'Stress' distributions inside intervertebral discs

Adams, Michael A.; McNally, Donal; Dolan, Patricia

doi:10.1302/0301-620x78b6.1287

Cited by 517 publications

(308 citation statements)

References 32 publications

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“…In vitro disc pressure response to applied axial loading in the human motion segments was in agreement with previous human studies [24;51;52]. Decreased disc pressure for degenerated discs, as found in the present study, has been noted previously [53][54][55][56][57][58][59].…”

Section: Discussionsupporting

confidence: 93%

Mature runt cow lumbar intradiscal pressures and motion segment biomechanics

2009

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Background Context-The optimal animal model for in vivo testing of spinal implants, particularly total or partial disc replacement devices, has not yet been determined. Mechanical and morphological similarities of calf and human spines have been reported; however, limitations of the calf model include open growth plates and oversized vertebrae with growth. Mature runt cows (Corrientes breed) may avoid these limitations.

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Section: Discussionsupporting

confidence: 93%

Mature runt cow lumbar intradiscal pressures and motion segment biomechanics

2009

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“…During the whole ageing sequela, a progressive loss of the water fraction in the whole disc (due to the reduction of the proteoglycan content and, therefore, of the osmotic gradient) and a corresponding increase in the fibrotic tissue are generally observed [3,4]. Within the nucleus pulposus, the water content was found to decrease from 5.8 gH 2 O/g dry weight at an age of 14 years (85 % volume fraction) to 3.3 gH 2 O/g dry weight at age 91 years (75 %) [66].…”

Section: Cellular and Matrix Changesmentioning

confidence: 99%

Ageing and degenerative changes of the intervertebral disc and their impact on spinal flexibility

et al. 2014

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Purpose Degeneration of the intervertebral disc is associated with various morphological changes of the disc itself and of the adjacent structures, such as reduction of the water content, collapse of the intervertebral space, disruption and tears, and osteophytes. These morphological changes of the disc are linked to alterations of the spine flexibility. This paper aims to review the literature about the ageing and degenerative changes of the intervertebral disc and their link with alterations in spinal biomechanics, with emphasis on flexibility. Methods Narrative literature review. Results Clinical instability of the motion segment, usually related to increased flexibility and hypothesized to be connected to early, mild disc degeneration and believed to be responsible for low back pain, was tested in numerous in vitro studies. Despite some disagreement in the findings, a trend toward spinal stiffening with the increasing degeneration was observed in most studies. Tests about tears and fissures showed inconsistent results, as well as for disc collapse and dehydration. Vertebral osteophytes were found to be effective in stabilizing the spine in bending motions. Conclusions The literature suggests that the degenerative changes of the intervertebral disc and surrounding structures lead to subtle alteration of the mechanical properties of the functional spinal unit. A trend toward spinal stiffening with the increasing degeneration has been observed in most studies.

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“…A recently published review of the literature clearly pointed out that in animal models at least disc degeneration can be provoked by inappropriate mechanical signals [16,19]. Multiple mechanical factors affect the IVD in vivo [1,14], as this structure has to provide flexibility, stabilization and shock absorbance in its function as the joint of the spine. Although, mechanical loading appears to influence tissue turnover, there is currently little information on how the load intensities affect cellular responses.…”

Section: Introductionmentioning

confidence: 99%

“…Cells were harvested 24 h after the end of stimulation and changes in the expression of genes known to influence IVD matrix turnover (collagen-I, collagen-II, aggrecan, MMP1, MMP2, MMP3, MMP13) were analyzed by real-time RT-PCR. A Wilcoxon signed-rank test 1 and a Wilcoxon 2-sample test 2 were performed to detect differences between the stimulated and control samples 1 and differences between low and high hydrostatic pressure 2 . Multiple testing was considered by adjusting the p value appropriately.…”

mentioning

confidence: 99%

Regulation of gene expression in intervertebral disc cells by low and high hydrostatic pressure

et al. 2006

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Intervertebral disc structures are exposed to wide ranges of intradiscal hydrostatic pressure during different loading excercises and are at their minimum during lying or relaxed sitting and at maximum during lifting weights with a round back. We hypothesize that these different loading magnitudes influence the intervertebral disc (IVD) by alteration of disc matrix turnover depending on their magnitudes. Therefore the aim of this study was to assess changes in gene expression of human nucleus cells after the application of low hydrostatic pressure (0.25 MPa) and high hydrostatic pressure (2.5 MPa). IVD cells isolated from the nucleus of human (n = 18) and bovine (n = 24 from four animals) disc biopsies were seeded into three-dimensional collagen type-I matrices and exposed to the different loading magnitudes by specially developed pressure chambers. The lower pressure range (0.25 MPa, 30 min, 0.1 Hz) was applied with a recently published device by using an external compression cylinder. For the application of higher loads (2.5 MPa, 30 min, 0.1 Hz) the cell-loaded collagen gels were sealed into sterile bags with culture medium and stimulated in a newly developed water-filled compression cylinder by using a loading frame. These methods allowed the comparison of loading regimes in a wide physiological range under an equal three-dimensional culture conditions. Cells were harvested 24 h after the end of stimulation and changes in the expression of genes known to influence IVD matrix turnover (collagen-I, collagen-II, aggrecan, MMP1, MMP2, MMP3, MMP13) were analyzed by real-time RT-PCR. A Wilcoxon signed-rank test 1 and a Wilcoxon 2-sample test 2 were performed to detect differences between the stimulated and control samples 1 and differences between low and high hydrostatic pressure 2 . Multiple testing was considered by adjusting the p value appropriately. Both regimes of hydrostatic pressure influenced gene expression in nucleus cells with opposite tendencies for the matrix forming proteins aggrecan and collagen type-I in response to the two different pressure magnitudes: Low hydrostatic-pressure (0.25 MPa) tended to increase collagen-I and aggrecan expression of human nucleus cells (P < 0.05) but only to a small degree. High hydrostatic pressure (2.5 MPa) tended to decrease gene expression of all anabolic proteins with significant effects on aggrecan expression of nucleus cells (P = 0.004). Low hydrostatic pressure had no influence on the expression of matrix metalloproteinases (MMP1, MMP2, MMP3 and MMP13). In contrast, high hydrostatic pressure tended to increase the expression of MMP1, MMP3 and MMP13 of human nucleus cells with high individualindividual variations. The decreased expression of aggrecan (P = 0.008) and collagen type II (P = 0.023) and the increased MMP3 expression (P = 0.008) in response to high hydrostatic pressure could be confirmed in additional experiments with bovine nucleus cells. These results suggest that hydrostatic pressure as one of the physiological stimuli of the IVD may inf...

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'Stress' distributions inside intervertebral discs

Cited by 517 publications

References 32 publications

Mature runt cow lumbar intradiscal pressures and motion segment biomechanics

Mature runt cow lumbar intradiscal pressures and motion segment biomechanics

Ageing and degenerative changes of the intervertebral disc and their impact on spinal flexibility

Regulation of gene expression in intervertebral disc cells by low and high hydrostatic pressure

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