Objective assessment of CNS function within 6 hours of spinal cord ischemia in rabbits

Purpose To develop a neurologic scoring (NS) system to objectively assess CNS function shortly after spinal cord ischemia. Methods Spinal cord ischemia was induced by temporarily clamping the infrarenal aorta in 27 rabbits anesthetized with isoflurane/N₂O/O₂ without muscle relaxants. Animals were divided ito group I, normothermic ischemia [I-a, 11 min (n=8); I-b, 12 min (n=8)], and group II, 60 min hypothermic ischemia targeted to II-a, 29.5°C (n=5), and II-i, 30.0°C (n=6). Postischemic neurologic function was scored from 0 to 6. Results Seventy-five percent of each group I subgroup ended with paraplegia. Function in the I-b group tended to be worse than in I-a (NS=1.7vs 1.9P>0.05). Hypothermia of 29.9±0.1°C protected partially (NS=2.8), whereas 29.4±0.1°C resulted in significantly higher NS, starting at 150 min (P<0.05vs IIi) with total recovery 5.5 hours (P<0.0001) post re-perfusion. Conclusions Protection of the spinal cord from ischemia can be objectively quantitated by our system. Protection strategies can be compared within 6 h of the ischemia-insult.