An analytical model of intervertebral disc mechanics

McNally, Donal; Arridge, R.G.C.

doi:10.1016/0021-9290(95)80007-7

Cited by 24 publications

(7 citation statements)

References 30 publications

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“…4. The simulated results for distribution of fluid pressure are consistent with the experimental findings [53]. At the initial condition (no load), the fluid pressure in the NP is about 0.40 MPa, which is generated due to the higher osmolarity in the disk than that in the ambient environment, and the pressure is equilibrated by the tension of solid matrix.…”

Section: Creep Testsupporting

confidence: 84%

“…The fluid pressure decreases to 1.18 MPa after 4 hrs of creep test. McNally and Arridge [53] reported that the fluid pressure is about 1.70 MPa in a healthy L4-5 disk under 1392 N compressive load. By linearly scaling the fluid pressure with the fraction of compressive loads, the fluid pressure under 1000 N compressive load in the experiment would be 1.22 MPa, which is close to our simulated fluid pressure in the NP (1.18-1.33 MPa).…”

Section: Creep Testmentioning

confidence: 99%

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An Anisotropic Multiphysics Model for Intervertebral Disk

Gao

Zhu

2015

Journal of Applied Mechanics

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Intervertebral disk (IVD) is the largest avascular structure in human body, consisting of three types of charged hydrated soft tissues. Its mechanical behavior is nonlinear and anisotropic, due mainly to nonlinear interactions among different constituents within tissues. In this study, a more realistic anisotropic multiphysics model was developed based on the continuum mixture theory and employed to characterize the couplings of multiple physical fields in the IVD. Numerical simulations demonstrate that this model is capable of systematically predicting the mechanical and electrochemical signals within the disk under various loading conditions, which is essential in understanding the mechanobiology of IVD.

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Section: Creep Testsupporting

confidence: 84%

Section: Creep Testmentioning

confidence: 99%

An Anisotropic Multiphysics Model for Intervertebral Disk

Gao

Zhu

2015

Journal of Applied Mechanics

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“…Stretching of the annulus fibresmay occur underthe application of tensile forces to the annulus or through the hydrostaticpressure exertedbythe nucleus on the annulus under axiall oads (7, 20-22). Undert he application of bending moments (flexion, exten-sion, or lateralbending),the fibresofthe annulus arecompressed towards the direction of the bending,whereas in the opposite direction,the fibresare in tension (20,23,24). The discf ibres ares tretchedi nt he compressed region because of disc bulgingdue to hydrostaticpressure of the nucleus pulposusand in the tensileregion because of direct tensile forces acting on the annulus fibrosus (21,22).…”

Section: Introductionmentioning

confidence: 99%

Intradiscal pressure in the degenerated porcine intervertebral disc

Holm

Ekström²,

Holm³

et al. 2007

Vet Comp Orthop Traumatol

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Measuring intradiscal pressure is one way of mechanically assessing the discs degenerative state. In this study, the load-bearing capacity of degenerated and their adjacent lumbar intervertebral discs was evaluated using two different injury models. Seventeen adolescent pigs were divided into two groups, an annulus injury group and an endplate injury group. The annulus injury group was subjected to a stab incision in the L3-L4 disc, whereas the endplate injury group received a cranial endplate perforation of the L4 vertebral body. Both groups were biomechanically evaluated three months later using a miniaturized servohydraulic testing machine across L2-L4 and with two pressure needles inserted into the nucleus pulposus of the L2-L3 and L3-L4 discs. Linear relationships between the intradiscal pressure and the applied load were determined within the load range studied. When comparing the ratio of the injured to the adjacent disc pressure, the endplate injury was lower (mean value 0.31) than the annulus injury (mean value 0.51). The pressures in the discs adjacent to the degenerated level were found to be slightly higher. This increase can be expected due to a redistribution in mobility demands in segments adjacent to those with increased stiffness, i.e. degenerated intervertebral discs.

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“…Among the few published analytical studies, there are those based on the theory of thick-walled cylinders (Hickey and Hukins, 1980, Hukins, 1992, PrudHomme, 2008, the thin-shell theory (Demers et al, 2013, McNally andArridge, 1995), the theory of laminated plates (Iatridis and ap Gwynn, 2004) and force equilibrium in a series of fiber sheets (Ngwa and Agyingi, 2011). Analytical modeling may appear restrictive to simulate biomechanical tissues, but is yet promising for modeling IVDs, particularly using thin-shell theory.…”

Section: Introductionmentioning

confidence: 99%

Analytical evaluation of stresses and displacements of an intervertebral disc

Demers¹,

Nadeau

Bouzid

2017

JBSE

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Understanding the intervertebral disc response to mechanical loads is important to prevent back injuries. The experimental and the finite element methods are widely used for that purpose but methodological triangulation is deficient due to lack of a complementary method. This study aims at choosing theories and assumptions that could be used to develop an analytical model for stress analysis of intervertebral discs. Thin-shell and beam-onelastic-foundation theories are used in conjunction with an iterative method to account for large deformation of the disc. The model simulates an axial compression load acting on a simplified axisymmetric disc composed of a multi-shell linear and isotropic structure surrounding a pressurized cavity. The highly deformable lamellae are idealized by either circular or parabolic arches in the sagittal plane, and their effect on stress and strain response are compared. The circumferential and longitudinal stresses are compared to those of a simplified finite element model. The comparison shows that the analytical approach is promising and allows to identify improvements for future studies. The use of a parabolic profile is advantageous and allows to account for the interactive support of the lamellae near the endplates. The method should be adapted to improve bulge deformation obtained across the thickness of anulus fibrosus, and the model should include material anisotropy and hyperelasticity.

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An analytical model of intervertebral disc mechanics

Cited by 24 publications

References 30 publications

An Anisotropic Multiphysics Model for Intervertebral Disk

An Anisotropic Multiphysics Model for Intervertebral Disk

Intradiscal pressure in the degenerated porcine intervertebral disc

Analytical evaluation of stresses and displacements of an intervertebral disc

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