Protection from postischemic spinal cord injury by perfusion cooling of the epidural space

To avoid devastating spinal cord injury during aneurysm operations, we evaluated the protective effects of epidural space perfusion cooling during occlusion of the descending thoracic aorta in a canine model. Sixteen dogs were divided into three groups: group 1 (n = 5) underwent 60 minutes of aortic occlusion without epidural space perfusion cooling; group 2 (n = 6), 60 minutes of occlusion with perfusion cooling; and group 3 (n = 5), 120 minutes of occlusion with perfusion cooling. The development of motor disturbance and its severity were examined 7 days after the procedure. In group 1, 1 dog was normal and 4 dogs showed spastic paraplegia with rigidly extended hind limbs. In group 2, 5 dogs were normal and 1 dog was unable to walk although it could move both of its hind legs slightly. In group 3, all 5 dogs were normal. Groups 2 and 3 had a significantly better neurologic outcome than group 1. Histologic examination of the spinal cord in dogs with paraplegia revealed degeneration of gray matter with macrophage infiltration. Histologic examination of the spinal cord in dogs without neurologic deficit showed enlargement of the central canal, light edema, and a small number of dark neurons. We conclude that epidural space perfusion cooling is effective in reducing the incidence of spinal cord injury after temporary occlusion of the descending thoracic aorta.