Biomechanical responses to open experimental spinal cord injury.

This study evaluates the dynamic biomechanical responses of the cat spinal cord during experimental impact injury. Temporal deformations of the laminectomized spinal cord were recorded by a high speed camera (1500-3000 frames/sec). The cinematograph revealed large deformations, the cord being compressed to half its posterior-anterior diameter 7 msec after the onset of the impact. Peak impact force produced by a 20 gm mass falling from 15 cm height (300 GCF) averaged about 1.2 pounds, and the corresponding stress acting on the dural surface reached 42 pounds per square inch (or 2200 mm Hg). Both positive and negative pressure waves were found to be propagated in the cerebrospinal fluid.