Hypothermic regional perfusion for protection of the spinal cord during periods of ischemia.

Ischemic spinal cord injury with resulting postoperative paraplegia is an inherent risk for operations on the thoracic aorta. The mechanism of injury is not clearly understood, and numerous adjuncts to avoid this complication have been suggested, with conflicting clinical results. A new technique of hypothermic regional perfusion of the spinal cord is described. Fifteen female pigs weighing 21 to 39 kg were used for the experiment. The control group consisted of 5 animals in which the thoracic aorta was clamped at the distal arch for 30 minutes. All of these animals sustained postoperative neurological damage. Eighty percent sustained postoperative paraplegia, and 20% had severe spasticity of the hind legs that precluded normal ambulation. The experimental group consisted of 10 animals in which hypothermic regional perfusion was performed for 30 minutes after cross-clamping of the distal arch. Perfusion cooling was followed by 30 minutes of ischemia in 5 animals and 45 minutes of ischemia in the remaining 5. All animals that underwent hypothermic regional perfusion were able to walk postoperatively, and no evidence of ischemic injury was found at postmortem examination of the spinal cords. This technique proved to be simple and effective in protecting the spinal cord for up to 45 minutes of ischemia in the experimental group. The clinical implications of this concept are promising for patients undergoing operations on the thoracic aorta.