C1-C2 posterior fixation: are 4 screws better than 2?

Background: Several types of C1-C2 fixation techniques have been described over the years in order to treat atlantoaxial instability.

Objective: To compare the pros and cons of the most popular C1-C2 posterior fixation used today: C1 lateral mass-C2 pedicle screw and rods (Harms) and transarticular screw (Magerl) fixations.

Methods: Retrospective review of 122 patients who underwent Harms or Magerl fixation for atlantoaxial instability.