Synchrotron tomography of intervertebral disc deformation quantified by digital volume correlation reveals microstructural influence on strain patterns
File(s)
Published version
OA Location
Author(s)
Type
Journal Article
Abstract
The intervertebral disc (IVD) has a complex and multiscale extracellular matrix structure which provides unique mechanical properties to withstand physiological loading. Low back pain has been linked to degeneration of the disc but reparative treatments are not currently available. Characterising the disc’s 3D microstructure and its response in a physiologically relevant loading environment is required to improve understanding of degeneration and to develop new reparative treatments. In this study, techniques for imaging the native IVD, measuring internal deformation and mapping volumetric strain were applied to an in situ compressed ex vivo rat lumbar spine segment. Synchrotron X-ray micro-tomography (synchrotron CT) was used to resolve IVD structures at microscale resolution. These image data enabled 3D quantification of collagen bundle orientation and measurement of local displacement in the annulus fibrosus between sequential scans using digital volume correlation (DVC). The volumetric strain mapped from synchrotron CT provided a detailed insight into the micromechanics of native IVD tissue. The DVC findings showed that there was no slipping at lamella boundaries, and local strain patterns were of a similar distribution to the previously reported elastic network with some heterogeneous areas and maximum strain direction aligned with bundle orientation, suggesting bundle stretching and sliding. This method has the potential to bridge the gap between measures of macro-mechanical properties and the local 3D micro-mechanical environment experienced by cells. This is the first evaluation of strain at the micro scale level in the intact IVD and provides a quantitative framework for future IVD degeneration mechanics studies and testing of tissue engineered IVD replacements.
Date Issued
2019-07-01
Date Acceptance
2019-05-07
Citation
Acta Biomaterialia, 2019, 92, pp.290-304
ISSN
1742-7061
Publisher
Elsevier
Start Page
290
End Page
304
Journal / Book Title
Acta Biomaterialia
Volume
92
Copyright Statement
© 2019 Acta Materialia Inc. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000473380800024&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Technology
Engineering, Biomedical
Materials Science, Biomaterials
Engineering
Materials Science
Intervertebral disc
X-ray micro-tomography
Strain
Digital volume correlation
INTER-LAMELLAR MATRIX
ANNULUS-FIBROSUS
NUCLEUS PULPOSUS
MECHANICAL-PROPERTIES
ELECTRON TOMOGRAMS
RESIDUAL STRAINS
ANULUS FIBROSUS
PHASE
COMPRESSION
BEHAVIOR
Publication Status
Published
Date Publish Online
2019-05-11