Impact of sacroiliac interosseous ligament tension and laxity on lumbar spine biomechanics under vertical vibration: a finite element study.

Abstract

Objective: To investigate the impact of tension and laxity in the sacroiliac interosseous ligament on lumbar spine displacement and force response in vibration environments.

Methods: A finite element model of the lumbar-pelvis, previously crafted and rigorously validated, was used to simulate ligament tension and laxity by adjusting the elastic modulus of the SIL under a sinusoidal vertical load of ±40 N at 5 Hz. Comparisons of lumbar spine horizontal and axial displacements as well as annulus fibrous stress, nucleus pulposus pressure, and facet joint force were performed, respectively.

Results: With the elastic modulus of the SIL varying by +50, -50, and -90%, the maximum vibration amplitude changed by +20.00, -175.00, and -627.27% for lumbar horizontal displacement, +30.00, -157.14, and -627.22% for lumbar axial displacements, +5.88, -19.35, and -245.16% for annulus fibrous stress, +10.00, -25.00, and -157.14% for nucleus pulposus pressure, as well as +6.54, -20.13, and -255.37% for facet joint force, respectively.

Conclusion: In contrast to static environments, large laxity of the SILs not only diminishes lumbar spine stability in vibrational settings but also significantly amplifies dynamic loads, thereby heightening the risk of lumbar spine vibratory injuries and low back pain disorders.