Table 1 Material properties specified in the finite element models
Material | Elastic modulus (MPa) | Poisson ratio | Total element number | Cross section area (mm2) |
|---|---|---|---|---|
Cancellous bone | 100 | 0.2 | 18185 | - |
Cortical bone | 12000 | 0.3 | 6512 | - |
Endplate | 1000 | 0.4 | 2361 | - |
Nucleus pulposus | 10 | 0.4 | 1281 | |
Posterior elements | 3500 | 0.25 | 16587 | - |
Pedicle screw/cage | 110000 | 0.3 | 6388 | - |
Annulus fibre layers | ||||
Outermost | 550 | 0.3 | - | 0.7 |
Second | 495 | 0.3 | - | 0.63 |
Third | 440 | 0.3 | - | 0.55 |
Fourth | 420 | 0.3 | - | 0.49 |
Fifth | 385 | 0.3 | - | 0.41 |
Innermost | 360 | 0.3 | - | 0.30 |
Ligaments | ||||
Lig. long. posterius | 70 | - | - | 20 |
Lig. flava | 50 | - | - | 60 |
Lig. intertransversia | 50 | - | - | 10 |
Lig. interspinalia | 28 | - | - | 35.5 |
Lig. supraspinalia | 28 | - | - | 35.5 |
Lig. capsulae | 20 | - | - | 40 |