Nonlinear Poroelastic Analysis of Lumbar Motion Segments in Prolonged Compression Postures

Abstract A prominent loading condition for the human spine is the exposure to prolonged postures. In a growing number of occupations, the workers are confined to perform activities with static postures. Epidemiological studies have identified the static work postures in sedentary and driving occupations as a risk factor in low-back disorders and have suggested that the risk increases in very sedentary as well as very heavy occupations [1]. The mechanism for the former association, however, is not yet known. This work aims to analyze the temporal response of a lumbar motion segment in compression using a 3-D nonlinear poroelastic finite element study. Effects of the compression magnitude, coupled sagittal rotation, strain-dependent variable permeability, boundary pore pressure, end-plate permeability, and some surgical interventions on the temporal response are studied with special attention on the facet forces and disc stresses.