Significance of cartilage endplate within herniated disc tissue

Lama, Polly; Zehra, Uruj; Balkovec, Christian; Claireaux, Henry; Flower, Luke; Harding, Ian; Dolan, Patricia; Adams, Michael A.

doi:10.1007/s00586-014-3399-3

Cited by 95 publications

(112 citation statements)

References 41 publications

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“…Ultimately, even with fiber-reinforcement, CEP shear strains are large due to significant lateral expansion of the NP. This suggests that excessive shear deformation may be a failure mechanism of the CEP, consistent with clinical observations of CEP delamination (Kokubun et al, 1996; Lama et al, 2014). Moreover, while fiber-reinforcement can affect CEP mechanics, it doesn’t significantly affect disc-level mechanics, with reinforcement increasing maximum disc reaction force by only 13% without affecting equilibrium reaction force.…”

Section: Discussionsupporting

confidence: 86%

Human cartilage endplate permeability varies with degeneration and intervertebral disc site

DeLucca

Cortés

Jacobs

et al. 2016

Journal of Biomechanics

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Despite the critical functions the human cartilage endplate (CEP) plays in the intervertebral disc, little is known about its structural and mechanical properties and their changes with degeneration. Quantifying these changes with degeneration is important for understanding how the CEP contributes to the function and pathology of the disc. Therefore the objectives of this study were to quantify the effect of disc degeneration on human CEP mechanical properties, determine the influence of superior and inferior disc site on mechanics and composition, and simulate the role of collagen fibers in CEP and disc mechanics using a validated finite element model. Confined compression data and biochemical composition data were used in a biphasic-swelling model to calculate compressive extrafibrillar elastic and permeability properties. Tensile properties were obtained by applying published tensile test data to an ellipsoidal fiber distribution. Results showed that with degeneration CEP permeability decreased 50–60% suggesting that transport is inhibited in the degenerate disc. CEP fibers are organized parallel to the vertebrae and nucleus pulposus and may contribute to large shear strains (0.1–0.2) and delamination failure of the CEP commonly seen in herniated disc tissue. Fiber-reinforcement also reduces CEP axial strains thereby enhancing fluid flux by a factor of 1.8. Collectively, these results suggest that the structure and mechanics of the CEP may play critical roles in the solute transport and disc mechanics.

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Section: Discussionsupporting

confidence: 86%

Human cartilage endplate permeability varies with degeneration and intervertebral disc site

DeLucca

Cortés

Jacobs

et al. 2016

Journal of Biomechanics

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“…Our preliminary findings suggest that lack of integration, especially at the CEP-VEP interface, is associated with IVD degeneration and adds to the current knowledge within the field, whereby lack of structural integrity at the CEP-VEP junction is increasingly being implicated in the aetiology of herniations [31], [20], [40], [16], [3]. Possible reasons for reduced connectivity at the CEP-VEP junction may be either an increase in marrow spaces abutting this interface [18], so reducing locations where fibre integration is possible or retention of discontinuities in the endplate following insufficient retraction of the notochord during spinal development [8].…”

Section: Discussionmentioning

confidence: 87%

“…The degenerative changes seen in the CEP have been well characterised and shown to be associated with IVD degeneration [2]; they will inevitably impinge on the state of connectivity at the disc and vertebra interfaces. Lama et al [16] have highlighted that any loss in CEP will result in increased endplate permeability thus possibly facilitating endplate inflammation or even disc infection which may subsequently play a role in the generation of Modic changes as observed on MRI.…”

Section: Discussionmentioning

confidence: 99%

Staying connected: structural integration at the intervertebral disc–vertebra interface of human lumbar spines

et al. 2016

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Purpose:To investigate the microscopic fibrous integration between the intervertebral disc, cartilage endplates and vertebral endplates in human lumbar spines of varying degrees of degeneration using differential interference contrast (DIC) optics. Weakness at these junctions is considered to be an important factor in the aetiology of disc herniations. Methods:Magnetic resonance images (MRIs) of cadaveric lumbar spines were graded for degeneration and motion segments from a range of degenerative grades isolated and bisected sagittally. Following fixation and decalcification, these were cut into segments containing anterior or posterior annulus fibrosus or nucleus pulposus. The segments were cryo-sectioned and sections visualised using both standard light and DIC microscopy. Results:Detachment at the interface between the disc and vertebrae increased with greater degenerative grade (from 1.9% in Grade I to 28% in Grade V), especially at the boundary between the cartilage and vertebral endplates. DIC microscopy revealed the fibrous organisation at the IVD-cartilage endplate interface with structural features, such as annular lamellae branching and nodal insertions in the nucleus pulposus region; these have been previously observed in ovine spines, but were less uniform in humans.Structural integrity of the IVD and cartilage endplate was also lost with increasing degeneration. Conclusions:This preliminary study shows that microscopic structural features may act to maintain attachment between the IVD and CEP in the human spine. Loss of structural integrity in this region may destabilise the spine, possibly altering the mechanical environment of the cells in the disc and so potentially contribute to the aetiopathogenesis of IVD degeneration.

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“…Injury at this site has received growing interest due to its clinical significance. For instance, avulsion of the cartilage endplate (CEP) from bone at the cartilage-vertebral endplate junction (EPJ) may be the most common form of disc injury since it is reportedly the initial site of failure in over 60% of intervertebral disc herniations 1,2 (Fig. 1B).…”

Section: Introductionmentioning

confidence: 99%

Structure‐function relationships at the human spinal disc‐vertebra interface

Berg-Johansen

Fields

Liebenberg

et al. 2017

Journal Orthopaedic Research

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Damage at the intervertebral disc‐vertebra interface associates with back pain and disc herniation. However, the structural and biomechanical properties of the disc‐vertebra interface remain underexplored. We sought to measure mechanical properties and failure mechanisms, quantify architectural features, and assess structure‐function relationships at this vulnerable location. Vertebra‐disc‐vertebra specimens from human cadaver thoracic spines were scanned with micro‐computed tomography (μCT), surface speckle‐coated, and loaded to failure in uniaxial tension. Digital image correlation (DIC) was used to calculate local surface strains. Failure surfaces were scanned using scanning electron microscopy (SEM), and adjacent sagittal slices were analyzed with histology and SEM. Seventy‐one percent of specimens failed initially at the cartilage endplate‐bone interface of the inner annulus region. Histology and SEM both indicated a lack of structural integration between the cartilage endplate (CEP) and bone. The interface failure strength was increased in samples with higher trabecular bone volume fraction in the vertebral endplates. Furthermore, failure strength decreased with degeneration, and in discs with thicker CEPs. Our findings indicate that poor structural connectivity between the CEP and vertebra may explain the structural weakness at this region, and provide insight into structural features that may contribute to risk for disc‐vertebra interface injury. The disc‐vertebra interface is the site of failure in the majority of herniation injuries. Here we show new structure‐function relationships at this interface that may motivate the development of diagnostics, prevention strategies, and treatments to improve the prognosis for many low back pain patients with disc‐vertebra interface injuries. © 2017 The Authors. Journal of Orthopaedic Research® Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 36:192–201, 2018.

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Significance of cartilage endplate within herniated disc tissue

Cited by 95 publications

References 41 publications

Human cartilage endplate permeability varies with degeneration and intervertebral disc site

Human cartilage endplate permeability varies with degeneration and intervertebral disc site

Staying connected: structural integration at the intervertebral disc–vertebra interface of human lumbar spines

Structure‐function relationships at the human spinal disc‐vertebra interface

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