Table 1.
Material properties and element types of the spine soft tissues and hard tissues used in the finite element model
| Component | Element type | Young’s modulus (MPa) | Cross-section (mm2) | Poisson’s ratio |
|---|---|---|---|---|
| Bone | ||||
| Cortical bone | Shell elements | 10,000 | – | 0.29 |
| Cancellous bone | 3-D solid elements (4 node) | 100 | – | 0.29 |
| Disc | ||||
| Annulus (ground) | 3-D solid elements (8 node) | 4.2 | – | 0.45 |
| Annulus (fiber) | 3-D solid elements (8 node) | 450 | – | 0.30 |
| Nucleus | 3-D solid elements (8 node) | 1 | – | 0.49 |
| End plate | 3-D solid elements | 500 | – | 0.40 |
| Ligaments | ||||
| Anterior longitudinal ligament | 3-D tension truss elements | 30 | 33 | 0.30 |
| Posterior longitudinal ligament | 3-D tension truss elements | 20 | 33 | 0.30 |
| Ligamentum flavum | 3-D tension truss elements | 5 | 50.1 | 0.30 |
| Capsular ligaments | 3-D tension truss elements | 20 | 46.6 | 0.30 |
| Interspinous ligament | 3-D tension truss elements | 1.5 | 13 | 0.39 |
| Implants | ||||
| PEEK cage | 3-D solid elements (4 node) | 3600 | – | 0.30 |
| Titanium plate | 3-D solid elements (4 node) | 120,000 | – | 0.30 |
| Titanium screw | 3-D solid elements (4 node) | 120,000 | – | 0.30 |