Transient swelling behavior of the bovine caudal disc

Bezci, Semih E.; Torres, Kyelo; Carraro, Carlo; Chiavacci, Dominic; Werbner, Benjamin; Lim, Shiyin; O’Connell, Grace D.

doi:10.1016/j.jmbbm.2020.104089

Cited by 8 publications

(5 citation statements)

References 37 publications

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“…Despite improvements in availability, accessibility, consistency, and ease of manipulation, experimental limitations still prevent assessment of intradiscal deformations and stress distributions between disc components with injuries or degeneration. Instead, in vitro studies primarily assess joint-level bulk mechanics, compositional changes, or biological response ( Oshima et al, 1993 ; Korecki et al, 2008a , b ; Roberts et al, 2008 ; Walter et al, 2011 ; Michalek and Iatridis, 2012 ; Bezci et al, 2015 , 2020a , b ; Bezci and O’Connell, 2018 ). The growing wealth of data that can be obtained from the bovine caudal discs makes it an ideal animal model to develop a validated and comprehensive computational tool to assess in situ mechanics.…”

Section: Introductionmentioning

confidence: 99%

A Robust Multiscale and Multiphasic Structure-Based Modeling Framework for the Intervertebral Disc

Zhou

Lim

O’Connell

2021

Front. Bioeng. Biotechnol.

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A comprehensive understanding of multiscale and multiphasic intervertebral disc mechanics is crucial for designing advanced tissue engineered structures aiming to recapitulate native tissue behavior. The bovine caudal disc is a commonly used human disc analog due to its availability, large disc height and area, and similarities in biochemical and mechanical properties to the human disc. Because of challenges in directly measuring subtissue-level mechanics, such as in situ fiber mechanics, finite element models have been widely employed in spinal biomechanics research. However, many previous models use homogenization theory and describe each model element as a homogenized combination of fibers and the extrafibrillar matrix while ignoring the role of water content or osmotic behavior. Thus, these models are limited in their ability in investigating subtissue-level mechanics and stress-bearing mechanisms through fluid pressure. The objective of this study was to develop and validate a structure-based bovine caudal disc model, and to evaluate multiscale and multiphasic intervertebral disc mechanics under different loading conditions and with degeneration. The structure-based model was developed based on native disc structure, where fibers and matrix in the annulus fibrosus were described as distinct materials occupying separate volumes. Model parameters were directly obtained from experimental studies without calibration. Under the multiscale validation framework, the model was validated across the joint-, tissue-, and subtissue-levels. Our model accurately predicted multiscale disc responses for 15 of 16 cases, emphasizing the accuracy of the model, as well as the effectiveness and robustness of the multiscale structure-based modeling-validation framework. The model also demonstrated the rim as a weak link for disc failure, highlighting the importance of keeping the cartilage endplate intact when evaluating disc failure mechanisms in vitro. Importantly, results from this study elucidated important fluid-based load-bearing mechanisms and fiber-matrix interactions that are important for understanding disease progression and regeneration in intervertebral discs. In conclusion, the methods presented in this study can be used in conjunction with experimental work to simultaneously investigate disc joint-, tissue-, and subtissue-level mechanics with degeneration, disease, and injury.

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Section: Introductionmentioning

confidence: 99%

A Robust Multiscale and Multiphasic Structure-Based Modeling Framework for the Intervertebral Disc

Zhou

Lim

O’Connell

2021

Front. Bioeng. Biotechnol.

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“…In degenerated discs, hydrostatic pressure is reduced due to a loss of glycosaminoglycans in the nucleus and inner annulus and applied compressive forces are transmitted directly to the endplates, which affects the response of the motion segment to axial loading 16,17 . In this way, the amount of glycosaminoglycans in the disc affects stress and strain distribution and motion segment mechanical behavior 18‐20 …”

Section: Resultsmentioning

confidence: 99%

“…16,17 In this way, the amount of glycosaminoglycans in the disc affects stress and strain distribution and motion segment mechanical behavior. [18][19][20] Concentric and radial tears and rim lesions are common in degenerated discs, [21][22][23] and there is a correlation between loss of disc height and annular fissures in degenerative discs. 7 These changes in disc structure result in a decrease in torsional stiffness and an increase in flexion and extension stiffness when lesions are present.…”

Section: Sample Selection: Extent Of Degenerationmentioning

confidence: 99%

Spine biomechanical testing methodologies: The controversy of consensus vs scientific evidence

2021

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Biomechanical testing methodologies for the spine have developed over the past 50 years. During that time, there have been several paradigm shifts with respect to techniques. These techniques evolved by incorporating state-of-the-art engineering principles, in vivo measurements, anatomical structure-function relationships, and the scientific method. Multiple parametric studies have focused on the effects that the experimental technique has on outcomes. As a result, testing methodologies have evolved, but there are no standard testing protocols, which makes the comparison of findings between experiments difficult and conclusions about in vivo performance challenging. In 2019, the international spine research community was surveyed to determine the consensus on spine biomechanical testing and if the consensus opinion was consistent with the scientific evidence. More than 80 responses to the survey were received. The findings of this survey confirmed that while some methods have been commonly adopted, not all are consistent with the scientific evidence. This review summarizes the scientific literature, the current consensus, and the authors' recommendations on best practices based on the compendium of available evidence.

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“…Similarly, Brinckmann and Horst 36 examined the effect of vertebral body fracture, intradiscal injection, and partial discectomy on disc height and radial bulge, reporting height change of the total motion segment but avoiding the absolute disc height. More recently, our lab reported changes in disc height during creep‐recovery testing of bovine discs, where disc height change was assumed as the change in displacement of the mechanical testing device 37 . Around the same time, Feki et al 38 asserted that disc recovery is governed by osmotic conditions, reporting changes in normalized load and relaxation time without specifying disc geometry or normalization method.…”

Section: Review: Methods For Measuring Disc Geometrymentioning

confidence: 99%

“…More recently, our lab reported changes in disc height during creep‐recovery testing of bovine discs, where disc height change was assumed as the change in displacement of the mechanical testing device. 37 Around the same time, Feki et al 38 asserted that disc recovery is governed by osmotic conditions, reporting changes in normalized load and relaxation time without specifying disc geometry or normalization method. Ultimately, studies reporting disc mechanics have continued to be published without normalizing to specimen geometry, making it difficult to compare results.…”

Section: Review: Methods For Measuring Disc Geometrymentioning

confidence: 99%

Disc geometry measurement methods affect reported compressive mechanics by up to 65%

et al. 2022

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Mechanical testing is a valuable tool for assessing intervertebral disc health, but the wide range of testing protocols makes it difficult to compare results from different studies. Normalizing mechanical properties by disc geometry allows for such comparisons, but there is little consistency in the methods by which disc geometry is measured. As such, we hypothesized that methods used to measure disc geometry would impact reported mechanical properties. Disc height and area were measured using computed tomography (CT), digital calipers, and ImageJ to yield three different measurements for disc height and six for disc area. Disc heights measured by digital calipers ex situ were >30% less than disc heights measured in situ by CT, and disc areas measured ex situ using ImageJ were >30% larger than those measured by CT. This significantly affected reported mechanical properties, leading to a 65% reduction in normalized compressive stiffness in the most extreme case. Though we cannot quantitatively correct between methods, results presented in this study suggest that disc geometry measurement methods have a significant impact on normalized mechanical properties and should be accounted for when comparing results.

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Transient swelling behavior of the bovine caudal disc

Cited by 8 publications

References 37 publications

A Robust Multiscale and Multiphasic Structure-Based Modeling Framework for the Intervertebral Disc

A Robust Multiscale and Multiphasic Structure-Based Modeling Framework for the Intervertebral Disc

Spine biomechanical testing methodologies: The controversy of consensus vs scientific evidence

Disc geometry measurement methods affect reported compressive mechanics by up to 65%

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