Abstract
Cervical pedicle screws (CPS) have superior strength to other approaches, but have a potential risk of neurovascular trauma. A navigation system is able to aid correct CPS insertion, but does not control final screw insertion. We inserted CPSs via a guide wire under navigation system control in 15 patients using cannulated screw system, and 56 CPSs were inserted. Postoperative CT scan was used to analyze the screw displacement, and Neo's classification was applied. Grade 2 and Grade 3 screw displacement was defined as mal-insertion, but no screw was found to be displaced. One screw was broken 3 months after the operation in a patient with athetoid cerebral palsy. Breakage of the guide pin did not occur. The advantage of a cannulated screw system is to reduce the probability of deviation of the CPS. However, it is necessary to be aware that the strength of the screw itself is weakened.
