Analysis of compressive creep behavior of the vertebral unit subjected to a uniform axial loading using exact parametric solution equations of Kelvin-solid models—Part II. Rhesus monkey intervertebral joints

Kaleps, Ints; Kazarian, Leon E.; Burns, M.L.

doi:10.1016/0021-9290(84)90130-1

Cited by 18 publications

(6 citation statements)

References 3 publications

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“…However, for the three-parameter model data from the initial minute were not included in the error analysis, partly due to very few data points, thus giving a gross underestimation of the actual modelling error. Kaleps et al (29) performed a similar in uitro experiment using rhesus monkey motion segments. Mean errors of 14.40 and 1.36 per cent were reported for the two-and three-Q IMechE 1996 parameter solid models respectively.…”

Section: Discussionmentioning

confidence: 99%

Intervertebral Disc Response to Cyclic Loading—An Animal Model

Ekström

Kaigle

Hult

et al. 1996

Proc Inst Mech Eng H

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The viscoelastic response of a lumbar motion segment loaded in cyclic compression was studied in an in vivo porcine model (N = 7). Using surgical techniques, a miniaturized servohydraulic exciter was attached to the L2-L3 motion segment via pedicle fixation. A dynamic loading scheme was implemented, which consisted of one hour of sinusoidal vibration at 5 Hz, 50 N peak load, followed by one hour of restitution at zero load and one hour of sinusoidal vibration at 5 Hz, 100 N peak load. The force and displacement responses of the motion segment were sampled at 25 Hz. The experimental data were used for evaluating the parameters of two viscoelastic models: a standard linear solid model (three-parameter) and a linear Burger's fluid model (four-parameter). In this study, the creep behaviour under sinusoidal vibration at 5 Hz closely resembled the creep behaviour under static loading observed in previous studies. Expanding the three-parameter solid model into a four-parameter fluid model made it possible to separate out a progressive linear displacement term. This deformation was not fully recovered during restitution and is therefore an indication of a specific effect caused by the cyclic loading. High variability was observed in the parameters determined from the 50 N experimental data, particularly for the elastic modulus E1. However, at the 100 N load level, significant differences between the models were found. Both models accurately predicted the creep response under the first 800 s of 100 N loading, as displayed by mean absolute errors for the calculated deformation data from the experimental data of 1.26 and 0.97 percent for the solid and fluid models respectively. The linear Burger's fluid model, however, yielded superior predictions particularly for the initial elastic response.

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Section: Discussionmentioning

confidence: 99%

Intervertebral Disc Response to Cyclic Loading—An Animal Model

Ekström

Kaigle

Hult

et al. 1996

Proc Inst Mech Eng H

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“…Reviews of mechanical characteristics of the lumbar motion segment Kaleps et al, 1984;Kazarian, 1972Kazarian, , 1975Panjabi and White, 1978;Schultz, 1974;Tencer and Ahmed, 19811 show that it is viscoelastic, absorbs energy, moves with six degrees of freedom (three translations and three rotations), exhibits coupled motion (motion in one direction affects motion in others), has limited fatigue tolerance, and depends upon its bony and ligamentous components for mechanical tasks.…”

Section: Mechanical Characteristicsmentioning

confidence: 98%

The biomechanics of vibration and low back pain

Wilder¹

1993

American J Industrial Med

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This work is a review of the mechanical factors related to low back pain production in a vibration environment. The sitting posture is an extreme orientation for the lumbar intervertebral disc that 1) increases its internal pressure, 2) increases its anteroposterior shear flexibility, while: 3) decreasing its resistance to buckling instability and 4) stressing the posterior region of the disc. Vibration is an additional mechanical stressor. Several studies suggest that the following preventive measures be taken to reduce the risk of low back pain due to driving: 1) minimize the vibration reaching the driver, 2) avoid lifting or bending immediately following driving, and 3) walk around for a few minutes following driving.

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“…For the analysis of the dynamic response of the disk, we have used a Voight based linear model to compute the stiffness and damping parameters for the disk. Although the spine demonstrates non-linear response under dynamic and time dependent load conditions [23, 25–27], the impact test performed in this study employed only small oscillations at each preload allowing us to consider a linearized model of the frequency-load (F-L) relationships. This methodology, previously used by several authors to characterize the mechanics of impact on the hip [81], the thoraco-lumbar [43, 58] and lumbosacral spine, in effect provides the slope of the F-L curve at each preload.…”

Section: Discussionmentioning

confidence: 99%

The degenerative state of the intervertebral disk independently predicts the failure of human lumbar spine to high rate loading: An experimental study

Alkalay

Vader

Hackney

2015

Clinical Biomechanics

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Background In the elderly, 30–50% of patients report a fall event to precede the onset of vertebral fractures. The dynamic characteristics of the spine determine the peak forces on the vertebrae in a fall. However, we know little about the effect of intervertebral disk degeneration on the failure of human spines under the high loading rates associated with such falls. We hypothesized that MR estimates of disk hydration and viscoelastic properties will provide better estimates of failure strength than bone density alone. Methods Seventeen L1–L3 human spine segments were imaged (Magnetic Resonance imaging, Dual-energy X-ray absorptiometry), their dynamic responses quantified using pendulum based impact, and the spines tested to failure under high rate loading simulating a fall event. The spines’ stiffness and damping constants were computed (Kelvin–Voigt model) with disk hydration and geometry assessed from T2 and proton density images. Findings Under impact, the spines exhibited a second-order underdamped response with stiffness and damping ranging (17.9–754.5)kN/m and (133.6–905.3)Ns/m respectively. Damping, but not stiffness, was negatively correlated with higher ultimate strength (p<0.05). Higher bone mineral density and MR-estimated disk hydration correlated with higher ultimate strength (p<0.01 for both). No such correlations were observed for the T2 values. Adding disk hydration yielded a 20% increase in the model’s association with failure load compared to bone density alone (MANOVA, p<0.001). Interpretation The strong correlation between disk viscoelastic properties and MR-estimated hydration with the spine segments ultimate strength clearly demonstrate the need to include disk degeneration as part of fracture risk assessment in the elderly spine.

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Analysis of compressive creep behavior of the vertebral unit subjected to a uniform axial loading using exact parametric solution equations of Kelvin-solid models—Part II. Rhesus monkey intervertebral joints

Cited by 18 publications

References 3 publications

Intervertebral Disc Response to Cyclic Loading—An Animal Model

Intervertebral Disc Response to Cyclic Loading—An Animal Model

The biomechanics of vibration and low back pain

The degenerative state of the intervertebral disk independently predicts the failure of human lumbar spine to high rate loading: An experimental study

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