Utility of flexion and extension radiographs of the cervical spine in the acute evaluation of blunt trauma

Background: The purpose of this study is to investigate the usefulness of flexion and extension radiographs of the cervical spine for the acute evaluation of ligamentous injury in cases of awake blunt trauma. Methods: A review of 106 consecutive cases of blunt trauma evaluated with flexion and extension radiographs of the cervical spine obtained in the acute setting at a Level I trauma center was performed. The data compiled included the age, sex, mechanism of injury, type of radiographic evaluations, interpretation of all radiographic studies, and clinical outcome on follow-up. Results: Sixty-six of the patients (62%) were involved in motor vehicle crashes. Other injuries included 15 falls (14%), 9 blunt assaults (8.5%), and 16 other types of blunt trauma (15%). Thirteen cervical spine injuries were diagnosed in 9 of 106 patients (8.5%). Injuries included two fractures, eight acute disc herniations, two ligamentous injuries, and one cord contusion diagnosed on the basis of all radiologic evaluation and clinical follow-up. Seventy-four patients (70%) had a range of flexion and extension motion interpreted as adequate for diagnostic purposes. Five of the 74 patients (6.75%) with an adequate range of motion had cervical spine injuries. No ligamentous injuries were misdiagnosed in this group. Thirty-two of the flexion and extension examinations (30%) were interpreted as inadequate because of limited motion. Four of the 32 patients (12.5%) with inadequate flexion and extension examinations had injuries subsequently detected on cross-sectional imaging (computed tomographic scanning or magnetic resonance imaging) including severe ligamentous injury. Conclusion: When adequate motion was present on flexion and extension radiographs, the false-negative rate was zero in this study. However, in the acute setting, 30% of the examinations were limited by inadequate motion. A higher percentage of injury (12.5%) was detected by subsequent cross-sectional imaging in these patients. Limited flexion and extension motion on physical examination should preclude the use of flexion and extension radiographs, as they are of limited diagnostic utility. Cross-sectional imaging may be warranted in this high-risk group of patients.