Biomedical Engineering and Bioengineering Commons^™

Improving Quantification Of Mitral Regurgitation Through Computational Fluid Dynamics And Ex Vivo Testing, Alexandra Flowers

Electronic Theses and Dissertations

Mitral regurgitation (MR) is a prominent cardiac disease affecting more than two million people in the United States alone. In order for patients to receive proper therapy, regurgitant volume must first be quantified. As there are an array of methods to do so, the proximal isovelocity surface area (PISA) method continues to be the most accurate and clinically used method. However, there are some difficulties obtaining the necessary measurements need for this when performing transthoracic echocardiography. This study aims to evaluate and present techniques that may be used to more accurately quantify regurgitation through ex vivo testing and computational fluid …

Pulmonary Valve Replacement, Mina Shafiei

Electronic Theses and Dissertations

Currently, transcatheter pulmonary valve replacement (TPVR) is a well-established alternative for surgical pulmonary valve replacement (SPVR) to treat pulmonary valve disorders in patients with prior congenital heart surgery. Edwards Sapien 3 valve is a bioprosthesis originally designed for the aortic position but has been used off-label in native right ventricular outflow tract (RVOT). It is currently under clinical trial to get food and drug administration (FDA) approval.

This study is a comparison of the performance of Sapien 3 with surgical bioprosthetics. The in vitro tests result showed Sapien 3 experiences less degree of opening and effective orifice area in pulmonic …

Revision Total Hip Femoral Stem Micromotion And Statistical Shape Modeling Of The Knee, William Fugit

Electronic Theses and Dissertations

The first purpose of this thesis was to compare the amount of micromotion seen in the femoral stem in a revision total hip arthroplasty between simple loading conditions and loading conditions derived from activities of daily living, through the use of experimental and computational methods. The amount of micromotion at the bone-implant interface was larger for activities of daily living, with ranges of 200μm more than the largest simple loading conditions. The second purpose of this thesis was to compare measurements of accuracy in a statistical shape model between individual bone and joint-level models, specifically for the knee. Using computational …

Correlating With Local Variation In Collagen Level And Mechanical Properties Of The Heart Tissues, Talayeh Tavangar

Electronic Theses and Dissertations

The determination of the myocardium's tissue properties is essential in constructing finite element (FE) models of the heart. To obtain accurate results, especially for functionally modeling the heart, we must determine the tissue properties in-vivo. The calculation of the heart tissue properties remains a challenging area as it is categorized as a heterogeneous, anisotropic, nonlinear soft tissue that undergoes large deformation. In this work, we tried to introduce and evaluated a finite element method to determine the mechanical properties of the cardiac tissue. The introduced method combined a finite element modeling with the experimentally obtained images from the left and …

Tibial Strains And Tray-Bone Micromotions After Total Knee Arthroplasty: Computational Studies Evaluating The Tibial Fixation, Huizhou Yang

Electronic Theses and Dissertations

Cemented and cementless fixation in total knee arthroplasty (TKA) have been successfully used for decades. As the number of younger and more active patients treated with TKA continues to increase, long-term implant survivorship is of increasing importance. One of the most common complications and hence the reason for revision is mechanical loosening (23.1% of all revised TKA). The loosening mechanisms have been proposed for different fixation types. For cemented fixation, bone remodeling after surgery is regulated by the changes in strain energy density (SED). The recruitment of osteoclasts and osteoblasts is controlled by SED-related signals. Insufficient stimuli can promote bone …

Fluid Dynamics Characterization Of Transcatheter Aortic Valves, Mohammed Barakat

Electronic Theses and Dissertations

Aortic stenosis due to degenerative calcific aortic valvular disease is the most reason for aortic valve replacement in developed countries. Aortic stenosis affects up to 7% of the world population, and current clinical data indicate that the number of the affected people could be triple by 2050, due to population ageing and health lifestyle. Transcatheter aortic valve replacement (TAVR) was introduced as a minimal invasive treatment of severe aortic stenosis. Even though surgical aortic valve replacement (SAVR) is considered the golden standard treatment for severe aortic stenosis patients, TAVR showed equivalent or even superior outcome compare to SAVR. Currently, transcatheter …

Mechanical Effects Of Surgical Adhesives On Ascending Thoracic Aortic Aneurysm Replacement, Dong Qiu

Electronic Theses and Dissertations

Ascending thoracic aortic aneurysm (aTAA) is a potentially lethal disease which grows gradually over time and may lead to aortic dissection and rupture. Currently, aTAA surgical repair using Dacron graft is a well-established treatment. In addition, surgical adhesives are frequently used in the surgeries to seal the anastomotic site. This study aims to investigate mechanical effects of four commonly used surgical adhesives, namely BioGlue, CoSeal, Crosseal, and Tisseel, on the suture site using in-vitro digital image correlation (DIC) method and finite element (FE) simulations in an ovine model. In this study, first, mechanical properties of ovine ascending aorta were obtained …

Development Of A Computational Approach To Assess Hip Fracture And Repair: Considerations Of Intersubject And Surgical Alignment Variability, Azhar Ali

Electronic Theses and Dissertations

Hip fracture remains a major public health concern due to the significant number of occurrences and mortality rates. Intertrochanteric fractures are the most common type of fracture and are typically caused by a fall. Intramedullary osteosynthesis is a common surgical practice to repair intertrochanteric fractures, but revisions are often required. The work presented in this thesis aims to improve the realism and fidelity of computational models of hip fracture, which can be an effective alternative to costly and labor-intensive clinical in-vivo and experimental in-vitro testing. Intersubject variability is inherently present in anatomy and material relations. Statistical shape and intensity models …