Article

Previous studies reported that, in non-degenerate discs, the nucleus
pulposus migrates posteriorly during flexion and anteriorly during extension
within the intervertebral disc. However, in these studies the differences between
anterior and posterior distances have been regarded as an indicator of nucleus
pulposus migration. This study investigated the reality of migration of the
nucleus pulposus within the intervertebral disc with changing postures. METHOD:
Magnetic resonance images were obtained of the lumbar spines of 25 asymptomatic
volunteers in sitting, standing and supine postures. The anterior and posterior
height of the intervertebral disc, the anterior -posterior length of the
intervertebral disc and nucleus pulposus, and the positions of the anterior and
posterior margins of the nucleus were measured from mid-line sagittal images.
FINDINGS: Changing postures altered the anterior and posterior height of the disc
and three types of morphological changes, including changes in the anterior
-posterior lengths of the intervertebral disc and nucleus pulposus, together with
the position of the nucleus in the disc were found. The length of the
intervertebral disc and nucleus pulposus changed under the variations in spinal
loading caused by posture. INTERPRETATION: The results of this study indicated
that the apparent nucleus pulposus migration within intervertebral disc is
actually deformation of the nucleus pulposus length which depends on posture and
the magnitude of the load. In other words, adopting different postures deforms
the nucleus pulposus and therefore, changes the position of the nucleus pulposus
but there is no apparent nucleus pulposus migration within the intervertebral
disc.
CI - Copyright (c) 2011 Elsevier Ltd. All rights reserved.

Langue : ANGLAIS