Spine
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Psychologic distress and low back pain. Evidence from a prospective study in the general population.
The present is a prospective population-based cohort study. ⋯ Symptoms of psychologic distress in individuals without back pain predict the subsequent onset of new episodes of low back pain. We calculate from these data that the proportion of new episodes of low back pain that might be attributable to such psychologic factors in the general population is 16%.
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This was a prospective study of patients (study group) with symptomatic disc herniations and asymptomatic volunteers (control group) matched for age, sex, and work-related risk factors. ⋯ In an age-, sex-, and risk factor-matched group of asymptomatic individuals, disc herniation had a substantially higher prevalence (76%) than previously reported in an unmatched group. Individuals with minor disc herniations (i.e., protrusion, contained discs) are at a very high risk that their magnetic resonance images are not a causal explanation of pain because a high rate of asymptomatic subjects (63%) had comparable morphologic findings. The only highly significant difference between the study group and control group regarding morphologic fi
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Retrospective cohort. ⋯ The present study findings suggest that disc degeneration may be explained primarily by genetic influences and by unidentified factors, which may include complex, unpredictable interactions. The particular environmental factors studied, which have been among those most widely suspected of accelerating disc degeneration, had very modest effects.
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Samples of human lumbar (L3-L4) anulus fibrosus from four different anatomic sites (anterior outer, posterolateral inner), ranging from normal to severely degenerate, were studied in uniaxial tension and measured for water content. ⋯ The dramatic changes in morphology, composition, and structure that occur in anulus fibrosus with aging and degeneration are accompanied by specific variations in the tensile properties, which were generally small in magnitude. Position of the anulus fibrosus within the intervertebral disc, particularly in the radial direction, appeared to be the most important variable affecting anulus fibrosus tensile properties. This dependence on position did not change with either aging or degeneration. Results from the present study may be useful in future finite element models to assess how altered material properties of the anulus fibrosus during degeneration and aging may affect the mechanics of the entire intervertebral disc.