Helical computed tomography and three-dimensional reconstruction of a bipedicular developmental anomaly of the C2 vertebra

Study Design. a case of bilateral failure of fusion of the C2 neural arch r esembling a bipedicular fracture in a 9-year-old boy involved in a motor ve hicle accident. Objectives. To describe the use of helical computed tomography and three-di mensional reconstruction images to identify the defect as congenital. Summary of Background Data. Congenital defects in the C2 neural arch are ra re. Diagnostic difficulties arise when they are discovered during the asses sment of patients after trauma, when they may resemble C2 arch fractures. Methods. Lateral cervical spine radiograph, transverse section computed tom ography, and three-dimensional reconstruction images were used to delineate the anatomy of the defect. Results. The three-dimensional reconstruction views showed that normal alig nment of the vertebrae was maintained, despite the pedicle defects. Conclusions. Differentiation of a C2 fracture from a congenital defect may be difficult. Reconstruction in three dimensions from helical computed tomo graphy is a useful adjunct to conventional computed tomography in the evalu ation of such patients.