FRACTURES OF THE C-2 VERTEBRAL BODY

Vertical C-2 body fractures are presented in 15 patients with clinical and imaging correlations that suggest the existence of a variety of m echanisms of injury. In these patients, clinical and imaging correlati ons were derived by: 1) defining the point of impact by clinical exami nation; 2) defining the point of impact by soft-tissue changes on cran ial magnetic resonance (MR) imaging or computerized tomography (CT); 3 ) obtaining an accurate history of the mechanism of injury; and 4) spi ne imaging (x-ray studies, CT, and MR imaging) of the C-2 body fractur e and surrounding bone and soft tissue. The cases presented involve th e region located between the dens and the pars interarticularis of the axis. Although these fractures are rarely reported, they are not unco mmon. An elucidation of their pathological anatomy helps to further th e understanding of the mechanistic etiology of upper cervical spine tr auma. A spectrum of mechanisms of injury causing upper cervical spine fractures was observed. The type of injury incurred is determined pred ominantly by the force vector applied during impact and the intrinsic strength and anatomy of C-2 and its surrounding spinal elements. From this clinical experience, two types of vertical C-2 body fractures are defined and presented: coronally oriented (Type 1) and sagittally ori ented (Type 2). A third type of C-2 body fracture, the horizontal rost ral C-2 fracture (Type 3), is added for completeness; this Type 3 frac ture is the previously described Type III odontoid process fracture de scribed by Anderson and D'Alonzo.