Figure 1 Preoperative, intra-operative, postoperative, 1 week and 9 weeks follow-up radiographs of a patient who had atlantoaxial dislocation caused by an old odontoid fracture treated with posterior atlantoaxial rod and screw fixation. (A–C) X-ray, CT, and MRI before the posterior atlantoaxial rod and screw fixation. (D) Intra-operative image of arthrolysis of atlantoaxial lateral mass. (E–G) CT and x-ray at 1 week after operation. (H) CT at 9 weeks after operation showed that strong fusion has been formed between the lateral mass joints. (I) One week after operation, CT showed the position of C1 pedicle screws on the left and right sides. (J, K) MRI at 1 week after operation showed that the compression of spinal cord has been relieved. CT – computed tomography; MRI – magnetic resonance imaging.