Fractures of the dens in adult patients.

The series involves 42 consecutive acute fractures of the dens, of which 41 were treated nonoperatively. There were 26 Type II and 16 Type III fractures, as classified by Anderson and D'Alonzo. All Type III fractures and undisplaced or anteriorly displaced Type II fractures united. Posteriorly displaced Type II fractures had an overall nonunion rate of 50%, which increased to 75% if displacement was more than 5 mm. Eight patients died within 40 days after sustaining their fracture; seven had Type II fractures with an average of 10-mm posterior displacement. Seven patients with a Type II fracture had an associated atlas fracture; five of these patients died early. In Type II fractures, posterior displacement is an important prognostic factor for union and possibly for early mortality of elderly patients. In Type II fractures with an associated atlas fracture, the mortality rate is high. Nonoperative management, preferably halo-thoracic immobilization, is successful in all acute fractures of dens, except posteriorly displaced Type II fractures.