New spinal cord injury model produced by spinal cord compression in the rat

Graded spinal cord injuries were produced in rats by compressing the spinal cord at the level of the T11 vertebra for 5, 15, 30, 60, or 180 min with stainless steel screws of 2-mm diameter and 2.8-mm length, or for 60 min with screws of the same diameter and various lengths (2.5, 2.8, 3.1, or 3.4 mm). The main neurologic symptoms caused by spinal cord compression were motor deficits, sensory deficits, and urinary incontinence. Neurologic scores, based on both motor and sensory deficits, correlated significantly with both the screw length and the duration of compression at every observation point from 4 hr to 21 days after removal of the screw. The incidence of urinary incontinence (from 24 hr to 21 days) and the percentage of rats surviving (from 14 days to 21 days) also correlated closely with the two factors (screw length and duration of compression). These results suggest that the present procedure could be a useful and simple model for studying traumatic spinal cord injury in rats.