Structure And Mechanical Property Of Flat And Three Dimensional Hernia Mesh With Atlas Structure

The wide use of hernia mesh in hernia hernioplasties decrease the recurrence and pain greatly after surgery, however, ideal outcome has not yet reached. Physical-mechanical property of hernia mesh is the major contributing factor that have impact on recurrence of hernia, the discomfort and life quality of patients. Trade standard for characterization and evaluation system of hernia mesh has not established, the close relationship between evaluation indexes, which can reflect the physiological characteristics of abdominal wall, and structures were not studied in current research. Besides, there is no characterizing method of three dimensional hernia mesh. Therefore, effective evaluation on the strength, elasticity and stiffness of hernia mesh, as well as the analysis of impact of structure on mechanical properties and mechanical characterization of three dimensional mesh will contribute to the establish of comprehensive evaluation system, and provide basic theory for product design with better structure.This study evaluated pore characteristics of several warp knitting hernia meshes and analyzed the impact of structure on it. Besides, the physical-mechanical property of meshes with three-needle open atlas stitch were evaluated and the impact of stitch density on it were analyzed. Finally, the characterizing method of three dimensional hernia mesh were provided, the impact of different test condition on compression performance were analyzed, which will refine the research method for hernia meshes.The results showed that meshes with two-guide bar structure exhibited larger maximum pore area and effective porosity than that with single-guide bar structure, the stitch density and loop morphology will contribute to larger distance of filament and effective porosity of meshes with single-guide bar structure. Hernia mesh with three-needle open atlas stitch exhibited different bending stiffness between different sides, technical back displayed larger bending stiffness than that of technical face. Stitch density had great influence on mechanical anisotropy, breaking strength, tear strength and bending stiffness in longitudinal direction increase with larger wale density, the elongation in longitudinal direction and initial modulus in horizontal direction decreased with larger wale density; breaking strength, tear strength and bending stiffness in horizontal direction increased with larger course density, the elongation in horizontal direction and initial modulus in longitudinal direction decreased with larger course density; suture pull out strength and ball burst strength increased with larger stitch per cm2, the ball burst elongation decreased with larger stitch per cm2. The different value of strength between longitudinal and horizontal direction will be smaller with larger ratio of course density to wale density(K), the different value of elongation and bending stiffness are in opposite to the above law. Furthermore, the tear strength in horizontal direction will be decrease greatly when the loop in that direction were broken. Compression performance reflects the strength, rigidity and elasticity of three dimensional hernia mesh, the diameter of restraining ring is main influencing factor.This study provide basic theory for the design of meshes which possess better compliance with the anisotropy of abdominal wall and more methods of characterization and evaluation in vitro, it was also instructive to clinical application. Additional effective porosity and elasticity under low stress were suggested to given in evaluation in vitro, compression performance were recommended to evaluate the mechanical property of three dimensional hernia mesh. The surgeons should pay more attention to the difference of bending stiffness between technical face and back and direction for placement in surgery. The broken of integral loop in horizontal direction should be avoided when required to be cut by surgeons or in fabrication of pre-shaped mesh. It is suggested that these important features should be marked in product design to give guidance to surgeons.