Finite element analysis of fibre-reinforced constitutive formulation of Cadisc-L

The current study measures the mechanical behavior of both natural and the monobloc elastomeric disc prosthesis (CadiscTM-L) by employing a finite element method (FEM) to study the fiber-reinforced constitutive formulation provided in the literature. The three-dimensional geometry was created by computed tomography (CT) scan imaging technique.
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Finite element analysis of fibre-reinforced constitutive formulation of Cadisc-L Engineering Solid Mechanics 7 (2019) 151-162 Contents lists available at GrowingScience Engineering Solid Mechanics homepage: www.GrowingScience.com/esmFinite element analysis of fibre-reinforced constitutive formulation of Cadisc-LAli Ansaria, Hamidreza Ghasemi Bahrasemanb*, Morteza Mohssenzadehc, MohammadHaghpanahia, Kamran Hassania and Hossein Derakhshandehda Department of Biomechanics, Science and Research Branch, Islamic Azad University, Tehran, Iranb Mechanical Engineering Department, San Diego State University, San Diego, 92182, CA, USAc Mechanical Engineering Department, University of San Diego, San Diego, 92110, CA, USAd Department of Mechanical & Material Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USAA R T I C L EI N F O ABSTRACT Article history: The current study measures the mechanical behavior of both natural and the monobloc elastomeric Received 10 October, 2018 disc prosthesis (CadiscTM-L) by employing a finite element method (FEM) to study the fiber- Accepted 24 December 2018 reinforced constitutive formulation provided in the literature. The three-dimensional geometry was Available online created by computed tomography (CT) scan imaging technique. Frontal pure rotational, sagittal, 24 December 2018 Keywords: and axial momentum of 7.5 N·m were applied on the top of L3 while the lower half of the L5 was Cadisc-L fixed in all directions. This investigation was performed considering two stages: (1) intact L3–L5 Finite element method lumbar spine (INT model), and (2) Cadisc implemented between L4 and L5 (IMP model). The Fibre-reinforced constitutive numerical results for the INT model were validated by experimental data from the literature. formulation Several parameters including the inter-segmental rotation, range of motion in flexion-extension, axial rotation and lateral bending were analyzed. Our numerical results show that the IMP model has a 50% reduction in the ‘range of motion’ and a 33% reduction in flexion in lateral bending compared to the INT model. These outcomes of this paper reveal the feasibility of applying a fibre- reinforced constitutive formulation to generate an accurate three-dimensional FEM model. © 2019 Growing Science Ltd. All rights reserved.1. IntroductionDespite progresses in prevention, diagnosis, and treatment of intervertebral disc problems, suchproblems remain a main cause of disability for humans (Joshi et al., 2006). Elderly people, after theappearance of instability in their spinal column, may suffer from pain due to the degeneration ofintervertebral discs and they usually need implantation with an artificial disc (Dietrich et al., 2005).Discovering the effect of geometry and tissue properties is challenging in the numerical modelingapproaches due to the high intrinsic parameters existing in the experiment (Berkson et al., 1979;Nachemson et al., 1979; Skultz et al., 1979). Furthermore, a major limitation of in-vitro explorations isquantification of load transfer between different tissues that are constrained by range of motionincluding global reaction forces and intradiscal pressure. Computational methods, however, have thepotential to determine the biomechanical behavior of natural and artificial intervertebral discs byeliminating the need for experimental procedures provided that their procedures meet validationcriteria.* Corresponding author. Tel. : +1-901-567-8750 E-mail addresses: hghasemibahraseman@sdsu.edu (H. Ghasemi Bahraseman)© 2019 Growing Science Ltd. All rights reserved.doi: 10.5267/j.esm.2018.12.004152 The finite element method is widely used for strain and stress analysis of engineering structuresparticularly in biomechanics and proved to be very functional for complex models of living tissuesstructures (Amerian et al., 2014; Bahraseman et al., 2013, 2014a, 2014b, 2015 & 2016; Dietrich et al.,1991; Kedzior et al., 1996; Khosravi et al., 2014a & 2014b; Poor et al., 2017; Sabooni et al., 2015;Skalli, 1999; Zienkiewicz & Taylor, 1991). These computational tools provide assistance for a betterinterpretation of clinical and experimental data to improve the prosthesis design. The Cadisc-L isproduced from a polyurethane-polycarbonate polymer using stiff endplates. The internal structure ofCadisc-L consists of a soft nucleus encircled by a stiffer annulus that is segregated by a gradualtransition of modulus (Naylor et al., 2012; Gwynne et al., 2010; Gwynne & Cameron, 2010; Barnes etal., 2012). The advantage of having separated regions is to eliminate sharp interfaces among materials withdifferent mechanical properties (Gwynne & Cameron, 2010). The design of the implant nearly imitatesthe mechanical properties of the natural disc (Naylor et al., 2012; Gwynne et al., 2010; Johnson et al.,2011; Benzel et al., 2011). Langrana et al. (1 ...