Lamellar and Interlamellar Shear Compared Across Regions of the Annulus Fibrosus
Computational models of the intervertebral disc commonly use continuum descriptions that treat the annulus fibrosus as a single material rather than discretely modeling the lamellae and interlamellar interactions [1,2]. However, modeling the mechanics of individual lamellae and the interlamellar region can aid in the understanding of degenerative disc disease and its treatment. Previous work has demonstrated that fibrous connections between lamellae as well as bridges spanning across layers exist, but the mechanical contributions of these structures have largely remained uncharacterized [3]. Studying interlamellar shear mechanics may provide insights into the structure-function relationships of the annulus. The purpose of this study was to compare the mechanical shear in the interlamellar and lamellar regions, model the stress-stretch relationships of these areas utilizing a hyperelastic strain energy function, and compare the shear properties across multiple locations of the intervertebral disc.