Effects of Swelling Pressure and Hydraulic Permeability on Dynamic Compressive Behavior of Lumbar Annulus Fibrosus

Yao, Hai; Justiz, Marc Antoine; Flagler, Daniel J.; Gu, Wei Yong

doi:10.1114/1.1523920

Cited by 68 publications

(70 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[2][3][4][17][18][19] Nanomechanical measurements of aggrecan interactions also demonstrate the relevance of electrostatic interactions, as described by PoissonBoltzmann-based models, in defining how aggrecan molecules contribute to compressive stiffness. 20 The fixed charge density may be related to GAG concentration using the molecular weight and charge of a chondroitin sulfate disaccharide by: fixed charge density ϭ [GAG] ϫ 2/502.5 ϫ 10 3 .…”

Section: Discussionmentioning

confidence: 99%

“…[1][2][3][4] A loss of proteoglycans in the central nucleus pulposus region is a clear sign of early degeneration. 5,6 The tissue mechanical properties depend on proteoglycan content; therefore, this compositional information is required for mechanical modeling of the disc 1,[7][8][9][10] and offers promise for improved understanding of disc function and remodeling in healthy and diseased states.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Measurements of Proteoglycan and Water Content Distribution in Human Lumbar Intervertebral Discs

Iatridis¹,

MacLean²,

O’Brien³

et al. 2007

Spine

144

140

View full text Add to dashboard Cite

Study Design. Study of regional variations in composition in a sample of 9 mildly to moderately degenerated human intervertebral discs.Objective. The aim of this study was to obtain proteoglycan distribution in human lumbar discs with high position resolution in the: 1) sagittal, 2) coronal, and 3) axial directions.Summary of Background Data. Regional variation in disc proteoglycan content has only been reported in coronal sections in a small number of discs and with low spatial resolution in the sagittal direction, and has not been reported in the axial direction.Methods. Each of 9 human L2-L3 or L3-L4 lumbar discs (age, 53-56 years) were dissected into 36 to 41 specimens using a rectangular cutting die, measured for water content and analyzed for glycosaminoglycan content using the dimethylmethylene blue dye binding assay.Results. The intervertebral discs were mildly to moderately degenerated. They had glycosaminoglycan content ranging ϳ40 to 600 g/mg dry tissue, with largest values in the nucleus and lowest in the outer anulus. In general, posterior regions had greater glycosaminoglycan content than anterior regions, although values were not as high as in the nucleus. Small variations in glycosaminoglycan content in the axial direction were observed with the largest values in the center, although this variation was small compared with radial variations. Water content results followed similar trends as glycosaminoglycan content with average values ranging from ϳ66% to 86%.Conclusions. A refined map of proteoglycan content is presented with 3 important findings. First, sagittal variations were distinct from coronal variations. Second, the proteoglycan content was not uniform across the nucleus regions. Third, some specimens had localized variations in proteoglycan and water contents suggestive of focal damage and degeneration.Key words: proteoglycans, aggrecan, glycosaminoglycan content, fixed charge density, intervertebral disc, degeneration. Spine 2007;32: [1493][1494][1495][1496][1497] The distribution of proteoglycan content in the intervertebral disc is functionally important in defining the swelling behaviors, streaming potential, and compressive properties of the tissue.1-4 A loss of proteoglycans in the central nucleus pulposus region is a clear sign of early degeneration. 5,6 The tissue mechanical properties depend on proteoglycan content; therefore, this compositional information is required for mechanical modeling of the disc 1,7-10 and offers promise for improved understanding of disc function and remodeling in healthy and diseased states.Previous reports of proteoglycan content distribution in the disc have provided relatively coarse information on the distribution in the sagittal (front to back) direction on a large number of specimens using sulfated glycosaminoglycan (GAG) measurements 6 or with a higher spatial distribution from a relatively small number of discs using radioactive ion tracers to obtain direct measurements of fixed charge density. 11 The proteoglycan distributions in the coronal ...

show abstract

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Measurements of Proteoglycan and Water Content Distribution in Human Lumbar Intervertebral Discs

Iatridis¹,

MacLean²,

O’Brien³

et al. 2007

Spine

144

140

View full text Add to dashboard Cite

show abstract

“…Finally, this study provides in vitro mechanical and water content data that may be used for comparison with the growing numbers of in vivo and organ culture studies using rat lumbar and caudal models. 6,7,10,12,13,[15][16][17]19,27,29 A quantitative association of relative contributions of disc bulging and volume loss would require a 3-dimensional multiphasic finite element model with intrinsic solid phase viscoelasticity, which is beyond the scope of this manuscript, although some similar models on human lumbar disc exist. 34…”

Section: Discussionmentioning

confidence: 99%

“…11-14 Loading conditions on the motion segment affect the degree of hydration of the intervertebral disc and, in particular of the nucleus pulposus, under loading, and alterations in hydration subsequently also affect the elastic and viscoelastic mechanical behaviors of the intervertebral disc. 1,7,[15][16][17] There is a limited understanding of the time-dependent association between water loss and viscoelastic creep in the disc, and this requires additional experiments in a controlled in vitro environment that permits inferences regarding volume loss and mechanisms of viscoelasticity. There are very few studies on effects of cyclic loading on fundamental motion segment creep and hydration and improved understanding of the motion segment behaviors under cyclic or repetitive loading conditions is a priority for defining safe loading regimens.…”

mentioning

confidence: 99%

Different Effects of Static Versus Cyclic Compressive Loading on Rat Intervertebral Disc Height and Water Loss In Vitro

Masuoka¹,

Michalek²,

MacLean³

et al. 2007

Spine

View full text Add to dashboard Cite

Study Design-In vitro biomechanical study on rat caudal motion segments to evaluate association between compressive loading and water content under static and cyclic conditions.Objective-To test hypotheses: 1) there is no difference in height loss and fluid (volume) loss of discs loaded in compression under cyclic (0.15-1.0 MPa) and static conditions with the same rootmean-square (RMS) magnitudes (0.575 MPa); and 2) after initial disc bulge, tissue water loss is directly proportional to height loss under static loading. Summary of Background Data-Disc degeneration affects water content, elastic and viscoelastic behaviors. There is limited understanding of the association between transient water loss and viscoelastic creep in a controlled in vitro environment where inferences may be made regarding mechanisms of viscoelasticity.Methods-A total of 126 caudal motion segments from 21 Wistar rats were tested in compression using 1 of 6 protocols: Static loading at 1.0 MPa for 9, 90, and 900 minutes, Cyclic loading at 0.15 to 1.0 MPa/1 Hz for 90 minutes, Mid-Static loading at 0.575 MPa for 90 minutes, and control. Water content was then measured in anulus and nucleus regions.Results-Percent water loss was significantly greater in nucleus than anulus regions, suggesting some water redistribution, with average values under 1 MPa static loading of 23.0% and 14.9% after 90 minutes and 26.9% and 17.6% after 900 minutes, respectively. Cyclic loading resulted in significantly greater height loss (0.506 ± 0.108 mm) than static loading with the same RMS value (0.402 ± 0.096 mm), but not significantly less than static loading at peak value (0.539 ± 0.122 mm). Significant and strong correlations were found between percent water loss and disc height loss, suggesting water was lost through volume decrease.Conclusion-Peak magnitude of cyclic compression and not RMS value was most important in determining height change and water loss, likely due to differences between disc creep and recovery rates. Water redistribution from nucleus to anulus occurred under loading consistent with an initial elastic compression (and associated disc bulge) followed by a reduction in disc volume over time.Address correspondence and reprint requests to James C. Iatridis, PhD, University of Vermont, 201 Perkins Building, 33 Colchester Ave, Burlington, VT 05405; E-mail: E-mail: james.iatridis@uvm.edu. The manuscript submitted does not contain information about medical device(s)/drug(s).No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript. NIH Public AccessAuthor Manuscript Spine (Phila Pa 1976 The intervertebral disc plays the essential biomechanical roles of supporting load and permitting motion in the spine. 1 The disc is a heterogeneous structure composed of a central nucleus pulposus surrounded by a highly organized fiber-reinforced anulus fibrosus. The nucleus pulposus is a hydrated gelatinous tissue composed of negatively charged glycosaminoglycans, coll...

show abstract

“…The IVD is primarily subjected to compressive load in vivo and has a strong propensity for swelling Urban and McMullin, 1988;Yao et al, 2002). The osmotic pressure of the IVD is mainly due to the high density of charged carboxyl and sulfate groups on the glycosaminoglycans of the proteoglycans within the tissue (Urban and Maroudas, 1980;Urban et al, 1979).…”

Section: Introductionmentioning

confidence: 99%

Effects of mechanical compression on metabolism and distribution of oxygen and lactate in intervertebral disc

Huang¹,

Gu²

2008

Journal of Biomechanics

Self Cite

125

View full text Add to dashboard Cite

The objective of this study was to examine the effects of mechanical compression on metabolism and distributions of oxygen and lactate in the intervertebral disc (IVD) using a new formulation of the triphasic theory. In this study, the cellular metabolic rates of oxygen and lactate were incorporated into the newly developed formulation of the mechano-electrochemical mixture model [Huang and Gu, J. Biomech. Eng., 129:423-429, 2007]. The model was used to numerically analyze metabolism and transport of oxygen and lactate in the IVD under static or dynamic compression. The theoretical analyses demonstrated that compressive loading could affect transport and metabolism of nutrients. Dynamic compression increased oxygen concentration, reduced lactate accumulation, and promoted oxygen consumption and lactate production (i.e., energy conversion) within the IVD. Such effects of dynamic loading were dependent on strain level and loading frequency, and more pronounced in the IVD with less permeable endplate. In contrast, static compression exhibited inverse effects on transport and metabolism of oxygen and lactate. The theoretical predictions in this study are in good agreement with those in the literature. This study established a new theoretical model for analyzing cellular metabolism of nutrients in hydrated, fibrous soft tissues under mechanical compression.

show abstract

Effects of Swelling Pressure and Hydraulic Permeability on Dynamic Compressive Behavior of Lumbar Annulus Fibrosus

Cited by 68 publications

References 43 publications

Measurements of Proteoglycan and Water Content Distribution in Human Lumbar Intervertebral Discs

Measurements of Proteoglycan and Water Content Distribution in Human Lumbar Intervertebral Discs

Different Effects of Static Versus Cyclic Compressive Loading on Rat Intervertebral Disc Height and Water Loss In Vitro

Effects of mechanical compression on metabolism and distribution of oxygen and lactate in intervertebral disc

Contact Info

Product

Resources

About