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

Objective: 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 bi-planar fluoroscopy 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 fluoroscopic 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 O-arm to avoid a screw malposition in one patient with an odontoid fracture with osteopenia (which made visualization of the cervical spine difficult with standard fluoroscopy). We have also utilized O-arm visualization to retrieve a malpositioned and migrated odontoid screw placed outside of our institution. Conclusions: Odontoid screw fixation and retrieval can be performed safely and efficiently using the O-arm. Our technique for use of the O-arm for this application does not require image guidance and replaces standard bi-planar fluoroscopy typically used for odontoid screw cases. Categories: General Surgery, Neurosurgery, Orthopedics