When several fracture types are present in the upper cervical spine, the choice of treatment will be determined by the most severe (unstable) fracture.
In the most cases, this means that that the posterior procedure is performed.
One example is the combination of an odontoid fracture with a fracture of the posterior arch of C1. In this case the odontoid cause the most instability. In order to address both fractures, the posterior C1-C2 fixation is indicated.