Spinal cord tissue changes due to residual compression in a novel rat contusion model

• Main Author: Sjovold, Simon Gerhard
• Language: English
• Published: 2010
• Online Access: http://hdl.handle.net/2429/17765

Residual compression can potentially lead to the exacerbation of the initial spinal cord trauma and is currently corrected by performing surgical decompression. Decompression is one of the few treatment options currently available to clinicians, but until direct beneficial effects are proven, its use will remain controversial. Many investigators have developed experimental models to evaluate the effects of maintained compression; however replication of the clinical injury incorporating a primary contusion followed by residual compression of the spinal cord has not been a primary focus. The objectives of this thesis were to i) establish injury protocols of graded residual compression following a reproducible contusion injury, ii) develop a clamp to rigidly support the thoracic vertebrae, iii) develop a method to monitor the long-term microvascular blood flow of the spinal cord, and iv) determine the influence of 40% and 90% residual spinal cord compression on the extent and progression of neurological damage following a moderate contusive spinal cord injury. The initial contusion produced considerable disruption of the localized tissue, preventing it from supporting further compression. As a result, the load relaxation of the spinal cord was rapid for both levels of residual compression. Contusion did not adversely affect the microvascular blood flow, but residual compression significantly increased the blood flow one level caudal to the injury epicentre. Total haemorrhage volume was similar for contusion and both levels of residual compression although the extent was greater following 90% residual compression. High levels (90%) of residual compression resulted in an extension of the gray and white matter damage beyond that of the initial contusion injury. Low levels (40%) of residual compression did not appear to increase the cellular damage in the white and gray matter, at least in the acute stage (initial 3 hours). Although this thesis did not evaluate the blood flow in all regions of the spinal cord and only compared two levels of residual compression for a contusion injury of a single magnitude, we have produced compelling evidence that residual compression does not entirely restrict the blood Abstract flow through the cord. distant to the injury. As well, the relative magnitude of the residual compression, in relation to the initial contusion injury, is an important factor in determining the resulting level of neurological injury. === Applied Science, Faculty of === Mechanical Engineering, Department of === Graduate