Faculty Collaboration Database

Finite element analysis of the cervical spine: a material property sensitivity study. Clin Biomech (Bristol, Avon) 1999 Jan;14(1):41-53

Date

01/05/2000

Pubmed ID

10619089

DOI

10.1016/s0268-0033(98)00036-9

Scopus ID

2-s2.0-0032930440 (requires institutional sign-in at Scopus site)   161 Citations

Abstract

OBJECTIVE: The study determined the effect of variations in the material properties of the cervical spinal components on the output of the finite element analysis (external and internal responses of the cervical spine) under physiologic load vectors.

DESIGN: A three-dimensional (3D) anatomically accurate finite element model comprising of the C4-C5-C6 cervical spine unit including the three vertebrae, two interconnecting intervertebral discs, and the anterior and posterior ligament complex is used.

BACKGROUND: The effect of material property variations of spinal components on the human lumbar spine biomechanics is extensively studied. However, a similar investigation of the cervical spine is lacking.

METHODS: Parametric studies on the variations in the material properties of all the cervical spine components including the cortical shell, cancellous core, endplates, intervertebral disc, posterior elements and ligaments were conducted by exercising the 3D finite element model under flexion, extension, lateral bending and axial torsion loading modes. Low, basic and high material property cases for each of the six components under all the four physiologic loading modes were considered in the finite element analysis. A total of 432 results were evaluated to analyze the external angular rotation, and the internal stresses in the middle vertebral body, the superior and inferior endplates and the two intervertebral discs.

RESULTS: Variations in the material properties of the different cervical spinal components produced dissimilar changes in the external and internal responses. Variations in the material properties of the cancellous core, cortical shell, endplates and posterior element structures representing the hard tissues did not affect the external angular motion, and the internal stresses of the inferior and superior intervertebral discs under all four loading modes. In contrast, variations in the material properties of the intervertebral disc and ligament structures representing the soft tissues significantly altered the angular motion, and the stresses in the inferior and superior intervertebral discs of the cervical spine.

CONCLUSION: The material properties of the soft tissue structures have a preponderant effect on the external and internal responses of the cervical spine compared with the changes in the material properties of the hard tissue structures.

RELEVANCE: Bone remodeling (e.g., osteophyte) secondary to degeneration of the human cervical joints may be explained by a change in the material property of the soft tissues, coupled with an increase in stress (due to these material property variations) in the spinal components. Consequently, to accurately predict the biomedical effects of cervical spine degeneration, it is critical to accurately determine the material property of these components.

Author List

Kumaresan S, Yoganandan N, Pintar FA

Authors

Frank A. Pintar PhD Chair, Professor in the Biomedical Engineering department at Medical College of Wisconsin
Narayan Yoganandan PhD Professor in the Neurosurgery department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Adult
Biomechanical Phenomena
Cadaver
Cervical Vertebrae
Finite Element Analysis
Humans
Muscle Contraction
Muscle, Skeletal
Poisson Distribution
Range of Motion, Articular
Rotation
Stress, Mechanical