Complication Avoidance and Management Using the O-arm for Odontoid Screw Fixation: Technical Note

Abstract

Objectives: Odontoid screw fixation is an accepted surgical approach for type 2 odontoid fractures with an intact transverse ligament. Typically, intraoperative bi-planar flouroscopy is used for placement of an odontoid screw. However, the quality of the images obtained with biplanar flouroscopy in the operating room is variable (due to patient body habitus) and screws may be misplaced. We report our technique for the use of the O-arm (Medtronic Navigation, Louisville, Colorado) to place and revise odontoid screw fixation. Methods and Results: The O-arm is sterilely draped into the surgical field. Intraoperative navigation is not needed. Using anteroposterior and lateral flouroscopic images obtained from the O-arm, the trajectory of the Kirschner wire, drill, tap, and screw can be visualized in real time. The final screw position can then be checked with a computed tomographic reconstruction view done with the O-arm while the patient is still draped sterilely in the operating room. We have utilized the Oarm to avoid a screw malposition in one patient with an odontoid fracture with osteopenia (which made visualization of the cervical spine difficult with standard flouroscopy). We have also utilized O-arm visualization to retrieve a malpositioned and migrated odontoid screw placed outside of our institution.