Table 1 Materials properties and element types in the finite element models
Materials | Element type | Young’s modulus (MPa) | Poisson’s ratio (µ) |
|---|---|---|---|
Cortical bone | C3D4 | 12,000 | 0.3 |
Cancellous bone | C3D4 | 100 | 0.2 |
Bony endplate | C3D8I | 1,200 | 0.29 |
Cartilage endplate | C3D8I | 24 | 0.4 |
Nucleus pulposus | C3D8H | C10 = 0.12, C01 = 0.09, D = 0 |  |
Annulus ground | C3D8H | C10 = 0.1333, C01 = 0.0333, D = 0.6 |  |
Annulus fiber | T3D2 | 360–550 |  |
Anterior longitudinal | T3D2 | 7.8 (< 12), 20 (> 12%) |  |
Posterior longitudinal | T3D2 | 10 (< 11%), 20 (> 11%) |  |
Ligamentum flavum | T3D2 | 15 (< 6.2%), 19.5 (> 6.2%) |  |
Supraspinous | T3D2 | 8.0 (< 20%), 15 (> 20%) |  |
Interspinous | T3D2 | 10 (< 14%), 11.6 (> 14%) |  |
Intertransverse | T3D2 | 10 (< 18%), 58.7 (> 18%) |  |
Capsular | T3D2 | 7.5 (< 25%), 32.9 (> 25%) |  |
Screws and rods | C3D4 | 110,000 | 0.3 |
Cage | C3D8 | 3,600 | 0.25 |
Bone grafts | C3D8 | 100 | 0.2 |