Biomechanical effect of intervertebral disc degeneration on the lower lumbar spine.
Comput Methods Biomech Biomed Engin
; 26(14): 1669-1677, 2023.
Article
em En
| MEDLINE
| ID: mdl-36218332
ABSTRACT
Lumbar intervertebral disc degeneration can induce bone hyperplasia, lumbar intervertebral disc herniation and other diseases, is one of the causes of low back pain, which seriously affects people's quality of life. And the causes of degeneration are very complex, so it is essential to understand the underlying mechanism of intervertebral disc degeneration and its influence. In this study, biomechanical effects of L4â¼L5 lumbar degeneration with different degrees of degeneration were studied based on the numerical simulations. The three-dimensional finite element model of normal L2â¼S1 lumbar vertebrae was established based on CT images of average adult male and verified. Several key parameters (intervertebral disc height, nucleus pulposus size, properties of different materials, etc.) of the model were modified to construct L4â¼L5 models with different degrees of degeneration (grade 1, grade 2, grade 3, and grade 4). The range of motion (ROM), the intradiscal pressure of the nucleus, and the maximum Von Mises stress were determined by applying torques in different directions to simulate the four postures of flexion, extension, lateral bending, and axial rotation under compression load (500 N) to simulate the upper body weight of the human body. In different postures, with the increase of L4â¼L5 degeneration degree, the ROM of the L4â¼L5 degeneration segment showed a decreasing trend (Grade 4 had decrease of 41.9% to 65.2% compared to normal at different postures), while the ROM of its adjacent normal segments showed an increasing trend (L3â¼L4 Grade 4 had increase of 21%-94% compared to normal at different postures; L5â¼S1 Grade 4 had increase of 32%-66% compared to normal at different postures). With the increase in the degree of degeneration, nucleus pulposus pressure in the L4â¼L5 degeneration segment decreased continuously under different postural conditions (Grade 4 had decrease of 25%-134.6% compared to normal at different postures), while the nucleus pulposus pressure in adjacent normal segments (L3â¼L4 and L5â¼S1) showed a gradually increasing trend. The maximum Von Mises stress of the three segments increased with the increasing degree of degeneration at different postures (L4â¼L5 Grade 4 increased to 1.75 â¼ 4 times compared to normal at different postures). In four different models of lumbar disc degeneration, the adjacent normal segment of the disc compensates for the movement and loading pattern of the degenerated segment. At the same time, the load pattern inside the degenerated segment also changes.
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MEDLINE
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En
Ano de publicação:
2023
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Article