A pilot study of warm versus cold perfusion and preservation was completed in 32 patients prior to the ongoing study. The findings of the pilot study showed 53 percent of patients had evidence of new neurologic disturbance at postoperative day four. Only the neurologic dysfunction could be correlated with warm versus cold perfusion (37.5 percent warm versus 75 percent cold, P less than 0.05). The changes in neurologic function had abated or clearly improved by one month of follow-up, and the distinction in neurologic dysfunction grading was no longer apparent between the two groups.