The Mechanical Role of the Radial Fiber Network Within the Annulus Fibrosus of the Lumbar Intervertebral Disc: A Finite Elements Study

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Mirit Sharabi ◽  
Aviad Levi-Sasson ◽  
Roza Wolfson ◽  
Kelly R. Wade ◽  
Fabio Galbusera ◽  
...  
Keyword(s):  
Intervertebral Disc ◽  
Annulus Fibrosus ◽  
Local Stress ◽  
Element Model ◽  
Collagen Fibers ◽  
Lumbar Intervertebral Disc ◽  
Fiber Network ◽  
Radial Fiber ◽  
The Matrix

The annulus fibrosus (AF) of the intervertebral disc (IVD) consists of a set of concentric layers composed of a primary circumferential collagen fibers arranged in an alternating oblique orientation. Moreover, there exists an additional secondary set of radial translamellar collagen fibers which connects the concentric layers, creating an interconnected fiber network. The aim of this study was to investigate the mechanical role of the radial fiber network. Toward that goal, a three-dimensional (3D) finite element model of the L3–L4 spinal segment was generated and calibrated to axial compression and pure moment loading. The AF model explicitly recognizes the two heterogeneous networks of fibers. The presence of radial fibers demonstrated a pronounced effect on the local disc responses under lateral bending, flexion, and extension modes. In these modes, the radial fibers were in a tensile state in the disc region that subjected to compression. In addition, the circumferential fibers, on the opposite side of the IVD, were also under tension. The local stress in the matrix was decreased in up to 9% in the radial fibers presence. This implies an active fiber network acting collectively to reduce the stresses and strains in the AF lamellae. Moreover, a reduction of 26.6% in the matrix sideways expansion was seen in the presence of the radial fibers near the neutral bending axis of the disc. The proposed biomechanical model provided a new insight into the mechanical role of the radial collagen fibers in the AF structure. This model can assist in the design of future IVD substitutes.

The role of the nucleus pulposus in neutral zone human lumbar intervertebral disc mechanics

2008 ◽  
Vol 41 (10) ◽  
pp. 2104-2111 ◽  
Author(s):  
Marco Cannella ◽  
Amy Arthur ◽  
Shanee Allen ◽  
Michael Keane ◽  
Abhijeet Joshi ◽  
...  
Keyword(s):  
Intervertebral Disc ◽  
Nucleus Pulposus ◽  
Neutral Zone ◽  
Lumbar Intervertebral Disc

scholarly journals A novel finite element model of the ovine lumbar intervertebral disc with anisotropic hyperelastic material properties

PLoS ONE ◽  
2017 ◽  
Vol 12 (5) ◽  
pp. e0177088 ◽  
Author(s):  
Gloria Casaroli ◽  
Fabio Galbusera ◽  
René Jonas ◽  
Benedikt Schlager ◽  
Hans-Joachim Wilke ◽  
...  
Keyword(s):  
Finite Element ◽  
Intervertebral Disc ◽  
Finite Element Model ◽  
Material Properties ◽  
Element Model ◽  
Hyperelastic Material ◽  
Lumbar Intervertebral Disc

Hierarchical Structure of the Intervertebral Disc

1989 ◽  
Vol 174 ◽  
Author(s):  
J. J. Cassidy ◽  
A. Hiltner ◽  
E. Baer
Keyword(s):  
Stress Relaxation ◽  
Intervertebral Disc ◽  
Hierarchical Structure ◽  
Composite Structure ◽  
Annulus Fibrosus ◽  
Optical Microscope ◽  
Collagen Fibers ◽  
The Hierarchical Structure ◽  
Vertebral Bodies ◽  
Collagenous Tissues

AbstractThe intervertebral disc is a complex hierarchical structure composed of the annulus fibrosus and nucleus pulposus which are anchored to the vertebral bodies by cartilaginous endplates. The hierarchical structure of the collagenous components of the intervertebral disc is characterized using optical microscope techniques. In the lamellae of the annulus, collagen fibers exhibit a planar crimped morphology similar to that seen in other collagenous tissues. A model of the intervertebral disc has been developed that incorporates the structure of the collagen fibers on the macro- and microscopic scales.Mechanical testing in load-deflection, stress relaxation, and creep modes reveals the response at each level of organization to compression. These mechanical data are analyzed with models that reflect the hierarchical composite structure.

scholarly journals Contrast-enhanced microCT evaluation of degeneration following partial and full width injuries to mouse lumbar intervertebral disc

2022 ◽  
Author(s):  
Remy E Walk ◽  
Hong Joo Moon ◽  
Simon Y Tang ◽  
Munish C Gupta
Keyword(s):  
Intervertebral Disc ◽  
Nucleus Pulposus ◽  
Annulus Fibrosus ◽  
Partial Width ◽  
Full Width ◽  
Lumbar Intervertebral Disc ◽  
Study Objective ◽  
Post Surgery ◽  
Contrast Enhanced ◽  
Ivd Degeneration

Study Design: Preclinical animal study. Objective: Evaluation of the degenerative progression resulting from either a partial- or full- width injury to the mouse lumbar intervertebral disc (IVD) using contrast-enhanced micro-computed tomography and histological analyses. We utilized a lateral-retroperitoneal surgical approach to access the lumbar IVD, and the injuries to the IVD were induced by either incising one side of the annulus fibrosus or puncturing both sides of the annulus fibrosus. The full-width injury caused dramatic reduction in nucleus pulposus hydration and significant degeneration. A partial-width injury produces localized deterioration around the annulus fibrosus site that resulted in local tissue remodeling without gross degeneration to the IVD. Methods: Female C57BL/6J mice of 3-4 months age were used in this study. They were divided into three groups to undergo a partial-width, full-width, or sham injuries. The L5/L6 and L6/S1 lumbar IVDs were surgically exposed using a lateral-retroperitoneal approach. The L6/S1 IVDs were injured using either a surgical scalpel (partial-width) or a 33G needle (full-width), with the L5/L6 serving as an internal control. These animals were allowed to recover and then sacrificed at 2-, 4-, or 8- weeks post-surgery. The IVDs were assessed for degeneration using contrast-enhanced microCT (CEμCT) and histological analysis. Results: The high-resolution 3D evaluation of the IVD confirmed that the respective injuries localized within one side of the annulus fibrosus or spanned the full width of the IVD. The full-width injury caused deteriorations in the nucleus pulposus after 2 weeks that culminated in significant degeneration at 8 weeks, while the partial width injury caused localized disruptions that remained limited to the annulus fibrosus. Conclusion: The use of CEμCT revealed distinct IVD degeneration profiles resulting from partial- and full- width injuries. The partial width injury may serve as a better model for IVD degeneration resulting from localized annulus fibrosus injuries in humans.

Disc Biomechanical Response due to Incomplete Length of Collagen Fibers in Various Regions of Annulus Fibrosus: A Finite Element Investigation

2010 ◽  
Author(s):  
Mozammil Hussain ◽  
Ralph E. Gay ◽  
Kai-Nan An
Keyword(s):  
Annulus Fibrosus ◽  
Past Research ◽  
Collagen Fibers ◽  
Cervical Disc ◽  
Clear Understanding ◽  
Fiber Structure ◽  
Laminar Organization ◽  
Biomechanical Response ◽  
The Subject

Collagen fibers in the annulus fibrosus (AF) play a significant role in maintaining the disc mechanical behavior. In healthy discs, AF fibers are concentrically arranged in a zigzag fashion. Tensile loads are transmitted to these fibers when the disc is loaded in compression. As a result, disc bulging occurs. Initiation and progression of mild cervical disc degeneration (DD) has been the subject of clinical concern [1]. The mild DD is associated with structural interruption in laminar organization of fibers in partial AF regions and incomplete length of fibers is a major form of structural interruption in AF fibers [2]. Moreover, a loss of lamellar fiber structure contributes to the progression of spinal deformity [3]. Past research have documented the biomechanical role of complete length of fibers in governing a healthy disc behavior [4]; however, there is a lack of clear understanding as to how incomplete length of fibers in different AF regions affect overall disc biomechanics and how they may play a role in initiating the propagation of DD. The focus of the current study is to investigate the disc biomechanical response due to incomplete length of fibers in outer, middle, and inner AF regions.

scholarly journals A Review of Animal Models of Intervertebral Disc Degeneration: Pathophysiology, Regeneration, and Translation to the Clinic

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Chris Daly ◽  
Peter Ghosh ◽  
Graham Jenkin ◽  
David Oehme ◽  
Tony Goldschlager
Keyword(s):  
Back Pain ◽  
Animal Models ◽  
Intervertebral Disc ◽  
Disc Degeneration ◽  
Intervertebral Disc Degeneration ◽  
Discogenic Pain ◽  
Lumbar Intervertebral Disc ◽  
Large Size ◽  
Testing Potential

Lower back pain is the leading cause of disability worldwide. Discogenic pain secondary to intervertebral disc degeneration is a significant cause of low back pain. Disc degeneration is a complex multifactorial process. Animal models are essential to furthering understanding of the degenerative process and testing potential therapies. The adult human lumbar intervertebral disc is characterized by the loss of notochordal cells, relatively large size, essentially avascular nature, and exposure to biomechanical stresses influenced by bipedalism. Animal models are compared with regard to the above characteristics. Numerous methods of inducing disc degeneration are reported. Broadly these can be considered under the categories of spontaneous degeneration, mechanical and structural models. The purpose of such animal models is to further our understanding and, ultimately, improve treatment of disc degeneration. The role of animal models of disc degeneration in translational research leading to clinical trials of novel cellular therapies is explored.

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