Fig. 6

A 64-year-old female patient was admitted for weakness of both legs and walking instability for 9 months. Preoperative dynamic radiographs showed failed reduction of the atlantoaxial dislocation in a hyperextended or hyperflexed position (a, b), and after intraoperative traction, the atlantoaxial dislocation could still not be reduced, so it was classified as type III. Due to the high-riding vertebral artery, laminar screw fixation of the axis was performed (c, black arrow). At 2 months after operation, infection occurred (e, red arrow), and the internal fixation loosened and dislocated again (d). Debridement and anti-infection treatment were performed, the internal fixation was removed, and the head-ring brace was fixed (f, white arrow). Due to loosening of the original screw track, occipitocervical fusion was performed after infection control (g). The internal fixation position was acceptable at 3 months after operation, and bone graft healing was almost achieved (h, green arrow)