Spinal Biomechanics
Iraj Dehghan Hamani; Navid Arjmand
Volume 11, Issue 4 , February 2018, , Pages 327-335
Abstract
Spinal diseases are prevalent and costly. Excessive mechanical loads on the spine play a crucial role in the etiology of back disorders. To estimate spinal loads one needs to calculate unknown muscle forces through either an optimization or EMG-driven approach. Both approaches involve several assumptions ...
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Spinal diseases are prevalent and costly. Excessive mechanical loads on the spine play a crucial role in the etiology of back disorders. To estimate spinal loads one needs to calculate unknown muscle forces through either an optimization or EMG-driven approach. Both approaches involve several assumptions and simplifications regarding anatomy of muscles, mechanical properties of the spinal tissues, and estimation of the muscle forces. An alternative approach is to estimate spinal loads through effect of muscle forces, i.e., kinematics generated by muscles rather than forces generated by muscles. The present study hence aims to estimate spinal loads using a detailed finite element (FE) model of the T12-S1 spine driven by kinematics obtained through upright x-ray imaging. For this, kinematics (angular and translational displacements) of the T12 through S1 vertebrae were first measured in vivo in three healthy individuals when performing flexion from relaxed upright posture. The measured kinematics were subsequently prescribed to the FE model to estimate load sharing among the joint structures. In agreement with the measured data, the L1-L2, L2-L3, L3-L4 and L4-L5 average intradiscal pressure was estimated to be ~2.6, ~2.8, ~2.1 and ~2 MPa in flexion, respectively.
Biomechanics of Bone / Bone Biomechanics
Mohammad Nikkhoo; Mohammad Haghpanahi; J. L. Wang; Mohammad Parnianpour
Volume 5, Issue 1 , June 2011, , Pages 21-32
Abstract
Prediction of the relationship between different types of mechanical loading and the failure of the intervertebral disc is so important to identify the risk factors which are difficult to study in vivo and in vitro. On the basis of finite element methods some of these issues may be overcome ...
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Prediction of the relationship between different types of mechanical loading and the failure of the intervertebral disc is so important to identify the risk factors which are difficult to study in vivo and in vitro. On the basis of finite element methods some of these issues may be overcome enabling more detailed assessment of the biomechanical behavior of the intervertebral disc. The objective of this paper is to develop a nonlinear axisymmetric poroelastic finite element model of lumbar motion segment and show its capability for studying the time-dependent response of disc. After comparison of the response of different models in quasi-static analysis, the poroelastic model of intervertebral disc is presented and the results of short-term, long-term creep tests and cyclic loading were investigated. The results of the poroelastic model are in agreement with experimental ones reported in the literature. Hence, this model can be used to study how different dynamic loading regimes are important as risk factors for initiation of intervertebral disc degeneration.
Cardiovascular Biomechanics
Hamed Khalesi; Hanie Niroomand Oscuii; Farzan Ghalichi
Volume 5, Issue 2 , June 2011, , Pages 143-149
Abstract
Prediction of the relationship between different types of mechanical loading and the failure of the intervertebral disc is so important to identify the risk factors which are difficult to study in vivo and in vitro. On the basis of finite element methods some of these issues may be overcome enabling ...
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Prediction of the relationship between different types of mechanical loading and the failure of the intervertebral disc is so important to identify the risk factors which are difficult to study in vivo and in vitro. On the basis of finite element methods some of these issues may be overcome enabling more detailed assessment of the biomechanical behavior of the intervertebral disc. The objective of this paper is to develop a nonlinear axisymmetric poroelastic finite element model of lumbar motion segment and show its capability for studying the time-dependent response of disc. After comparison of the response of different models in quasi-static analysis, the poroelastic model of intervertebral disc is presented and the results of short-term, long-term creep tests and cyclic loading were investigated. The results of the poroelastic model are in agreement with experimental ones reported in the literature. Hence, this model can be used to study how different dynamic loading regimes are important as risk factors for initiation of intervertebral disc degeneration.
