480711 Computational Model of Soft Tissue Interaction with Prosthetic Mesh

Monday, November 14, 2016
Grand Ballroom B (Hilton San Francisco Union Square)
Tysum Ruchti, Mechanical Engineering, Brigham Young University, Provo, UT and Arnab Chanda, Aerospace Engineering and Mechanics, University of Alabama, Tuscaloosa, AL

A hernia occurs when an organ or fatty tissue squeezes through a hole or a weak spot in the surrounding muscle or connective tissue. Hernias mostly occur at the abdominal wall, and could also take the form of Pelvic Organ Prolapse (POP) in women. A prosthetic mesh is a net-like woven material which is surgically implanted to provide additional support to weakened or damaged tissue. Surgical repair of hernia with mesh have been found to cause pain, infection, organ perforation, mesh migration and mesh shrinkage (contraction). To date, to understand mesh failure mechanics, uniaxial, biaxial and cyclic load tests have been conducted on dry and wet meshes. Also, extensive experimental studies have been conducted on animal models to understand the effect of mesh stiffness, pore size, and knitting patterns on the mesh biocompatibility. However, the actual mechanics of mesh interactions with a tissue in presence of sutures has been overlooked. This is the key to understanding how a mesh fails when implanted inside the body. A finite element model of a prosthetic surgical mesh has been constructed based on a repeating cell. The cell geometry was obtained through microscopic imaging. The final mesh is numerically sutured to a block representing organ tissue. Using this model we simulated uniaxial loading on the entire system by applying a forced displacement. This model was used to explore the relationship between mesh stiffness and max tissue stresses. Additionally stress distributions within the tissue and the mesh were examined. Finally the deformation of the system over the range of displacements was recorded. The displacement correlated with physical tests were both show a twisting in the mesh at larger strains. Additionally we were able to visualize different strain patterns between meshes of varying stiffness with the stresses more evenly distributed with lower stiffness.

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