Anatomic Considerations for the Pedicle Screw Placement in the First Cervical Vertebra

The heights of the C1 pedicle, the posterior arch under the groove and the posterior lamina at the screw entry point are the major determinants for the possibility of placing pedicle screws in C1 of a given patient. This study indicates that it is feasible to place a 3.5-mm pedicle screw safely in C1 in most patients, and the lateral mass of C2 is a reliable anatomic landmark that can be easily identified to help the surgeon determine the optimal screw entry portal conveniently during surgery.