Management of combination fractures of the atlas and axis in adults.

STANDARDS There is insufficient evidence to support treatment standards. GUIDELINES There is insufficient evidence to support treatment guidelines. OPTIONS Treatment of atlas-axis combination fractures based primarily on the specific characteristics of the axis fracture is recommended. External immobilization of most C1--C2 combination fractures is recommended. C1--Type II odontoid combination fractures with an atlantodens interval of 5 mm or more and C1--hangman's combination fractures with C2--C3 angulation of 11 degrees or more should be considered for surgical stabilization and fusion. In some cases, the surgical technique must be modified as a result of loss of the integrity of the ring of the atlas.