Disc pressure measurements. x

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Nachemson AL. x Spine. [JC:uxk] 6(1):93-7, 1981 Jan-Feb. x By measurement of intradiscal pressure in vitro, the hydrostatic x properties of the nucleus pulposus of normal lumbar intervertebral disc x were proven. The hydrodynamic properties seem to exist also in the x somewhat degenerated disc, but not in the more severely deranged ones. x Intravitally-performed measurements of disc pressure over the last 20 x years in more than 100 individuals have demonstrated how the load on the x lumbar disc varies with the position of the subject's body and during the x performance of various tasks, both in standing and in sitting. Compared x with the pressure of load in the upright standing position, reclining x reduces the pressure by 50-80%, while unsupported sitting increases the x load by 40%, forward leaning and weight lifting by more than 100%, and the x position of forward flexion and rotation by 400%. Large augmentations in x pressure were also observed in subject performing various commonly x prescribed strengthening exercises. x