Journal of biomechanics
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Journal of biomechanics · May 2020
Effects of nucleus pulposus location on spinal loads and joint centers of rotation and reaction during forward flexion: A combined finite element and Musculoskeletal study.
The mechanical environment of the intervertebral disc and spinal loads are intimately associated with low back pain (LBP) caused by mechanical load. The cause and effect relationship between postures and pain has been therapeutically investigated and widely used to guide patient care. Shift of the nucleus pulposus (NP) inside the intervertebral disc when the spine changes posture in the sagittal plane, known also as NP migration, has been observed and quantified in in-vivo studies. ⋯ The results showed that intradiscal pressure (IDP) and compressive force are sensitive to the nucleus location while the effects on the center of rotation (CoR), center of reaction (CTR) and moment rotation curves were negligible. Also, our findings revealed that FE models should consider the effects of NP location during bending to predict more realistic results as the nucleus displacement caused by disc bulge predicted by these models is much smaller than the real shift observed in in-vivo. In addition, this study confirmed that position of the rigid joint in MSK models that fix this latter to the CoR, must be modelled carefully for more accurate muscle forces and spinal loads prediction.
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Journal of biomechanics · May 2020
Finite element analysis of MitraClip procedure on a patient-specific model with functional mitral regurgitation.
Mitral valve (MV) repair with the MitraClip device has been shown to reduce mitral regurgitation severity and improve clinical outcomes in symptomatic patients at high surgical risk. MitraClip was recently approved in the US for the treatment of functional mitral regurgitation (FMR), which significantly expands the number of patients that can be treated with this device. This study aims to quantify the morphologic changes and evaluate the biomechanical interaction between the MitraClip device and the mitral apparatus of a real patient case with FMR using computational modeling. ⋯ Anterior and posterior leaflet peak stresses increased by up to 64% and 62% after clip placement, respectively, and were located at the region of clip grasp. Similarly, anterior and posterior leaflet peak strains increased by up to 20% and 10%, respectively. FE modeling, as used here, can be a powerful tool to examine the complex MitraClip-host biomechanical interaction.