Experimental studies of brain and neck injury

Static and dynamic axial tension loads were applied to the intact and isolated cervical column of the monkey and human cadaver. Radioactive microspheres were used to evaluate brain and spinal cord perfusion in the monkey. To determine neural pathway damage, somatosensory evoked potentials were recorded with stimulation of sensorimotor cortex, and in spinal cord with stimulation of cauda equina. The evoked potential amplitude decreased prior to heart rate and blood pressure changes presumably due to brainstem distention. The preliminary studies show, 1) the brain and spinal cord were well perfused as measured with the microspheres when the evoked potentials decreased, 2) the cervical isolated cadaveric monkey spinal column ligaments failed statically at approximately 1/2 to 1/3 the force required for dynamic disruption, 3) in the intact monkey, the cervical ligaments failed statically at approximately 1/2 the dynamic failure force, 4) the isolated human cervical ligaments failed at loads approximately three times those observed in the isolated monkey cervical column.