Functional outcome following teardrop fracture of the axis

The teardrop fracture of the axis comprises a special entity, characterized by an avulsed fragment, of varying size, from the anterior inferior angle of the body of C2. It is extremely rare and differs in many respects from the teardrop fracture of the lower cervical spine, which was originally described by Schneider and Kahn in 1956. Indeed, much of what is written about teardrop fractures relates to lower cervical spine flexion type teardrop fractures. To date there are only 36 reported cases of teardrop fracture of the axis. We present seven cases of a teardrop fracture of the axis treated in the National Spinal Injuries unit at the Mater Miscericordiae University Hospital, Dublin from 1993 to 2003. The mean follow-up time was 6 years. The stability of this fracture has been questioned by certain authors, resulting in disagreement concerning the best choice of treatment to be followed. The radiological, clinical features and functional outcome of patients who have sustained a teardrop fracture of the axis will be described. The mechanism of injury and potential for instability will be compared with teardrop fractures of the lower cervical spine so as to emphasize the importance of recognizing this injury as a separate entity.