Fig. 3
An illustrative case. A 36-year-old man presented with weak limbs and unstable motion. A Preoperative computed tomography (CT) showed an increased atlanto dental interval, C1 occipitalization, C2-3 fusion, bilateral atlantoaxial lateral joints tilted forward, an almost vertical left articular surface. B, C High-riding vertebral arteries on both sides. The medial height of the right side is 5.5 mm. The height of the isthmus is 3 mm. The medial height of the left side is 5 mm. The height of the isthmus is 2 mm. D Bilateral pedicle stenosis. The maximum width of the pedicle measured using axial CT is 2 mm. E A sagittal magnetic resonance (MR) T2 image shows atlantoaxial dislocation, the dentate process pressing the spinal cord, and a high signal in the spinal cord. F Sagittal CT showed a reduced atlantoaxial median joint and that the cage position between the lateral atlantoaxial joints was suitable (G, H). I Both screws are in proper positions. J Postoperative T2 MR showed that the spinal cord compression was relieved. There was still a high signal in the spinal cord. K, L CT scan showing bone fusion between the bilateral lateral joints at 8 months after surgery