Preexisting severe cervical spinal cord compression is a significant risk factor for severe paralysis development in patients with traumatic cervical spinal cord injury without bone injury: a retrospective cohort study
STUDY DESIGN A retrospective imaging and clinical study. OBJECTIVE To evaluate the extraneural soft-tissue damage and its clinical relevance in patients with traumatic cervical spinal cord injury (SCI) without major bone injury. SUMMARY OF BACKGROUND DATA To date, various kinds of cervical discoligamentous injuries have been demonstrated on magnetic resonance images in patients with SCI without bony injury. However, it has not been clear whether these magnetic resonance imaging abnormalities are actually related to spinal segmental instability and the patients' neurological status. METHODS Eighty-eight adult patients with acute traumatic cervical SCI without major bone injury were examined by flexion-extension lateral radiographs and magnetic resonance images within 2 days after trauma. We excluded patients with flexion recoil injury; therefore, most of the patients included were considered to have sustained a hyperextension injury. Instability of the injured cervical segment was defined when there was more than 3.5-mm posterior translation and/or more than a 11° difference in the intervertebral angle between the site of interest and adjacent segments. The neurological status was evaluated according to the American Spinal Injury Association motor score. RESULTS On magnetic resonance images, the damage to the anterior longitudinal ligament and intervertebral disc were apparent in 44 and 37 patients, respectively. Various degrees of prevertebral fluid collection (prevertebral hyperintensity) were demonstrated in 76 patients. These magnetic resonance imaging abnormalities were significantly associated with initial cervical segmental instability as judged by flexion-extension radiographs. Interestingly, the American Spinal Injury Association motor score had a significant association with either magnetic resonance imaging abnormalities or segmental instability but not with the cervical canal diameter. CONCLUSION A considerable proportion of the patients with traumatic cervical SCI without major bone injury were shown to have various types of soft-tissue damage associated with cervical segmental instability at the early stages of the injury. The severity of paralysis greatly depended on these discoligamentous injuries.