Absence of vasospastic response of the anterior spinal artery to subarachnoid blood.

Autologous blood (0.3 to 5.0 ml) was introduced into the lumbar subarachnoid space of nine monkeys. Serial spinal cord arteriography was performed at frequent intervals over a 24-hour period. Magnification techniques permitted direct measurement of the anterior spinal artery and posterior spinal vein. Neither immediate nor delayed spasm was observed in any animal. Similar techniques have routinely produced spasm of intracranial arteries in our laboratory.