Influence of the type of atlantoaxial dislocation secondary to os odontoideum on sagittal alignment and balance of the subaxial cervical spine after posterior atlantoaxial fusion.

The direction/type of atlantoaxial subluxation correlates with the changes in lower cervical curvature after atlantoaxial fusion. Patients with atlantoaxial posterior dislocation and atlantoaxial instability are less likely than those with atlantoaxial anterior dislocation to develop loss of lordosis after posterior atlantoaxial fusion.