Determining the probability of detecting cervical spine fractures with computed tomographic scans using the visible human database

Abstract

Cross-table lateral radiography alone is frequently unreliable for clearing of the cervical spine in cases of acute trauma. Computerized tomography (CT) is a standard procedure for detecting occult cervical spine fractures when cervical spine radiographs are equivocal or inadequate. There is evidence, however, that a significant number of fractures may still be missed by CT scans if too large a distance is used between scanning cuts in the axial plane. The purpose of this study was to determine the probability of detecting hidden fractures of the cervical spine over a wide range of fracture sizes and CT axial cut intervals. Digitized anatomic data of the cervical spine from the Visible Human ProjectTM of the National Library of Medicine were used as a model template for the study. From a series analysis, it was determined that use of the standard 5-mm cut intervals missed 25–75% of fractures, depending on the size of the lesion. The 4-mm cuts were able to detect all of the 3-mm lesions but still missed a significant number of the smaller fractures. The probability of finding occult fractures at the 3-mm axial interval was 100% for all except the smallest fracture sizes. This mathematical analysis suggests that computerized tomography is a less than optimal method for detecting occult fractures of the cervical spine unless the cut interval is 3 mm or less. The addition of sagittal plane reconstruction of these images would further enhance the ability to detect subtle subluxations or fractures.