We developed a simple cooling method for spinal cord protection against ischemic injury during aortic surgery. The
neuroprotective effects of our method were investigated using an animal study. Selective spinal
hypothermia was produced by means of originally-designed cooling pads placed over the lower thoracic and lumbar vertebral column.
Spinal cord ischemia was induced by cross-clamping the thoracic aorta for 60 min in beagle dogs. The
neuroprotective effects were evaluated by a multi-modal study. The motor-evoked potentials of the spinal cord resulting from transcranial electric stimulation (MEPs) were recorded during both the ischemic and reperfusion periods. Hindlimb motor function was graded with the Tarlov score, and a histologic examination of the
spinal cord injury was performed, at 24 hours after
ischemia in animals undergoing
hypothermia (
hypothermia group: n = 7) or a
sham (control group: n = 7). The spinal cord temperatures at the lower thoracic (T10) and lumbar (L3) levels decreased by -9.1 degrees C per hour and -8.1 degrees C per hour, respectively. The amplitude of the MEPs decreased during
ischemia in both groups of animals, and significantly recovered during the early phase of aortic reperfusion in the
hypothermia group. The Tarlov scores in the
hypothermia and control groups were 3.3 +/- 1.0 and 1.1 +/- 1.5 (mean +/- SD, p = 0.015), respectively. Histopathologic study revealed that ischemic injury of the lumbar cord was reduced in the animals undergoing
hypothermia. Trans-vertebral regional cooling reduced ischemic
spinal cord injury in a canine study. The current method is potentially feasible for clinical use, especially in view of its technical simplicity and few procedure-related complications.