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- Boström, Ola, 1963, et al.
(författare)
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A new neck injury criterion candidate-based on injury findings in the cervical spinal ganglia after experimental neck extension trauma
- 1996
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Ingår i: PROCEEDINGS OF THE 1996 INTERNATIONAL IRCOBI CONFERENCE ON THE BIOMECHANICS OF IMPACT, SEPTEMBER 11-13, DUBLIN, IRELAND. ; , s. 123-136
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Konferensbidrag (refereegranskat)abstract
- In this study a mathematical model, based on Navier Stokes equations, was developed and validated against experimental data. This model predicts the pressure changes in the spinal canal as a function of the volume change inside the canal during neck bending in the x-z (sagittal) plane. Another aim of the study was to investigate pressure phenomena and ganglion injuries at static neck extension loading and dynamic neck extension trauma with a head-restraint present. Experiments on pigs were conducted. Preliminary results indicate that ganglion injuries, as well as pressure transients inside the spinal canal, seem to correlate to the phase shift when the neck passes an s-shape (or maximal retraction) during the rearward motion of the head. That is, when the upper neck quickly changes from a flexion to an extension shape. Static loading of the neck resulted in no signs of injuries to the ganglia. A possible candidate for a neck injury criterion is presented, based on the relative acceleration between the top and the bottom of the cervical spine. A tolerance level based on the pig tests is also discussed.
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| 6. |
- Svensson, Mats Y., 1960, et al.
(författare)
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Pressure Effects in the Spinal Canal During Whiplash Extension Motion - A Possible Cause of Injury to the Cervical Spinal Ganglia
- 1993
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Ingår i: Proceedings of the International Research Committee on the Biomechanics of Impacts (IRCOBI) conference, Eindhoven, Netherlands. ; , s. 189-200
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Konferensbidrag (refereegranskat)abstract
- impact-velocities (<20 km/h) often cause pain in the neck region as well as a number of other neurological symptoms, most of which can be related to the nerve paths that pass through the cervical intervertebral foramina. When the neck is flexed or extended in the sagittal plane the length of the cervical spinal canal alters but the cross-sectional area of the canal remains almost constant. During flexion-extension motion of the cervical spine, the size of the inner volume of the spinal canal will change. Since the tissues inside the canal can be considered incompressible, an alteration will take place of either the amount of cerebro spinal fluid or the amount of blood in the veinplexa of the epidural space, or both. This requires fluid transportation through the intervertebral foramina as well as along the spinal canal. During a whiplash extension motion, the flow velocity can be expected to rise far above physiologically normal levels and pressure gradients can thus be expected to occur. In turn, the soft tissues inside and around the cervical spine and particularly in the intervertebral foramina will sustain mechanical strain and stress. Anaesthetised pigs were exposed to a swift extension-flexion motion of the neck while the pressure inside the spinal canal and the skull was measured. Pressure pulses of magnitudes up to 150 mmHg (20 kPa) were observed during the motion. The magnitude of pressure is for each moment dependent on the position of the neck, the velocity and the acceleration of the motion. Plasma membrane dysfunction was indicated by the results from light microscopic analyses of the cervical and the three upper thoracic spinal ganglia revealing the staining of nerve cells and satellite cells by protein complexed to the Evans Blue dye.
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| 7. |
- Örtengren, Tore, et al.
(författare)
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Membrane leakage in spinal ganglion nerve cells induced by experimental whiplash extension motion: a study in pigs
- 1996
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Ingår i: Journal of Neurotrauma. - : Mary Ann Liebert Inc. - 0897-7151 .- 1557-9042. ; 13:3, s. 171-180
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Tidskriftsartikel (refereegranskat)abstract
- Nerve cells in the cervical and upper thoracic spinal ganglia were examined for possible plasma membrane leakage, as revealed by their ability to exclude a dye-protein complex, after experimentally induced whiplash in a pig model system. The rationale for this approach is found in the fact that the interstitium of spinal ganglia differs from most other parts of the nervous system in that it lacks a barrier, allowing blood constituents to gain access. The dye Evans blue, which rapidly conjugates with blood proteins, is found in the interstitium of normal spinal ganglia after intravenous injection, but it is excluded from the nerve cells and their enveloping satellite cells. In contrast, after a simulated whiplash extension trauma many of the nerve cells were stained, reflecting the inability of their plasma membranes to exclude the dye-protein complex. Morphometric measurements revealed that the highest frequency of cellular dye uptake was observed in the C4-C7 spinal ganglia (mean 16 - 18%; range 5-27%). The blood-nerve barrier of the adjacent nerve fascicles remained intact, with rare exception. Several factors are considered to contribute to the induction of these cell abnormalities in the spinal ganglia after an experimentally induced, simulated whiplash trauma in this pig model system.
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