Dynamic respond of stresses in lumbar vertebrae during getting up / 医用生物力学

ABSTRACT

Objective To reveal the characteristics of dynamic response from stresses in lumbar intervertebral discs during getting up. Methods A finite element model of lumbar vertebrae (L1-5) with consideration of nonlinear and anisotropic material properties was established and validated by comparing the experimental data. Based on this model, the complete process of getting up from supine lying, rising and turning left to sitting up on the bedside were simulated, and the distributions and dynamic changes of stresses in the model during getting up were calculated. Results The stress and its distributions in annulus fibrosus, nucleus pulposus, and endplate of lumbar vertebrae during getting up changed constantly. The stresses were mainly concentrated on the dorsal part of lumbar vertebrae, and the maximum stress was located at L4-5 intervertebral disc. Peak stresses occurred when the body trunk turned about 35° -62° from supine lying, which were 3 times and 17 times of those during sitting firmly and supine lying, respectively. Conclusion As a high incidence area of injury and degeneration, the dorsal part of L4-5 intervertebral disc in daily activities may be subjected to an extensive stress, which is higher than that predicted by static experiments and calculations. Dynamic simulation can help to further understand the loading characteristics of intervertebral discs and provide a scientific reference for prevention and treatment of related lumbar disease.