Evaluation of the lower spine after blunt trauma using abdominal computed tomographic scanning supplemented with lateral scanograms.

BACKGROUND: Patients at risk for thoracolumbar junction (TLJ) and lumbar spine (LS) injury after blunt trauma are classically evaluated using conventional radiographs. Frequently, these patients also undergo abdominal and pelvic computed tomographic (CT) scanning to exclude the presence of associated intra-abdominal injuries. Standard abdominal and pelvic CT scan usually includes an anteroposterior (AP) scout film (scanogram) obtained before the cross-sectional imaging. The objective of this study was to determine whether a lateral CT scanogram and axial CT views would provide adequate imaging to allow for evaluation of the TLJ and LS and therefore eliminate the need for conventional screening computed lumbar spine radiographs (CLSRs).

METHODS: Patients who sustained blunt injury and required both CLSRs as well as abdominal and pelvic CT scans were prospectively identified. The study protocol (CT + S) added lateral CT scanograms to all helical abdominal and pelvic CT scan studies. The AP and lateral CT scanograms were included with the axial images, and these views were reviewed together during final radiographic interpretation and diagnosis. The results of CT + S were compared with readings of the CLSRs (AP and lateral) in a blinded fashion by a trauma radiologist.

RESULTS: Lateral scanograms were generated for 71 patients. All scanograms were technically adequate, with image quality equal or superior to computed plain radiographs. Ten patients were found to have 20 fractures, 19 acute and 1 chronic. All abnormalities identified by plain radiographs were seen using CT + S (sensitivity, 100%; specificity, 100%). Eight transverse process and two spinous process fractures not seen on CLSRs were identified using CT + S.

CONCLUSION: Our CT + S protocol (axial CT images plus AP and lateral scanograms) outperformed screening CLSRs in the detection of fractures of the lower spine (TLJ + LS) after blunt trauma. In addition, scanogram imaging is less dependent on body habitus and adds no additional cost or time to abdominal and pelvic CT scanning. Further study is required to determine whether CT + S can routinely replace conventional radiographs of the lower spine after blunt trauma.