Journal of neurotrauma
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Journal of neurotrauma · Mar 1992
ReviewExperimental models for spinal cord injury research: physical and physiological considerations.
This paper describes historical and current experimental models used to develop our current understanding of the biomechanics and pathophysiology of traumatic spinal cord injury; the advantages and limitations of current experimental models; considerations for selecting an appropriate injury model based on experimental objectives; and key physiological factors in the spinal cord injury response that may interact with the injury response and alter the outcome. All of the above must be considered in the development and selection of an appropriate experimental injury model that meets specific needs. Various experimental models have been developed to study spinal cord injury and the pathophysiological and physical mechanisms responsible for tissue damage and loss of function. ⋯ Also, experimental techniques, especially anesthesia, and surgical procedures, should be carefully reviewed for interactions with the injury response or potential therapeutic interventions to ensure validity of interpretation. It is hoped that data correlating physical spinal cord injury parameters with functional outcome will ultimately be combined with data on vertebral injury and spinal failure mechanics to further our understanding of clinical injury. Such approaches should lead to interventions that reduce the incidence and severity of traumatic human spinal cord injury.
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Spinal cord injury models continue to be used to learn more about the pathophysiology of injury as well as potential therapeutic interventions. Most researchers now rely on rat models of injury with injury produced by impact, compression, or even photochemical techniques. A number of laboratories have confirmed that reproducible and graded injury can be produced in the rat with outcome monitored by behavioral, neurophysiologic, and morphologic analyses. ⋯ In addition, a new approach to therapy is being explored via implantation of cells into the injured spinal cord. Cell suspensions can be implanted in clinically relevant injury models without exacerbating the effects of injury and with some indications of beneficial effect. The potential usefulness of such an approach is just beginning to be evaluated.
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Journal of neurotrauma · Mar 1992
ReviewControl of intracranial pressure in patients with severe head injury.
Raised intracranial pressure (ICP) occurs at some time in 50-75% of severely head injured patients. Measurement of ICP alone is not sufficient. Arterial pressure must also be monitored: the important physiological variable is cerebral perfusion pressure. ⋯ Additional measurements of importance include brain electrical activity, arterial and jugular venous oxygen saturation, and blood flow velocity in major intracranial arteries measured by transcranial Doppler sonography. These assessments not only add information about the cause of intracranial hypertension (vascular vs. nonvascular) but also help to regulate therapy, providing early warning that a treatment for reducing the ICP is actually producing global brain ischemia. In the management of raised ICP, all correctable factors must first of all be dealt with, then a choice made between hypnotic drugs and osmotic therapy according to whether the cause of raised ICP is, respectively, vascular or nonvascular.
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The authors review acute and delayed traumatic intracerebral hemorrhages. Based on recent experimental and clinical data, these injuries' clinical presentation, pathologic characteristics, and treatment are discussed. A description of traumatic hemorrhage based on biomechanics is emphasized.
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General categories of experimental brain injury models are reviewed regarding their clinical significance, and two new models are presented that use different methodology to produce injury. This report describes and characterizes the pathophysiologic changes produced by a novel fluid percussion (FP) method and a controlled cortical impact (CI) technique, both developed at the General Motors Research Laboratories (GMRL). The new models are compared to prior experimental brain injury techniques in relation to ongoing physical and analytical modeling used in automotive safety research by GMRL. ⋯ These controlled variables enable the amount of deformation and the change in deformation over time to be accurately determined. In addition, the CI model produces graded, reproducible cortical contusion, prolonged functional coma, and extensive axonal injury, unlike the FP technique. The quantifiable nature of the single mechanical input used to produce the injury allows correlations to be made between the amount of deformation and the resultant pathology and functional changes.(ABSTRACT TRUNCATED AT 400 WORDS)