Identification and selective perfusion of the spinal cord-feeding arteriesby intrathecal pO(2) monitoring for spinal cord protection

Objectives: to study whether spinal cord-feeding arteries could be identifi ed by the changes in the intrathecal pO(2) (I-pO(2)), and to examine whethe r selective perfusion of feeding arteries identified by this method could p rotect the spinal cord against ischaemia. Design: controlled animal experiments. Materials and methods: in experiment 1, using 16 mongrel dogs, 18 segmental arteries were cannulated through which oxygenated saline was injected and the I-pO(2) change was observed. When the I-pO(2) increase was more than 0. 5 mmHg, the artery was considered to be a spinal cord-feeding artery. In ex periment 2, involving 10 dogs, the segmental arteries identified as spinal cord-feeding arteries were perfused with arterial blood and the recovery of I-pO(2) and evoked spinal potentials (ESP) was examined. Results: of 208 segmental arteries examined, 176 (84.6%) arteries were corr ectly judged and 32 (15.4%) were not. It was observed that the I-pO(2) reco vered from 13.9 to 30.5 mmHg and the ESP recovered from 20.9% and 8.2% to 6 6.5% and 44.7% of each control for the first negative (N1) and second negat ive (N2) components, respectively. Conclusion: spinal cord-feeding arteries were successfully identified using the I-pO(2) monitoring method. Perfusion of these arteries with arterial b lood improved the I-pO(2) and ESP, which were significantly depressed by is chaemia.