The Evolution Of Structure And Properties Of Explanted Hernia Meshes

Hernia is one of the most common abdominal diseases.In recent years,the life quality of patients after mesh repair operation has improved and the reoperation rate of hernia repair has been reduced with the hernia repair techniques and mesh materials development,But after mesh implant into the human body for several months or even more than several years,the biological compatibility and physicochemical stability of the hernia mesh materials often change,which relates to some complications such as hernia recurrence,wound infection,seroma,chronic pain,mesh erosion,mesh adhesion and so on.If that situation become very dangerous to patient,the mesh should be partial excised or total removed from hernia ring,then affect patient's physical and mental health seriously,as well as make a highly cost,so research on the structure and properties changes of explanted hernia meshes and explore the meshes repair failure mechanism are necessarily for put forward good advices to optimize mesh structure and further for mesh production.The study explored preservation impacts on the explants and the best method to clean the typical explanted hernia meshes and researched meshes structure and physicochemical properties change mechanisms,as well as histology analysis of tissue sections.The explants often be preserved initially after removed from human body for together research and analysis.In this study,firstly,10%(v/v)formalin solution was used to test whether it would make impact on tissue morphological characteristics and PP and partially absorbent materials physical features or not.Secondly,the study based on mesh-tissue relationship of explants,compared the physicochemical properties changes of meshes washed with different kinds of methods,then chose the best scheme which has no hurt for the mesh,besides,the scheme was used to wash the clinical explant to test whether it can remove the adhesive tissue effectively.Further,the study focused on research textile structure and physicochemical properties changes of light PP explanted meshes of animal experiment and clinical PP/Silicone and PP/e PTFE composite explanted meshes.The results showed as follows:(1)The tissue volume and color changed to some extent after soaked in 10%(v/v)formalin solution for certain time.The PPDO 3-0 monofilament surface crazed after soaked in the situation for two months,which manifested formalin situation is not suitable for absorbable material preservation though PP/Silicone/e PTFE materials have good stabilities in it.(2)PP meshes cleaned with 5%(w/w)sodium carbonate solutions at 80? had no physical and chemical properties change,meanwhile,the clean method removed the adhesive tissue on the hernia explants effectively.(3)The research on light pp explanted meshes showed two experimental meshes(E1,E2)and other two meshes(U,S)had no significant changes on physicochemical properties compared to virgin meshes,but all shrinkage to a certain degree respectively(12.13%,14.25%,15.13%,3.92%)after implanted in rats for two weeks,The results suggested that the shape and size of mesh pores may be the main reasons for meshes shrinkage and its stability can be optimized through better design.(4)Research on PP/Silicone composite mesh explants indicated that most of the human ventral tissue grew on the surface of polypropylene(PP)fibers side.As for silicone side,tissue only grew into the holes of mesh and cause partial adhesions form.Mesh-tissue interaction makes the mesh shrank rate up to 49.89%.After removal of human tissue,further SEM characterization shows that there were many cracks on the surface of explanted PP fibers,but the silicone side maintains pristine structure.Moreover,the results of DSC and TGA show that the thermal stability of PP fibers are reduced.The carbonyl peaks representing the oxidation of the polypropylene fibers are not shown in the ATR-FTIR results,comparatively,the chemical stability of silicone is good.Histopathological analysis showed that some inflammatory cells appeared around the polypropylene fibers,but the overall inflammation was not significant.The results indicate that the main reasons of the patient hernia recurrence include PP fibers degradation,and the silicone side holes adhesions,and the significant mesh shrink.Meanwhile,the results suggest that as for the mesh,there should be less holes and smaller hole aperture,as well as bigger fibers spacing.(5)Research on PP/e PTFE composite mesh explants indicated that hernia repair outcomes with typical CK meshes had individual difference.Histopathological sections showed that many inflammatory cells appeared around the polypropylene fibers and some fibrosis and necrotic tissue could be found.With implantation time increasing,the transverse fissures on the pp fibers turned to bulky debris and almost fall off,ATR-FTIR results suggests there had carbonyl stretching vibration bands in the functional groups and manifested the pp fibers were oxidized.In conclusion,the study mainly researched the best method to remove adhesive tissue of hernia explants and the structure and properties evaluation of animal experimental and clinical hernia explanted meshes,which can provide methodologies for other types explanted meshes analysis,the structure and properties change mechanism and the idea to adjust fiber assembly density and less holes and smaller hole aperture distribution of the mesh can provide reference advices for new generation superior meshes design.