Most surgical endeavours are directed towards relieving stenosis of root canals or the spinal canal and/or stabilizing the spinal column. Correction of spinal curvatures is one of the major endeavours of spine surgeons. The spine can be regarded as two columns: anterior and posterior. The anterior column comprises the ligaments and bones back to the posterior longitudinal ligament (PLL) and the posterior column the elements posterior to the PLL. The spinal cord derives its blood supply from anterior and posterior longitudinal arteries arising from the vertebral arteries, and radicular arteries arising from the aorta. Trauma is the major cause of non-operative spinal cord injury (SCI) and, although vertebral fracture or dislocation is frequently present, SCI can occur when there is no radiographic abnormality. Epidural clonidine infusion has been shown to be effective and may avoid the possibility of staff attributing myelopathic symptoms to local anaesthetic effects.