ULTRASTRUCTURAL EVIDENCE FOR ARTERIOLAR VASOSPASM AFTER SPINAL-CORD TRAUMA

OBJECTIVE: The primary objective of this study was to investigate the potential contribution of vasospasm to the cascade of secondary injury processes after traumatic spinal cord injury. Although ischemic facto rs have been implicated, in that vessel rupture, compression, and intr avascular thrombosis are readily identifiable, vasospasm has been more difficult to detect. METHODS: The sulcal arterioles in the ventral me dian fissure of the cervical spinal cord from adult rats were quantita tively examined at the ultrastructural level up to 24 hours after comp ression injury. RESULTS: There were statistically significant changes in the luminal cross-sectional area of sulcal arterioles after spinal cord injury, correlating directly with decreases in length and increas es in width of medial smooth muscle cells. A simple mathematical model of postinjury blood flow is presented, suggesting an 80% decrease cau sed by vasospasm alone. CONCLUSION: Our results clearly implicate vaso spasm as a contributing factor to secondary injury processes after tra umatic spinal cord injury.