Biomechanical Effect of Disc Height on the Components of the Lumbar Column at the Same Axial Load: A Finite-Element Study
Table 2
The von-Mises stress on the structures of the L4–5 spine in the flexion 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
1.6156
1.4583
1.3132
23.03∗
1.0364
1.1683
1.3132
−21.08
L5
1.2441
1.1806
1.1147
11.61∗
1.0202
1.0689
1.1147
−8.48
Cancellous bone
L4
0.0983
0.0935
0.0870
13.01∗
0.0785
0.0835
0.0870
−9.82
L5
0.0846
0.0878
0.0886
−4.48
0.0888
0.0888
0.0886
0.32∗
Posterior bone
L4
0.5045
0.5271
0.5514
−8.50
0.4352
0.5064
0.5514
−21.07
L5
0.6889
0.6768
0.6636
3.80∗
0.6376
0.6526
0.6636
−3.91
Endplate (upper)
L4–5
1.5277
1.3928
1.2242
24.79∗
0.8875
1.0533
1.2242
−27.50
Endplate (lower)
L4–5
0.9118
0.8047
0.7028
29.75∗
0.5642
0.6352
0.7028
−19.72
Disc (outer)
L4–5
0.1805
0.1714
0.1598
12.97∗
0.1434
0.1517
0.1598
−10.25
Disc (inner)
L4–5
0.0388
0.0370
0.0338
14.79∗
0.0283
0.0309
0.0338
−16.09
∗ indicates that a larger load than normal was received when the disc height was reduced by 50%.
