Studying the Mechanical Behavior of Tissue in the Generation of Pressure Sores using Simulation and a Guinea Pig Experimental Model

Introduction:  Pressure  sores  refer  to  lesions  that  are  produced  while  a  constant  pressure  causes  necrotic  tissue to grow. The need for a better comprehension of the process has led researchers to artificial generation  of  pressure  sores.  Modeling  the  mechanical  behavior  of tissue  will  provide  a better understanding  of this  process as well as a more suitable selection of system parameters.  Materials and Methods: In this research, the mechanical behavior of tissue was modeled using the finite  element method. A system with pressure sensors and a suitable feedback mechanism was used to generate  pressure  sores.  The  elastic  parameters  of  tissue  were  obtained  using  uniaxial  tensile  strength  tests.  The  thicknesses of skin layers were calculated by taking microscopic images of skin samples and using Motic  Images 2000 version 1.2 software.   Results: The results of the finite element modeling illustrate the strain and stress profiles in tissue layers. The  maximum values of deviatory strain occurred under the border of the disc in the muscle layer. Deviatory and  shear stresses reached their maximum values under the center of the disc in the skin layers.   Discussion and Conclusion: The simulation and experimental results are in good agreement. Therefore, the  introduced model may be used for better comprehension of tissue behavior. Better results may be obtained by  finding a more accurate method for calculating tissue parameters.