P044 ATRAUMATIC AND CONSISTENT HERNIA MESH FIXATION: PERFORMANCE AND SAFETY IN A LAPAROSCOPIC IPOM PORCINE MODEL

Aim Demonstrate the performance and safety of TISSIUM on-demand activated adhesive for atraumatic hernia mesh fixation in a laparoscopic IPOM porcine model. Material and Methods Full thickness 4 cm in diameter excisional abdominal defects (n = 14) were created in pig (n = 8). The defects were repaired through laparoscopic intraperitoneal mesh placement using commercial composite meshes fixed with TISSIUM adhesive (n = 8) or resorbable tacks (n = 6). The animals were sacrificed after 28 and 90 days. An independent pathologist evaluated abdominal adhesion, mesh shrinkage, local tissue tolerance and tissue ingrowth through histological analysis (H&E and Movat Pentacrome) at sacrifice. Fixation strength of the explanted abdominal walls was also assessed via burst-ball. Results No adverse events were observed at implantation or during the survival period. All the meshes were in place at sacrifice. Mesh shrinkage and abdominal adhesion scores were similar between the two groups. Histological analysis of the mesh demonstrated equivalent quality of tissue ingrowth and excellent local tissue tolerance with minimal/mild foreign body response and mononuclear cells inflammation. The repair strength, evaluated through a burst ball method 90 days after implantation, showed no significant difference between the TISSIUM adhesive and tacks. Usability is currently being evaluated in clinically relevant models. Conclusions In this preclinical study the TISSIUM adhesive demonstrated similar fixation strength and quality of repair when compared to commercial tacks. This technology has the potential to impact hernia procedures standardization and reduce pain often associated with current fixation technologies.

P046 ATRAUMATIC AND CONSISTENT HERNIA MESH FIXATION: PERFORMANCE AND SAFETY IN A LAPAROSCOPIC IPOM PORCINE MODEL

Aim Demonstrate the performance and safety of TISSIUM on-demand activated adhesive for atraumatic hernia mesh fixation in a laparoscopic IPOM porcine model. Material and Methods Full thickness 4 cm in diameter excisional abdominal defects (n = 14) were created in pig (n = 8). The defects were repaired through laparoscopic intraperitoneal mesh placement using commercial composite meshes fixed with TISSIUM adhesive (n = 8) or resorbable tacks (n = 6). The animals were sacrificed after 28 and 90 days. An independent pathologist evaluated abdominal adhesion, mesh shrinkage, local tissue tolerance and tissue ingrowth through histological analysis (H&E and Movat Pentacrome) at sacrifice. Fixation strength of the explanted abdominal walls was also assessed via burst-ball. Results No adverse events were observed at implantation or during the survival period. All the meshes were in place at sacrifice. Mesh shrinkage and abdominal adhesion scores were similar between the two groups. Histological analysis of the mesh demonstrated equivalent quality of tissue ingrowth and excellent local tissue tolerance with minimal/mild foreign body response and mononuclear cells inflammation. The repair strength, evaluated through a burst ball method 90 days after implantation, showed no significant difference between the TISSIUM adhesive and tacks. Usability is currently being evaluated in clinically relevant models. Conclusions In this preclinical study the TISSIUM adhesive demonstrated similar fixation strength and quality of repair when compared to commercial tacks. This technology has the potential to impact hernia procedures standardization and reduce pain often associated with current fixation technologies.

DESIGN AND DEVELOPMENT OF IMPURITIES FREE PYROLYTIC COATED MECHANICAL BI-LEAFLET HEART VALVE PROTOTYPE

Heart valve problems affect more than 100 million people worldwide. According to statistics, around 55% of valvular diseases are treated by a mechanical prosthesis. The first heart valve replaced model was the caged-ball valve, more than 50 models of heart valves designed by different companies. Each design has different aspects such as valve geometry, leaflets design, materials used for model manufacturing, coating techniques, and coating materials. Depending on the patient's need and condition, the native heart valve either replaced by a biological or mechanical heart valve. Biological valves are made of living tissues whereas mechanical valves manufactured by the biomaterials, which are biocompatible and do not causes any reaction inside the body. The prototype discussed in this paper provides good hemocompatibility, because of the biomaterial used in this prototype manufacturing. It will reduce tissue ingrowth, due to the enhanced leaflet ear of the orifice ring. Moreover, it will cause less thrombotic effects into the host due to greater contact angel of graphite and smooth surface of graphite after pyrolytic coating. The significant evolution of mechanical valve designs consists of valve geometry, coating technique, and materials. In this research, the 3D-CAD model of Bileaflet Mechanical Mitral Heart Valve was designed using SOLID WORKS 2016 and fabricated by 5-axis Computer Numeric Control (CNC) machine. Graphite was used for the fabrication of prototype and Pyrolytic Carbon (PyC) coating was performed with Chemical Vapor deposition (CVD) technique. Scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Diffraction (XRD) were used to determine the effects of CVD on surface topography and chemical structure of graphite model before and after coating. Furthermore, hemocompatibility of graphite and PyC analyzed through in-vitro hemolytic activity. The Characterization results showed that the Bileaflet Mechanical Mitral Heart valve prototype after PyC coating provides a smooth surface with improved hemocompatibility and less adhesion. Besides, the Mechanical Heart valves showed no hemolysis during the hemolytic activity. By virtue of its smooth and nonporous surface, it is antithrombotic and provides good hemodynamics. The advance long leaflet ear design reduces the tissue ingrowth around the orifice which will further limit the leaflets movement.

Developing a Hernia Mesh Tissue Integration Index Using a Porcine Model—A Pilot Study

Introduction: With so many prosthetics available, it can be difficult for surgeons to choose the most appropriate hernia mesh. Successful hernia repair mandates an understanding of how the patient's inflammatory response influences surgical outcomes. Failure to appreciate the importance of the biological aspect of hernia repair can be very costly as emerging evidence supports that biofilm formation and reduction in effective mesh porosity gives rise to long-term mesh complications including fibrosis, chronic mesh infection, and pain. In this pilot study, we utilized a large animal (porcine) model to develop a numerical Mesh Tissue Integration (MTI) Index focused on visible tissue ingrowth, fibrosis, adhesion formation and resorption of mesh. The aim is to help surgeons adopt an evidence-based approach in selecting the most appropriate mesh according to its tissue ingrowth characteristics, matched to the patient to achieve improved surgical outcomes and optimal patient-centered care.Methods: Two forty kg female Landrace pigs were recruited for this pilot study. A total of eight commonly used hernia mesh products and two controls measuring 5 × 5cm were surgically implanted in subrectus and intraperitoneal planes. The pigs were euthanised at 2 and 4 weeks, respectively. The abdominal wall was explanted, and the mesh specimens underwent macroscopic, histologic and biomechanical analysis, with engineering and pathology teams blinded to the mesh.Results: Significant differences between the degrees of MTI were observed at 2 weeks and the distinctions were even more apparent at 4 weeks. One of the interesting incidental findings we observed is that mesh products placed in the subrectus plane displayed greater degrees of adhesion strength and integration than those placed intraperitoneally.Conclusion: This pilot study is one of the first to propose a functional, biological standardized model for comparing hernia mesh products. The results are encouraging and demonstrate that this is a robust and transferrable model for assessing MTI in hernia mesh. The intention for this model is that it will be utilized synergistically with long term mesh/patient outcome registries and databases to inform improved matching of mesh to patient, particularly in the setting of the complex hernia repair and abdominal wall reconstruction.

Resorbable membrane of polyethylene glycol in Wistar rats for guided bone regeneration - Experimental study

Purpose: The aim of the present study was (1) to test whether or not the application of an in situ formed synthetic hydrogel, made of polyethylene glycol (PEG) used as a resorbable membrane for guided bone regeneration, will result in more amount of bone regeneration compared with an uncovered defect and (2) to evaluate if it can prevent the soft-tissue ingrowth into alveolar defects. Materials and Methods: Two critical size defects were created in seven Wistar rats. In the right side, an in situ formed hydrogel PEG membrane (Straumann MembraGel) was applied into the defect and the left one was kept empty as a control. After 60 days, animals were sacrificed and the calvarial bone was removed. The area of newly formed bone was determined by histomorphometrical analysis. For statistical analysis, the Mann-Whitney-U test was applied to model the amount of new bone formation. Results: The quantitative histomorphometric analysis obtained a percentage of newly formed bone for the test defects of 61,8% +/-22,2% and 53,8% +/-22,9% in the control group. The observed differences were not statistically significant. Conclusions The experimental PEG membrane was biocompatible and prevented soft-tissue ingrowth. There were no statistically significant differences between the groups.

Multiple polyurethane implant punctures during fat grafting: case report and review of the literature

Background Breast augmentation with implants continues to be the most popular aesthetic surgical procedure performed worldwide. Fat grafting may improve the results of breast augmentation and breast reconstruction with implants. However, fat grafting to the breast with implants carries the risk of implant puncture. To our best knowledge this is the first case in which polyurethane implant puncture during fat grafting is described. Case presentation We report multiple bilateral implant punctures with the cannula during fat grafting in a patient who previously underwent breast reconstruction with polyurethane implants. Conclusions Implants that promote tissue ingrowth may be more prone to puncture with the cannula during fat grafting. Specific planning and surgical maneuvers decrease the risk of implant puncture. Level of evidence Level V, case report.

Bio-Integration and Bone Fixation Performance of Continuous Mineral Fiber-Reinforced Implants

Category: Basic Sciences/Biologics; Other Introduction/Purpose: The integration of an implant into surrounding tissue as remodeling occurs is a characteristic associated with bone grafts or bone fillers, some of which are osteoconductive or osteostimulative. Many bioabsorbable polymer implants lack quiescent degradation and are associated with adverse inflammation. Recently, new bio-integrative bone fixation implants comprised of continuous mineral fibers and polymer were introduced. The implant’s high mineral content is intended to encourage an increased bio-integrative response, while the continuous fiber structure provides mechanical bone fixation strength. The study objectives were to evaluate the implant’s long-term bio-integration and ability to maintain fixation in a load bearing in- vivo model. Methods: Twenty-four rabbits were studied over 104-week period to evaluate the bio-integration of fiber-reinforced bone fixation pins. The continuous reinforcing mineral fibers made up approximately 50% of the implant, comprised of elements found in native bone, including calcium, silica, and magnesium. The other 50% was comprised of poly (L-lactide-co-D, L lactide) (PLDLA) at a 70:30, L:DL ratio. Pins were implanted bilaterally, with three fiber-reinforced pins (test) implanted into the mid-shaft of one femur and three PLDLA polymer pins (control) into the mid-shaft of the other femur. Implantation sites were scored histologically at multiple timepoints to assess bio-integration by means of implant degradation profile, surrounding bone quality and tissue ingrowth. A separate group of twelve rabbits was studied clinically, radiographically and histologically over 12 weeks to evaluate the fiber-reinforced implant performance, compared to a stainless-steel implanted group, in a lateral femur condyle osteotomy model under full load bearing conditions. Results: At 104 weeks, implant material fully eliminated in 11 out of 12 fiber-reinforced implants and in 6 out of 12 PLDLA implants. The fiber-reinforced group showed increased propensity for bio-integration throughout the course of the study, demonstrating a gradual degradation profile and much higher score of tissue ingrowth. Amount of polymer decreased from a score of 4.0 at 4 weeks to score 1.7 at week 26, score 1.0 at week 78 and 0.1 at 104 weeks. The polymer control underwent abrupt late stage degradation, with amount of polymer dropping from a score of 4.0 to 0.7 from 78 to 104 weeks. In the load bearing osteotomy model, the fiber-reinforced implants performed comparable to stainless-steel, demonstrating tighter bone-to- implant interface with no intervening fibrotic tissue. Conclusion: This study represents the first long term in-vivo evaluation of mineral fiber-reinforced implants demonstrating both bio-integration and orthopedic fixation. Quiescent bio-integration is a significant challenge for degradable orthopedic fixation implants. The implants must be mechanically strong for stable fixation while able to gradually integrate with surrounding bone without adverse effects. Continuous fiber reinforced implants proved the unique potential to meet this challenge with a fiber structure that provides fixation strength and is comprised entirely of minerals found in native bone. An increased level of mesenchymal tissue ingrowth, combined with the absence of local or systemic adverse response, demonstrates excellent bio- integration.