PhD Student Eric Kramer (MechEngr'16) dissects tissue in the Advanced Medical Technologies Laboratory
Only twelve out of over one-hundred听papers that appeared in the ASME Journal of Biomechanical Engineering, were selected by the editorial board to be published as one of the Journal of Biomechanical Engineering Editors' Choice papers for 2018.听
One such paper,听鈥�A small听deformation thermoporomechanics finite element model and its application听to arterial tissue fusion鈥� was written by Mechanical Engineering professors and graduate students, including PhD student Doug Fankell, PhD student Eric Kramer, Associate Professor Ginger Ferguson听and Associate Professor Mark Rentschler, along with听Civil, Environmental, and Architectural Engineering Associate Professor Rich Regueiro.听
An excerpt from this paper is听included below.听
Introduction
Biological tissue undergoes thermal loading in several manners听ranging from surgical devices that heat or cool biological tissue to听cauterize or ablate it, to natural causes such as hyperthermia听or frostbite. Scientists and physicians seek to understand听these听processes and their impact on tissue mechanics to create novel,听safer, and more effective medical devices and procedures. With听tissue鈥揹evice interaction becoming ever more prevalent in the听form of more complex medical devices, wearable electronics, and听implanted electronics, experimental testing is becoming increasingly听expensive in time and resources. Computer simulations of听these interactions, when calibrated to experimental data, provide听essential insight into the underlying physics occurring in biological听tissue听when deformed and heated, allowing for streamlined听design work and ultimately more effective devices and safer procedures.听Additionally, models with the ability to accurately and听quickly predict surgical outcomes will help satisfy the growing听desire for patient specific, near real time, simulations for surgical听procedures.听
A good deal of biological tissue is nonhomogenous and typically听contains several materials, often in different phases. For听example, the artery wall has an extracellular matrix (ECM) made听up of collagen, elastin, and glycosaminoglycans. While water is听attracted to molecules within the tissue through polar interactions,听it readily moves through interstitial spaces. Thus, this tissue can听be considered as a porous medium. Studies attempting to model听biological tissue,听including vertebral disks, articular cartilage, lung tissue, arterial tissue, skin, tumor, and听myocardial tissue听as a porous medium exist throughout literature;听however, these attempts have failed to completely represent听the complex physics听occurring within the tissue. Typically, models听representing biological tissue as porous media fall into one of听two categories. The first neglects deformation and only heat and/or mass transfer is represented. The second category of听models uses solid mechanics and mass transport to model tissue听deformation and coupled pore fluid flow, but thermal transport is听not considered. To the authors鈥� knowledge, no model听exists that demonstrates the coupled solid phase (ECM) mechanics,听mass transfer, and heat听transfer (thermoporomechanics听(TPM)) occurring in biological tissue. In this paper, a small deformation,听TPM finite element (FE) model with the ability to represent听the heating and deformation of biological tissue is presented,听and its results are validated by comparison听to measured听 experimental听results of thermal arterial tissue fusion.听
听