P17 - Biomechanical Comparison of C1 Lateral Mass C2 Pars and C3 Lateral Mass Screw-Rod Construct vs C1 Lateral Mass C2 Pedicle Screw Fixation for Type II Odontoid Fractures

Abstract

BACKGROUND CONTEXT: Rigid fixation of the atlantoaxial complex in the setting of a type II odontoid fracture is required for successful fusion and fracture healing. The C1 lateral mass—C2 pedicle screw-rod construct (Harms technique) provides excellent C1-C2 fixation and is associated with high rates of fusion. However, C2 pedicle screw placement is challenging due to the risk of vertebral artery injury and is prohibited if the vertebral artery follows an aberrant course. Alternatively, the use of C2 pars screws may be a safer option but may come at the cost of reduced C1-C2 immobilization. Therefore, the hypothesis of this study is that extending the C1 lateral mass—C2 pars screw-rod construct with C3 lateral mass screws will mitigate the risk of vascular injury without compromising C1-C2 fixation.