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 |