The rationale for the use of CSF drainage is based on animal evidence that suggests that decreasing CSF pressure to less than 10 mm Hg during clamping of the thoracic aorta enhances perfusion of the spinal cord and decreases the risk for ischemic injury (6,15-17). While CSF drainage appears to be a promising intervention to reduce the incidence of paraplegia, there exists uncertainty as to the effectiveness of this intervention in human beings.

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The cerebrospinal fluid (CSF) pressure increases during clamping further decreasing the perfusion pressure of the spinal cord.

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 Draining CSF from the lumbar region may lessen the CSF pressure, improve blood flow to the spinal cord and reduce the risk of ischaemic spinal cord injury.