Effect of temporary visceral ischemia on spinal cord ischemic damage in the rabbit.

Background: Spinal cord ischemia and visceral ischemia may occur simultaneously during thoracoabdominal aortic aneurysm repair. The present rabbit study investigated the effect of a temporary interruption of the visceral perfusion on the development of ischemia-reperfusion injury of the spinal cord.

Methods: Spinal cord ischemia was induced by occlusion of the infrarenal aorta for variable durations (6 to 20 minutes) in 32 rabbits. In the visceral ischemia group, 20-minute concurrent clamping of the celiac trunk and mesenteric arteries was performed. At 24, 48, and 72 hours after ischemia, neurologic outcome was assessed in the control and visceral ischemia group. The PD50 (the duration of ischemia that produces lower limb neurologic deficits in 50% of the animals) was determined by quantal bioassay analysis. At 72 hours, histologic evaluation of spinal cord infarct size was performed.

Results: Compared with control animals, PD50 was significantly longer in the visceral ischemia group at 48 hours and 72 hours after ischemia. Neurologic and histologic outcomes correlated well (r = -0.90).

Conclusions: The results of the present rabbit study suggest that concurrent temporary visceral ischemia does not aggravate spinal cord ischemic injury in the rabbit. Moreover, the results suggest that concurrent visceral ischemia may increase the tolerance of the spinal cord to ischemic damage.