Effect of impounder contact area on experimental spinal cord injury

The spinal cords of two groups of dogs were subjected to 500 gm-cm impacts using two different configurations of impounders. The impounders varied only in area of contact with the dural surface. All other parameters were kept constant. With one impounder all of the dogs injured were totally paraplegic. The impounder consistently producing total paraplegia straddled the entire width of the dorsal surface of the spinal cord in a manner corresponding to the posterior arch of a vertebra. The injury produced with this impounder is not only consistently reproducible but bears a closer resemblance to clinical injury such as anterior vertebral dislocation than that produced with a smaller impounder.