Type-III dens fracture with distraction: an unstable injury. A report of three cases.

Abstract

Dens fractures have accounted for 7% to 17% of all fractures of the cervical spine in series of up to 625 cervical fractures1-5. In the classification system of Anderson and D'Alonzo, a type-III dens fracture extends downward into the cancellous portion of the body of the axis6 and typically heals without surgical intervention. After adequate reduction with traction, the use of a halo vest or halo cast has been associated with union rates of 80% to 100% in series ranging from twenty-one to 107 fractures1,4,5. Although displacement and/or dislocation2 of a dens fracture has been described in terms of translation or angulation, vertical displacement as a factor in determining stability or the adequacy of reduction has received little attention. Two case reports described vertical displacement of a type-III odontoid fracture7,8. Neurologic injury followed routine application of traction in both patients. The first patient became a ventilator-dependent quadriplegic, and the second died of complications from paralysis. The authors recommended aggressive surgical management when faced with this fracture pattern. We present the cases of three patients who had a type-III dens fracture with vertical displacement to describe the clinical, radiographic, and anatomic findings and to raise awareness of this rare but potentially devastating injury. In addition, we evaluated the clinical effectiveness of our treatment. Our hypothesis was that early recognition of this injury pattern and urgent surgical management provide the potential for functional survival. Our review of the cases was approved by our institutional review board, which waived the need for informed consent. We reviewed the cases of three patients with an acute traumatic type-III dens fracture and vertical displacement treated between 1998 and 2000. All three patients presented with vertical displacement of the dens on …