhesion. Herein, inspired by the lubricative role of serosa and the underwater adhesion mechanism of mussels, an asymmetrically adhesive hydrogel Janus patch is developed with adhesion layer (AL) and anti-adhesion layer (anti-AL) through an in situ step-by-step polymerization process in the mold. The AL exhibits excellent adhesion to internal soft-tissues. In contrast, the anti-AL demonstrated ultralow fouling property against protein and fibroblasts, which hinders the early and advanced stages of development of the adhesion. Moreover, the Janus patch simultaneously promotes tissue regeneration via ROS clearance capability of catechol moieties in the AL. Results from in vivo experiments with rabbits and rats demonstrate that the AL strongly adheres to traumatized tissue, while the anti-AL surface demonstrate efficacy in preventing of post-abdominal surgery adhesions in contrast to clinical patches. Considering the advantages in terms of therapeutic efficacy and off the shelf, the Janus patch developed in this work presents a promise for preventing postoperative adhesions and promoting regeneration of internal tissue defects.

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.

Surgical and Patient-Reported Outcomes After Mastectomy and Implant-Based Prepectoral Reconstruction Using TIGR® Synthetic Mesh

Background Single-stage direct-to-implant (DTI) breast reconstruction after mastectomy has gained popularity over the last decade, thanks to the wide use of biological matrices and synthetic meshes. Despite their high cost, there is no evidence of superior outcome from the biological matrices compared to the synthetic meshes. In this study, we aimed to evaluate our experience with TIGR, a synthetic, long-term absorbable mesh, in mastectomy and immediate breast reconstruction (MIBR) with a focus on patient-reported outcomes (PROMs). Methods This was a single-trust prospective quality improvement study conducted between 2017 and 2019. The main objectives were complication rates including infection, implant loss, and other surgical complications in patients undergoing TIGR mesh-assisted MIBR in the prepectoral plane for either cancer or risk reduction. PROMs were measured using the validated European Organisation for Research and Treatment of Cancer (EORTC) breast questionnaire module. Clinical evaluations were conducted at one week, three weeks, and 12 months postoperatively. All patients provided written consent, and the audit was registered with the Quality Improvement Department of the organization. Results One hundred and twelve meshes were used in 93 patients with a mean age of 49 (24-75) years and a body mass index (BMI) of 23.4 (19.1-29.6). During the follow-up period, complications occurred in 26 patients (28%), including infection in four (4.3%), complete skin flap necrosis in one (1%), partial flap necrosis in three (3.2%), and implant loss in four (4.3%) patients. PROM data from 41 individuals indicated a moderate overall quality of life (82.7%), with high functional domain scores with relatively lower emotional functioning scores. Symptom domains generally scored poorly except for body image and sexual functioning. Conclusion Mastectomy and immediate prepectoral breast reconstruction using TIGR mesh is safe with low major complication rates. It is associated with high functional and quality of life scores but low scores in symptom domains which could be multifactorial. However, limitations due to study type and follow-up duration suggest caution in generalizing findings.

Biodegradable suture development-based albumin composites for tissue engineering applications

Recent advancements in the field of biomedical engineering have underscored the pivotal role of biodegradable materials in addressing the challenges associated with tissue regeneration therapies. The spectrum of biodegradable materials presently encompasses ceramics, polymers, metals, and composites, each offering distinct advantages for the replacement or repair of compromised human tissues. Despite their utility, these biomaterials are not devoid of limitations, with issues such as suboptimal tissue integration, potential cytotoxicity, and mechanical mismatch (stress shielding) emerging as significant concerns. To mitigate these drawbacks, our research collective has embarked on the development of protein-based composite materials, showcasing enhanced biodegradability and biocompatibility. This study is dedicated to the elaboration and characterization of an innovative suture fabricated from human serum albumin through an extrusion methodology. Employing a suite of analytical techniques-namely tensile testing, scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA)-we endeavored to elucidate the physicochemical attributes of the engineered suture. Additionally, the investigation extends to assessing the influence of integrating biodegradable organic modifiers on the suture's mechanical performance. Preliminary tensile testing has delineated the mechanical profile of the Filament Suture (FS), delineating tensile strengths spanning 1.3 to 9.616 MPa and elongation at break percentages ranging from 11.5 to 146.64%. These findings illuminate the mechanical versatility of the suture, hinting at its applicability across a broad spectrum of medical interventions. Subsequent analyses via SEM and TGA are anticipated to further delineate the suture's morphological features and thermal resilience, thereby enriching our comprehension of its overall performance characteristics. Moreover, the investigation delves into the ramifications of incorporating biodegradable organic constituents on the suture's mechanical integrity. Collectively, the study not only sheds light on the mechanical and thermal dynamics of a novel suture material derived from human serum albumin but also explores the prospective enhancements afforded by the amalgamation of biodegradable organic compounds, thereby broadening the horizon for future biomedical applications.

Two-Year Preclinical Evaluation of Long-Term Absorbable Poly-4-hydroxybutyrate Scaffold for Surgical Correction of Pelvic Organ Prolapse

INTRODUCTION AND HYPOTHESIS

Fully absorbable implants may be an alternative to permanent meshes in the correction pf pelvic organ prolapse (POP) as they may reduce adverse events by promoting tissue regeneration and collagen metabolism. This study was aimed at evaluating the long-term host and biomechanical response to a fully absorbable poly-4-hydroxybutyrate (P4HB) scaffold in comparison with polypropylene (PP) mesh.

METHODS

Poly-4-hydroxybutyrate scaffold (n = 16) and PP mesh (n = 16) were surgically implanted in the posterior vaginal wall of parous female Dohne Merino sheep. Vaginal explants were evaluated in terms of gross necropsy, host response (immune response, collagen deposition, tissue regeneration), biomechanics, and degradation of P4HB at 12 and 24 months post-implantation.

RESULTS

Gross necropsy revealed no infection or fluid collection using P4HB or PP. At 12 months, exposures were observed with both P4HB (3 out of 8) and PP (4 out of 8), whereas at 24 months, exposures were observed only with PP (4 out of 8). The tensile stiffness of the P4HB explants was maintained over time despite complete absorption of P4HB. The collagen amount of the vaginal tissue after P4HB implantation increased over time and was significantly higher than PP at 24 months. P4HB scaffolds exhibited significantly lower myofibroblast differentiation than PP meshes at 24 months.

CONCLUSIONS

The P4HB scaffold allowed for gradual load transfer to the vaginal wall and resulted in mechanically self-sufficient tissue. P4HB scaffold had a more favorable host response than PP mesh, with higher collagen content, lower myofibroblastic differentiation, and no exposures at 24 months. P4HB scaffolds have potential as an alternative to permanent implants in treating POP.

Collagen biomaterials promote the regenerative repair of abdominal wall defects in Bama miniature pigs

Due to adhesion and rejection of recent traditional materials, it is still challenging to promote the regenerative repair of abdominal wall defects caused by different hernias or severe trauma. However, biomaterials with a high biocompatibility and low immunogenicity have exhibited great potential in the regeneration of abdominal muscle tissue. Previously, we have designed a biological collagen scaffold material combined with growth factor, which enables a fusion protein-collagen binding domain (CBD)-basic fibroblast growth factor (bFGF) to bind and release specifically. Though experiments in rodent animals have indicated the regeneration function of CBD-bFGF modified biological collagen scaffolds, its translational properties in large animals or humans are still in need of solid evidence. In this study, the abdominal wall defect model of Bama miniature pigs was established by artificial operations, and the defective abdominal wall was sealed with or without a polypropylene patch, and unmodified and CBD-bFGF modified biological collagen scaffolds. Results showed that a recurrent abdominal hernia was observed in the defect control group (without the use of mesh). Although the polypropylene patch can repair the abdominal wall defect, it also induced serious adhesion and inflammation. Meanwhile, both kinds of collagen biomaterials exhibited positive effects in repairing abdominal wall defects and reducing regional adhesion and inflammation. However, CBD-bFGF-modified collagen biomaterials failed to induce the regenerative repair reported in rat experiments. In addition, unmodified collagen biomaterials induced abdominal wall muscle regeneration rather than fibrotic repair. These results indicated that the unmodified collagen biomaterials are a better option among translational patches for the treatment of abdominal wall defects.

A novel self-gripping long-term resorbable mesh providing temporary support for open primary ventral and incisional hernia

A novel synthetic fully long-term resorbable self-gripping mesh has been recently developed to reinforce soft tissue where weakness exists during ventral hernia repair open procedures. This resorbable mesh is a macroporous, knitted, poly-L-lactide, poly-trimethylene carbonate copolymer monofilament mesh with the ProGrip™ technology, providing grips on one side of the mesh. A new poly-L-lactide, poly-trimethylene copolymer was developed to provide the required features for mechanical support during at least 20 weeks covering the critical healing period, including resistance to fatigue under cyclic loading conditions, as it occurs in patients. The yarns and mesh initial physical and biomechanical properties were characterized. Then, the mesh mechanical strength was evaluated over time. The mechanical properties of the proposed mesh were found to be above the generally recognized threshold value to mechanically support the repair site of a hernia over a 20-week period during in-vitro cyclic loading test. The mesh performance was evaluated in vivo using a published preclinical porcine model of hernia repair at 4-, 12- and 20-weeks post implantation. The burst strength of the hernia repair sites reinforced with the new mesh were higher at 4 & 12 weeks and comparable at 20 weeks to the one of the native abdominal walls. At all time points, the mesh was well tolerated with moderate inflammation and was fast integrated in the abdominal wall at 4 weeks. Particularly, the grips were nicely engulfed in the newly formed connective tissue. They must facilitate the anchoring of the mesh by their extension from the mesh and their mushroom shape. The preclinical data of the self-gripping resorbable mesh suggests that it has all the favorable characteristics for future clinical use during ventral hernia repair open procedures.

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.

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.

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.

Prospective, multicenter study of antimicrobial-coated, noncrosslinked, acellular porcine dermal matrix (XenMatrix™ AB Surgical Graft) for hernia repair in all centers for disease control and prevention wound classes: 24-month follow-up cohort

Prospective, multicenter, single-arm study of antimicrobial-coated, noncrosslinked, acellular porcine dermal matrix (AC-PDM) in a cohort involving all centers for disease control and prevention wound classes in ventral/incisional midline hernia repair (VIHR).

Materials and methods

Seventy-five patients (mean age 58.6±12.7 years; BMI 31.3±4.9 kg/m2) underwent ventral/incisional midline hernia repair with AC-PDM. Surgical site occurrence (SSO) was assessed in the first 45 days post-implantation. Length of stay, return to work, hernia recurrence, reoperation, quality of life, and SSO were assessed at 1, 3, 6, 12, 18, and 24 months.

Results

14.7% of patients experienced SSO requiring intervention within 45 days post-implantation, and 20.0% thereafter (>45 d post-implantation). Recurrence (5.8%), definitely device-related adverse events (4.0%), and reoperation (10.7%) were low at 24 months; all quality-of-life indicators were significantly improved compared to baseline.

Conclusion

AC-PDM exhibited favourable results, including infrequent hernia recurrence and definitely device-related adverse events, with reoperation and SSO comparable to other studies, and significantly improved quality of life.

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.

Role of Fibroblasts and Myofibroblasts on the Pathogenesis and Treatment of Pelvic Organ Prolapse

Pelvic organ prolapse (POP) is a multifactorial connective tissue disorder caused by damage to the supportive structures of the pelvic floor, leading to the descent of pelvic organs in the vagina. In women with POP, fibroblast function is disturbed or altered, which causes impaired collagen metabolism that affects the mechanical properties of the tissue. Ideal surgical repair, either native tissue repair or POP surgery using an implant, aims to create a functional pelvic floor that is load-bearing, activating fibroblasts to regulate collagen metabolism without creating fibrotic tissue. Fibroblast function plays a crucial role in the pathophysiology of POP by directly affecting the connective tissue quality. On the other hand, fibroblasts determine the success of the POP treatment, as the fibroblast-to-(myo)fibroblast transition is the key event during wound healing and tissue repair. In this review, we aim to resolve the question of “cause and result” for the fibroblasts in the development and treatment of POP. This review may contribute to preventing the development and progress of anatomical abnormalities involved in POP and to optimizing surgical outcomes.

Evaluation of the short-term host response and biomechanics of an absorbable poly-4-hydroxybutyrate scaffold in a sheep model following vaginal implantation

Objective

To evaluate the host‐ and biomechanical response to a fully absorbable poly‐4‐hydroxybutyrate (P4HB) scaffold in comparison with the response to polypropylene (PP) mesh.

Design

In vivo animal experiment.

Setting

KU Leuven Center for Surgical Technologies.

Population

Fourteen parous female Mule sheep.

Methods

P4HB scaffolds were surgically implanted in the posterior vaginal wall of sheep. The comparative PP mesh data were obtained from an identical study protocol performed previously.

Main outcome measures

Gross necropsy, host response and biomechanical evaluation of explants, and the in vivo P4HB scaffold degradation were evaluated at 60‐ and 180‐days post‐implantation. Data are reported as mean ± standard deviation (SD) or standard error of the mean (SEM).

Results

Gross necropsy revealed no implant‐related adverse events using P4HB scaffolds. The tensile stiffness of the P4HB explants increased at 180‐days (12.498 ± 2.66 N/mm SEM [p =0.019]) as compared to 60‐days (4.585 ± 1.57 N/mm) post‐implantation, while P4HB degraded gradually. P4HB scaffolds exhibited excellent tissue integration with dense connective tissue and a moderate initial host response. P4HB scaffolds induced a significantly higher M2/M1 ratio (1.70 ± 0.67 SD, score 0–4), as compared to PP mesh(0.99 ± 0.78 SD, score 0–4) at 180‐days.

Conclusions

P4HB scaffold facilitated a gradual load transfer to vaginal tissue over time. The fully absorbable P4HB scaffold, in comparison to PP mesh, has a favorable host response with comparable load‐bearing capacity. If these results are also observed at longer follow‐up in‐vivo, a clinical study using P4HB for vaginal POP surgery may be warranted to demonstrate efficacy.

Tweetable Abstract

Degradable vaginal P4HB implant might be a solution for treatment of POP.

Degradable vaginal P4HB implant might be a solution for treatment of POP.

Pliable, Scalable, and Degradable Scaffolds with Varying Spatial Stiffness and Tunable Compressive Modulus Produced by Adopting a Modular Design Strategy at the Macrolevel

Clinical results obtained when degradable polymer-based medical devices are used in breast reconstruction following mastectomy are promising. However, it remains challenging to develop a large scaffold structure capable of providing both sufficient external mechanical support and an internal cell-like environment to support breast tissue regeneration. We propose an internal-bra-like prototype to solve both challenges. The design combines a 3D-printed scaffold with knitted meshes and electrospun nanofibers and has properties suitable for both breast tissue regeneration and support of a silicone implant. Finite element analysis (FEA) was used to predict the macroscopic and microscopic stiffnesses of the proposed structure. The simulations show that introduction of the mesh leads to a macroscopic scaffold stiffness similar to the stiffness of breast tissue, and mechanical testing confirms that the introduction of more layers of mesh in the modular design results in a lower elastic modulus. The compressive modulus of the scaffold can be tailored within a range from hundreds of kPa to tens of kPa. Biaxial tensile testing reveals stiffening with increasing strain and indicates that rapid strain-induced softening occurs only within the first loading cycle. In addition, the microscopic local stiffness obtained from FEA simulations indicates that cells experience significant heterogeneous mechanical stimuli at different places in the scaffold and that the local mechanical stimulus generated by the strand surface is controlled by the elastic modulus of the polymer, rather than by the scaffold architecture. From in vitro experiments, it was observed that the addition of knitted mesh and an electrospun nanofiber layer to the scaffold significantly increased cell seeding efficiency, cell attachment, and proliferation compared to the 3D-printed scaffold alone. In summary, our results suggest that the proposed design strategy is promising for soft tissue engineering of scaffolds to assist breast reconstruction and regeneration.

Feasibility study of oxidized hyaluronic acid cross-linking acellular bovine pericardium with potential application for abdominal wall repair

Bovine pericardium(BP)is one of the biological membranes with extensive application in tissue engineering. To fully investigate the potential clinical applications of this natural biological material, a suitable cross-linking reagent is hopefully adopted for modification. Glutaraldehyde (GA) is a clinically most common synthetic cross-linking reagent. In the study, oxidized hyaluronic acid (AHA) was developed to substitute GA to fix acellular bovine pericardium (ABP) for lower cytotoxicity, aiming to evaluate the feasibility of AHA as a cross-linking reagent and develop AHA-fixed ABP as a biological patch for abdominal wall repair. The AHA with the feeding ratio (1.8:1.0) has an appropriate molecular weight and oxidation degree, almost no cytotoxicity and good cross-linking effect. The critical cross-linking characteristics and cytocompatibility of AHA-fixed ABP were also investigated. The results demonstrated that 2.0% AHA-fixed ABP had the most suitable mechanical properties, thermal stability, resistance to enzymatic degradation and hydrophilicity. Moreover, 2.0% AHA-fixed samples exhibited an excellent cytocompatibility with human peritoneal mesothelial cells (HPMC) and low antigenicity. It also showed a prominent anti-calcification ability required for abdominal wall repair. Our data provided experimental basis for future research on AHA as a new cross-linking reagent and AHA-fixed ABP for abdominal wall repair.

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.

Functionalized Strategies and Mechanisms of the Emerging Mesh for Abdominal Wall Repair and Regeneration

Meshes have been the overwhelmingly popular choice for the repair of abdominal wall defects to retrieve the bodily integrity of musculofascial layer. Broadly, they are classified into synthetic, biological and composite mesh based on their mechanical and biocompatible features. With the development of anatomical repair techniques and the increasing requirements of constructive remodeling, however, none of these options satisfactorily manages the conditional repair. In both preclinical and clinical studies, materials/agents equipped with distinct functions have been characterized and applied to improve mesh-aided repair, with the importance of mesh functionalization being highlighted. However, limited information exists on systemic comparisons of the underlying mechanisms with respect to functionalized strategies, which are fundamental throughout repair and regeneration. Herein, we address this topic and summarize the current literature by subdividing common functions of the mesh into biomechanics-matched, macrophage-mediated, integration-enhanced, anti-infective and antiadhesive characteristics for a comprehensive overview. In particular, we elaborate their effects separately with respect to host response and integration and discuss their respective advances, challenges and future directions toward a clinical alternative. From the vastly different approaches, we provide insight into the mechanisms involved and offer suggestions for personalized modifications of these emerging meshes.

Resorbable self-locking device for canine lung lobectomy: A clinical and experimental study

OBJECTIVE

To test the feasibility of a resorbable self-locking device for sealing of lung tissue in lung lobectomy in experimental dogs and dogs with pulmonary mass, and to study its resorption with CT.

STUDY DESIGN

Experimental study and clinical case series.

ANIMALS

Five beagles in the experimental group; six canine patients with a pulmonary mass in the clinical group.

METHODS

In both groups, an intercostal incision into thorax was performed. A resorbable self-locking device, LigaTie, was applied at the hilum of left cranial lobe in the experimental group and the affected lobe in the clinical group. Each lobe was removed by cutting the tissue just distal to the device. Video-assisted thoracic surgery was used in the experimental group; postoperative diagnostic imaging was repeated monthly until the device was not apparent on CT.

RESULTS

Application of LigaTie was feasible for lung lobectomy in all dogs. The device enabled en bloc ligation of the hilum of the affected lobe including the pulmonary arteries and veins and lobular bronchus. No air leakage from the resection stump was observed in any dog. Trace of the device on CT images gradually decreased and was undetectable at 4 months postoperatively in experimental dogs.

CONCLUSION

This study suggested that the resorbable self-locking device may be used for sealing of airways in complete lung lobectomy.

CLINICAL RELEVANCE

The resorbable self-locking device is suggested to be useful for canine lung lobectomy and may facilitate thoracoscopic lung lobectomy. Further investigations on its clinical application in small animal surgery are warranted.

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.

First-year complications after immediate breast reconstruction with a biological and a synthetic mesh in the same patient: A randomized controlled study

Background

Even though meshes and matrices are widely used in breast reconstruction, there is little high‐quality scientific evidence for their risks and benefits. The aim of this study was to compare first‐year surgical complication rates in implant‐based immediate breast reconstruction with a biological mesh with that of a synthetic mesh, in the same patient.

Methods

This study is a clinical, randomized, prospective trial. Patients operated on with bilateral mastectomy and immediate breast reconstruction were randomized to biological mesh on one side and synthetic mesh on the other side.

Results

A total of 48 breasts were randomized. As the synthetically and the biologically reconstructed breasts that were compared belonged to the same woman, systemic factors were exactly the same in the two groups. The most common complication was seroma formation with a frequency of 38% in the biological group and 3.8% in the synthetical group (p = .011). A higher frequency of total implant loss could be seen in the biologic mesh group (8.5% vs. 2%), albeit not statistically significant (p = .083).

Conclusions

In the same patient, a synthetic mesh seems to yield a lower risk for serious complications, such as implant loss, than a biological mesh.

The Use of Synthetic Mesh in Reconstructive, Revision, and Cosmetic Breast Surgery

BACKGROUND

Recent evidence suggests that the use of acellular dermal matrices in prosthetic breast reconstruction, revision, or augmentation may be associated with an increased risk of complications. In this article we report our results of a potential alternative, using a new long-term resorbable synthetic matrix in these cases.

METHODS

A retrospective study was performed evaluating 11 primary breast reconstructions (19 breasts), 43 secondary reconstructions (77 breasts), 3 augmentation/augmentation mastopexys (6 breasts), and 5 mastopexys (10 breasts) in 62 patients using TIGR^® Matrix Surgical Mesh.

RESULTS

Follow-up ranged from 9.4 to 26.1 months with an average follow-up of 16.5 months. Average age was 54 years. The number of patients who had prior radiation was 9 (14.5 %). Four patients (6.5 %) were smokers. Postoperative breast complications included necrosis of two flaps (1.8 %), two seromas requiring drainage (1.8 %), four infection/extrusions (3.6 %), two relapses of inframammary fold/malposition (1.8 %), and two with rippling (1.8 %). Other complications included six cases of asymmetry that required a corrective procedure. In a variety of breast surgery cases very good aesthetic results were achieved.

CONCLUSION

The long-term absorbable synthetic matrix, TIGR^® Matrix Surgical Mesh, shows potential when used as temporary reinforcement in patients undergoing breast reconstruction or breast surgery revisions and in primary aesthetic procedures, and it appears to be a viable alternative to the use of acellular dermal matrices.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266 .

Drain secretion and seroma formation after immediate breast reconstruction with a biological and a synthetic mesh, respectively: A randomized controlled study

The aim of this study was to compare seroma production in breast reconstruction with a biological mesh with that of a synthetic mesh, in the same patient. The patients were randomized to biological mesh in one breast and synthetical in the other. Twenty-four breasts were included. The total drain production and the daily drain production were similar in the two groups. After drain removal, there were more seroma aspirations in the biological group. During the exchange to a permanent implant, there was significantly more seroma in the biological group. Seroma formation is different in synthetic and biological meshes.

The use of a novel synthetic resorbable scaffold (TIGR Matrix®) in a clinical quality improvement (CQI) effort for abdominal wall reconstruction (AWR)

PURPOSE

The use of hernia mesh is a common practice in abdominal wall reconstruction (AWR) operations. The high cost of biologic mesh has raised questions about the value of its use in AWR. Resorbable synthetic mesh may have the potential benefits of biologic mesh, minimizing the need for removal when infected, at a lower cost.

METHODS

A hernia program has implemented the principles of clinical quality improvement (CQI) to improve patient outcomes. One process improvement attempt was implemented using a newly available resorbable synthetic scaffold. Long-term follow-up was obtained as a part of the CQI process.

RESULTS

A total of 91 patients undergoing AWR were included between 8/11 and 9/15 (49 months). There were 58 female (64%) and 33 male (36%) patients. The average age was 57.2 years (28-80). The average BMI was 34.0 (17.6-53.4). There were 52 patients (57%) with recurrent hernias. Mean hernia defect size was 306.6 cm² (24-720) and mean mesh size was 471.7 cm² (112-600). Outcomes included a mean length of stay of 7.5 days (0-49), a recurrence rate of 12% (11/91) and a wound complication rate of 27% (25/91). The recurrence rate decreased to 4.5% (3/66) after several improvements, including adopting a transversus abdominus release (TAR) approach, were implemented. There were no mesh-related complications and no mesh removal (partial or total) was required. The mean follow-up length was 42.4 months (0-102).

CONCLUSION

In this group of patients, an attempt at process improvement was implemented using a resorbable synthetic scaffold for AWR. With no mesh-related complications and no mesh removals required, there was an improvement in value due to the decrease in mesh cost and improved outcomes over time. Long-term follow-up demonstrated the durability of the repair.

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.

Comparison of inflammatory response and synovial metaplasia in immediate breast reconstruction with a synthetic and a biological mesh: a randomized controlled clinical trial

The aim of this study was to compare inflammatory response and synovial metaplasia in implant-based immediate breast reconstruction with a biological mesh (Veritas^®) with that of a synthetic mesh (TIGR^® Matrix Surgical Mesh). We hypothesize that the inflammatory response and formation of synovial metaplasia might be different and the rate of capsular contracture therefore different. The patients were recruited from the Gothenburg TIGR^®/Veritas^® Study (ClinicalTrials.Gov identifier NCT02985073). All referrals for bilateral immediate breast reconstruction were assessed for inclusions. During the operation, the patients were randomized to which sides the biological and the synthetic mesh were going to be applied. During the implant exchange biopsies were taken. Biopsies were taken from 30 breasts in 15 patients. There seem to be more myofibroblast and neovascularization in the biological meshes than in the synthetic and the collagen fibers seem to be aligned in an irregular pattern with both parallel and vertical fibers. In the synthetic meshes, there were more giant cells and foreign body reaction and the collagen fibers were loosely and well aligned, oriented parallel to the surface of the implant. Synovial metaplasia was seen in the majority of both the biological and the synthetic meshes. The histological patterns in early capsules from biological and synthetic meshes vary considerably. Nonetheless, it is unknown what role different cell types have in capsular formation in the long run and there was no difference in clinical capsular contracture at the clinical follow-up in this study.

The in vivo biocompatibility of titanized polypropylene lightweight mesh is superior to that of conventional polypropylene mesh

OBJECTIVE

To evaluate the histological response to and changes in the biomechanical properties of titanized polypropylene lightweight mesh and conventional polypropylene mesh at 1 and 12 weeks following implantation in the sheep vagina.

METHODS

We compared a titanized polypropylene lightweight mesh (TiLOOP Mesh) to a conventional polypropylene mesh (Gynemesh PS) in a sheep vagina model. Explants were harvested after 1 and 12 weeks (n = 6/mesh type/time point) for histological observation. After 12 weeks, mesh-tissue complex specimens were biomechanically assessed by a uniaxial tension system.

RESULTS

One week after implantation, there was no significant difference in the inflammatory response between the two groups. Twelve weeks after implantation, the TiLOOP light mesh elicited a lower inflammatory response than was observed for the Gynemesh PS (1.44 ± 0.61 vs 2.05 ± 0.80, P = .015). Twelve weeks after implantation, the collagen I/III ratio was lower in the TiLOOP light mesh group than in the Gynemesh PS group (9.41 ± 5.06 vs 15.21 ± 8.21, P = .019). The messenger RNA expression levels of the inflammatory factors interleukin 10 and tumor necrosis factor α were lower in the TiLOOP Mesh group than in the Gynemesh PS group at both 1 and 12 weeks (P < .05). There were no significant differences in any of the evaluated biomechanical characteristics between the two meshes (P > .05).

CONCLUSION

Although the titanized polypropylene lightweight mesh induces slightly less tissue reactivity and has better in vivo biocompatibility, further studies should be conducted including the complications and the success rate of pelvic organ prolapse in patients before recommending it in pelvic floor reconstruction.

Bioresorbable Electronic Implants: History, Materials, Fabrication, Devices, and Clinical Applications

Medical implants, either passive implants for structural support or implantable devices with active electronics, have been widely used for the diagnosis and treatment of various diseases and clinical issues. These implants offer various functions, including mechanical support of biological structures in orthopedic and dental applications, continuous electrophysiological monitoring and feedback of electrical stimulation in neuronal and cardiac applications, and controlled drug delivery while maintaining arterial structure in drug-eluting stents. Although these implants exhibit long-term biocompatibility, surgery for their retrieval is often required, which imposes physical, biological, and economical burdens on the patients. Therefore, as an alternative to such secondary surgeries, bioresorbable implants that disappear after a certain period of time inside the body, including bioresorbable active electronics, have been highlighted recently. This review first discusses the historical background of medical implants and briefly define related terminology. Representative examples of non-degradable medical implants for passive structural support and/or for diagnosis and therapy with active electronics are also provided. Then, recent progress in bioresorbable active implants composed of biosignal sensors, actuators for therapeutics, wireless power supply components, and their integrated systems are reviewed. Finally, clinical applications of these bioresorbable electronic implants are exemplified with brief conclusion and future outlook.

Experimental study of a new original mesh developed for pelvic floor reconstructive surgery

INTRODUCTION AND HYPOTHESIS

Most synthetic meshes used in transvaginal surgery are made of polypropylene, which has a stable performance, but does not easily degrade in vivo. However, mesh-related complications are difficult to address and have raised serious concerns. A new biomaterial mesh with good tissue integration and few mesh-related complications is needed. To evaluate the effect of a new bacterial cellulose (BC) mesh on pelvic floor reconstruction following implantation in the vagina of sheep after 1 and 12 weeks.

METHODS

The meshes were implanted in the submucosa of the posterior vagina wall of sheep. At 1 and 12 weeks after surgery, mesh-tissue complex (MTC) specimens were harvested for histological studies and biomechanical evaluation. At 12 weeks after surgery, MTC specimens were biomechanically assessed by a uniaxial tension "pulley system".

RESULTS

The BC mesh elicited a higher inflammatory response than Gynemesh™PS at both 1 and 12 weeks after implantation. Twelve weeks after implantation, the BC mesh resulted in less fibrosis than Gynemesh™PS. Compared with the Gynemesh™PS group, the BC mesh group had increased mRNA expression of MMP-1, MMP-2, and MMP-9 (P < 0.05), but decreased expression of the anti-inflammatory factor IL-4 (P < 0.05). Twelve weeks after implantation, the ultimate load and maximum elongation percentage of the BC mesh were significantly lower than those of Gynemesh™PS.

CONCLUSIONS

The BC mesh could not be a promising biomaterial for pelvic floor reconstructive surgery unless the production process and parameters were improved.

A biological or a synthetic mesh in immediate breast reconstruction? A cohort-study of long-term Health related Quality of Life (HrQoL)

OBJECTIVES

Meshes/matrices are commonly used in immediate breast reconstruction. There are few studies comparing biological and synthetic meshes and it is unknown what type of mesh gives the best long-term results. The aim of this study was to compare long-term health-related quality of life (HrQoL) and patient satisfaction in implant-based immediate breast reconstruction with a biological mesh (Surgisis^®) with that of patients reconstructed with a synthetic mesh (TIGR ^® Matrix Surgical Mesh).

MATERIAL AND METHODS

Both cohorts were prospectively included and consecutively operated. Clinical data was collected. HrQoL was evaluated with EuroQoL-5 dimension - 3 levels questionnaire (EQ-5D-3L) and the Hospital Anxiety and Depression Scale (HADS) and the Breast-Q.

RESULTS AND CONCLUSION

Seventy-one patients were operated on in the biological group and 49 in the synthetic group. The response rates were 75 and 84 per cent, respectively. Mean follow-up time was 74 months and 23 months, respectively. There were no statistical differences in satisfaction and quality of life between the two groups. Complications and radiation seem to lead to a lower satisfaction. Our findings could indicate that biological and synthetic meshes give an equal long-term result as regards patients' perceived quality of life.

Comparison of macroscopic resorption time for a self-locking device and suture material in ovarian pedicle ligation in dogs

A resorbable self-locking device (LigaTie) was developed to enable safe and easy surgical ligation of blood vessels. The aim of this study was to compare the long-term in vivo resorption of the device to a commercially available suture of equivalent material (Maxon) following ovarian pedicle ligation. After ovariohysterectomy follow-up ultrasound examinations were performed monthly on 21 dogs ligated with the device and 22 dogs ligated with the suture material until no hyperechoic remnants, acoustic shadowing or local tissue reactions were detected. In both groups, the ovarian pedicles gradually decreased in size. Ligation material was considered macroscopically resorbed when ultrasound showed no signs of the device or suture, ovarian pedicle or tissue reaction. Macroscopic resorption had occurred without signs of complications and was complete by four months for sutures and 5.5 months for the device. The results show that resorption time in vivo for the resorbable self-locking device is mildly longer than suture of the same material and that no complications of device resorption were detected, supporting that the resorbable self-locking device is safe for in vivo use.

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.

[Acellular dermal matrix and synthetic mesh in implant-based immediate breast reconstruction: Current concepts]

The use of acellular dermal matrices and synthetic meshes is gaining popularity in direct-to-implant breast reconstruction, allowing the complete coverage of the prosthesis with greater pocket control and improved cosmesis. In this concise review, we present the advantages of acellular dermal matrices and resorbable or nonresorbable synthetic meshes in implant-based breast reconstruction, we discuss the risk of postoperative complications, and we raise their contribution in the growing interest of prepectoral breast reconstruction.

"Complex abdominal wall" management: evidence-based guidelines of the Italian Consensus Conference

To date, there is no shared consensus on a definition of a complex abdominal wall in elective surgery and in the emergency, on indications, technical details, complications, and follow-up. The purpose of the conference was to lay the foundations for a homogeneous approach to the complex abdominal wall with the primary intent being to attain the following objectives: (1) to develop evidence-based recommendations to define “complex abdominal wall”; (2) indications in emergency and in elective cases; (3) management of “complex abdominal wall”; (4) techniques for temporary abdominal closure. The decompressive laparostomy should be considered in a case of abdominal compartment syndrome in patients with critical conditions or after the failure of a medical treatment or less invasive methods. In the second one, beyond different mechanism, patients with surgical emergency diseases might reach the same pathophysiological end point of trauma patients where a preventive “open abdomen” might be indicated (a temporary abdominal closure: in the case of a non-infected field, the Wittmann patch and the NPWT had the best outcome followed by meshes; in the case of an infected field, NPWT techniques seem to be the preferred). The second priority is to create optimal both general as local conditions for healing: the right antimicrobial management, feeding—preferably by the enteral route—and managing correctly the open abdomen wall. The use of a mesh appears to be—if and when possible—the gold standard. There is a lot of enthusiasm about biological meshes. But the actual evidence supports their use only in contaminated or potentially contaminated fields but above all, to reduce the higher rate of recurrences, the wall anatomy and function should be restored in the midline, with or without component separation technique. On the other site has not to be neglected that the use of monofilament and macroporous non-absorbable meshes, in extraperitoneal position, in the setting of the complex abdomen with contamination, seems to have a cost effective role too. The idea of this consensus conference was mainly to try to bring order in the so copious, but not always so “evident” literature utilizing and exchanging the expertise of different specialists.

TIGR® matrix surgical mesh - a two-year follow-up study and complication analysis in 65 immediate breast reconstructions

In recent years, it has become increasingly popular to use matrices, such as acellular dermal matrices, in implant-based breast reconstruction. To lower the cost and to avoid implanting biological material, the use of synthetic meshes has been proposed. This is the first study examining TIGR^® Mesh in a larger series of immediate breast reconstruction. The aims of the study were to examine complications and predictors for complications. All consecutive patients operated on with breast reconstruction with TIGR^® Matrix Surgical Mesh and tissue expanders (TEs) or permanent implant between March 2015 and September 2016 in our department were prospectively included. Exclusion criteria were ongoing smoking, BMI (kg/m²) > 30, planned postoperative radiation, and inability to leave informed consent. Fifteen breasts (23%) were affected by complications within 30 d: four (6.2%) major complications and eleven (17%) minor complications. The major complications included two implant losses and one pulmonary embolism (PE). Predictors for a complication were age over 51 years, BMI over 24.5 kg/m², large resection weight, and the need for a wise pattern excision of skin. Four minor surgical complications occurred after 30 d (minimum follow-up 17 months). There were no implant losses. In addition, minor aesthetic corrections, such as dog-ear resection, were performed in 10 breasts. In conclusion, breast reconstruction with a TE in combination with TIGR^® Matrix Surgical Mesh can be performed with a low complication rate.