Biomechanical Effect of Disc Height on the Components of the Lumbar Column at the Same Axial Load: A Finite-Element Study
Table 4
The von-Mises stress on the structures of the L4–5 spine in the lateral bending 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
1.432
1.409
1.416
1.14∗
1.467
1.422
1.416
3.62∗
L5
1.062
1.052
1.055
0.69∗
1.145
1.095
1.055
8.56∗
Cancellous bone
L4
0.083
0.078
0.074
12.24∗
0.071
0.073
0.074
−3.65
L5
0.093
0.091
0.089
4.37∗
0.091
0.090
0.089
2.54∗
Posterior bone
L4
0.449
0.494
0.542
−17.29
0.485
0.522
0.542
−10.51
L5
0.774
0.766
0.761
1.70∗
0.775
0.768
0.761
1.87∗
Endplate (upper)
L4–5
1.096
1.235
1.345
−18.51
1.346
1.354
1.345
0.04∗
Endplate (lower)
L4–5
0.540
0.513
0.507
6.36∗
0.544
0.519
0.507
7.19∗
Disc (outer)
L4–5
0.175
0.178
0.183
−3.94
0.187
0.186
0.183
2.53∗
Disc (inner)
L4–5
0.041
0.044
0.046
−10.23
0.046
0.047
0.046
0.34∗
∗ indicates that a larger load than normal was received when the disc height was reduced by 50%.
