Sagittal measurements of the cervical spine in subaxial fractures and dislocations. An analysis of two hundred and eighty-eight patients with and without neurological deficits.

We analyzed three factors involved in fractures and dislocations of the cervical spine and their relation to the degree of injury of the spinal cord. The three factors were the space available for the spinal cord at the level of the injury, the sagittal diameter of the spinal canal at the uninjured levels, and the Pavlov ratio at the uninjured levels. Of the 288 patients analyzed, eighty-three had a complete injury of the spinal cord, ninety-two had an incomplete injury of the spinal cord, thirty had an isolated nerve-root injury, and eighty-three had no neurological deficit. The mean space available for the spinal cord at the level of the injury was 10.5 millimeters for the patients who had a complete injury of the spinal cord, 13.1 millimeters for those who had an incomplete injury of the spinal cord, 15.9 millimeters for those who had an isolated nerve-root injury, and 16.7 millimeters for those who had no neurological deficit. The difference between the groups was significant (p < 0.001) except for the difference between the patients who had an isolated nerve-root injury and those who had no neurological deficit. The mean sagittal diameter of the canal at the uninjured levels was 16.1 millimeters for the patients who had a complete injury of the spinal cord, 16.1 millimeters for those who had an incomplete injury of the spinal cord, 17.9 millimeters for those who had an isolated nerve-root injury, and 18.1 millimeters for those who had no neurological deficit. The difference between the patients who had a complete injury of the spinal cord and those who had an incomplete injury of the spinal cord and that between the patients who had an isolated nerve-root injury and those who had no neurological deficit were not significant (p > 0.05). However, the patients who had a complete injury of the spinal cord and those who had an incomplete injury of the spinal cord were significantly different from the patients who had an isolated nerve-root injury and those who had no neurological deficit (p < 0.001). The mean Pavlov ratio at the uninjured levels was 0.82 for the patients who had a complete injury of the spinal cord, 0.84 for those who had an incomplete injury of the spinal cord, 0.96 for those who had an isolated nerve-root injury, and 0.96 for those who had no neurological deficit.(ABSTRACT TRUNCATED AT 400 WORDS)