Biomechanical Effect of Disc Height on the Components of the Lumbar Column at the Same Axial Load: A Finite-Element Study
Table 5
The von-Mises stress on the structures of the L4–5 spine in the axial rotation mode when the disc height was reduced to 75% and 50% compared to normal (100%).
Component
The 50% anterior disc model, MPa (a)
The 75% anterior disc model, MPa (b)
The 100% anterior disc model, MPa (c)
Rate of change [(a-c)/c ∗ 100] (%)
The 50% posterior disc model, MPa (d)
The 75% posterior disc model, MPa (e)
The 100% posterior disc model, MPa (f)
Rate of change [(d-f)/f ∗ 100] (%)
Cortical bone
L4
0.781
0.772
0.809
−3.48
0.982
0.877
0.809
21.45
L5
1.249
1.240
1.239
0.86∗
1.282
1.254
1.239
3.50∗
Cancellous bone
L4
0.069
0.064
0.059
17.71∗
0.053
0.056
0.059
−9.58
L5
0.091
0.090
0.088
2.33∗
0.089
0.089
0.088
0.08∗
Posterior bone
L4
0.388
0.457
0.524
−25.98
0.488
0.513
0.524
−6.89
L5
1.195
1.198
1.203
−0.74
1.205
1.205
1.203
0.12∗
Endplate (upper)
L4–5
0.420
0.466
0.629
−33.18
0.856
0.747
0.629
36.12∗
Endplate (lower)
L4–5
0.376
0.342
0.331
13.67∗
0.378
0.343
0.331
14.23∗
Disc(outer)
L4–5
0.125
0.122
0.118
5.88∗
0.122
0.121
0.118
3.26∗
Disc(inner)
L4–5
0.024
0.023
0.024
0.38∗
0.026
0.025
0.024
11.09∗
∗ indicates that a larger load than normal was received when the disc height was reduced by 50%.
