Biomechanics of Bone / Bone Biomechanics
Mohammad Nikkhoo; Ali Tahassori; Mohammad Haghpanahi
Volume 8, Issue 3 , September 2014, , Pages 203-212
Abstract
To develop the advanced technologies in medical device industry, design and manufacturing of cervical cage was performed in Iran for the first time. This research-based industrial project should be accomplished based on precise biomechanical studies and mechanical tests. Hence, this study presents the ...
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To develop the advanced technologies in medical device industry, design and manufacturing of cervical cage was performed in Iran for the first time. This research-based industrial project should be accomplished based on precise biomechanical studies and mechanical tests. Hence, this study presents the optimization and biomechanical functional investigations of the first Iranian cervical cage (Manufactured by Attila Ortopaed Co.). For this purpose the intact cervical spine (C2-C7) was developed and was validated with in-vitro experiments. Three inputs (i.e. geometrical parameters of the cage) and two outputs (i.e. deformation of the teeth in static and dynamic tests) parameters were selected for optimization procedure. Furthermore, the surgery in C5-C6 level was simulated by implanting the cervical cage. Finally, the biomechanical responses were investigated. The result confirmed that the biomechanical response of cervical cage is within the standard range and can be used well in clinics for surgical procedures.
Tissue Engineering
Zahra Saghaei Noosh Abadi; Atefe Aghajani; Mohammad Haghpanahi
Volume 7, Issue 1 , June 2013, , Pages 1-11
Abstract
We introduce how we may produce an experimental phantom for modeling the mechanical properties of soft tissue. Gelatin materials are used to construct the phantom. Our phantom comprises of two different types of tissue; tumor and background normal tissue. Weight ratio of the dry gelatin and deionized ...
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We introduce how we may produce an experimental phantom for modeling the mechanical properties of soft tissue. Gelatin materials are used to construct the phantom. Our phantom comprises of two different types of tissue; tumor and background normal tissue. Weight ratio of the dry gelatin and deionized water are obtained for producing the young’s modulus of 21 kPa and 102 kPa for the normal tissue and tumor, respectively. This phantom is used in ultrasound elastography with external excitation less than 5%.
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.
Tissue Engineering
Mohammad Haghpanahi; Mohammad Nikkhoo; Habibollah Peirovi
Volume 2, Issue 1 , June 2008, , Pages 47-56
Abstract
According to mechanobilogical studies as an infrastructure for tissue engineering researches, this paper presents a triphasic finite element modeling of intervertebral discs such a hydrated porous soft tissue. First, the governmental equations were derived on the basis of the laws of continuum mechanics. ...
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According to mechanobilogical studies as an infrastructure for tissue engineering researches, this paper presents a triphasic finite element modeling of intervertebral discs such a hydrated porous soft tissue. First, the governmental equations were derived on the basis of the laws of continuum mechanics. Then the standard Galerkin weighted residual method was used to form the finite element model. The implicit time integration schemes were applied to solve the nonlinear equations. The formulation accuracy and convergence for one dimensional case were examined with Simon's and Sun's analytical solutions and also Drost's experimental Data. It was shown that the mathematical model is in excellent agreement and has the capability to simulate the intervertebral disc response under different types of mechanical and electrochemical loading conditions. Finally, to have a short review of the capability of the model, a homogenous two dimensional version of the model was applied to simulate the response of a simple sagittal slice of the intervertebral disc.
Biomechanics of Bone / Bone Biomechanics
Mohammad Haghpanahi; Mehdi Pourdanial
Volume 1, Issue 4 , June 2007, , Pages 289-299
Abstract
A 3D anatomically accurate finite element model of the human first cervical vertebra (atlas), including cortical and cancellous bones, was developed in ANSYS 9 based on CT-scan images. The main objective was to investigate the effect of cancellous bone on the value and distribution of maximum and average ...
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A 3D anatomically accurate finite element model of the human first cervical vertebra (atlas), including cortical and cancellous bones, was developed in ANSYS 9 based on CT-scan images. The main objective was to investigate the effect of cancellous bone on the value and distribution of maximum and average Von Mises stress in Atlas. The results showed that the material property of cancellous bone has no significant effect on the location of maximum stress and the pattern of average stress distribution in anterior arch, the junction of posterior arch and lateral mass and the groove of the posterior arch. Although the presence of cancellous bone in the model yielded higher values for the maximum and average stresses. The boundary condition had a considerable effect on this increase. Altering the material property of cancellous bone under neutral and hyperextension loading configurations, affected the average stress only in cancellous bone in the lateral mass, but change in the material property of cortical bone resulted in average stress change both in the cortical and cancellous bones, and in the lateral displacement of the lateral mass as well. The interconnected effects of changing the material properties of these two bone tissues were also studied.
Biomechanics of Bone / Bone Biomechanics
Mohammad Haghpanahi; Ali Gorginzadeh; Saba Sohrabi
Volume 1, Issue 2 , June 2007, , Pages 131-136
Abstract
Considering the life threatening consequences of the cervical spine injuries, the study of its biomechanical behavior has become important. The most common axis (second cervical vertebra) injury is called odontoid fracture, the majority of which is type II or dens fracture. In this study, an exact 3D ...
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Considering the life threatening consequences of the cervical spine injuries, the study of its biomechanical behavior has become important. The most common axis (second cervical vertebra) injury is called odontoid fracture, the majority of which is type II or dens fracture. In this study, an exact 3D finite element model of axis was developed and analyzed. To evaluate the stress distributions in the odontoid process during type II injuries, pressure loads were applied on the dens at locations where it is likely to come into contact with the surrounding neck construct. Results indicate stress concentration in the odontoid junction with the vertebral body, which suggests that there is a possibility of occurring type II fracture in the case of impaction of odontoid with atlas anterior arch, lateral masses and transverse ligament.
Biological Computer Modeling / Biological Computer Simulation
Zohre Barani; Mohammad Haghpanahi; Hamid Reza Katouzian; Hasan Saeidi
Volume -1, Issue 2 , June 2005, , Pages 111-116
Abstract
Current research in foot biomechanics includes studies on prevention of recurrence of neuropathic foot ulcers. This prescribes accommodative insoles, which reduce plantar pressure levels particularly under the hallux. There is little quantitative information available regarding the effects of insole ...
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Current research in foot biomechanics includes studies on prevention of recurrence of neuropathic foot ulcers. This prescribes accommodative insoles, which reduce plantar pressure levels particularly under the hallux. There is little quantitative information available regarding the effects of insole materials. The insole models available in the literature are mostly two- dimensional (2-D). Hence, there is a need to develop a three-dimensional (3-D) model with actual geometry which includes sufficient details. In this study a 3-D model of the insole was constructed. A linear and non-linear static analysis using finite element method (FEM) was done. To construct the 3-D finite element model, 14736 nodes and 16170 elements were used. This research has shown that Silicone Gel is very effective in terms of reduction of stress concentrations. The techniques used in this research provide a promising approach to understand the behavior of insole material as well as a guideline in the design of therapeutic footwear and orthoses for insensate feet.
