Figure 1.

Images of a 49-year-old female patient. (a) T2-weighted magnetic resonance imaging showing extensive syringomyelia. There is no craniovertebral bone or soft tissue abnormality. (b) Sagittal image of computed tomography scan, with the head in flexion position, showing no evidence of atlantoaxial instability when assessed by parameter of atlantodental interval abnormality. (c) Sagittal computed tomography with the cut passing through the facets showing Type B facetal instability. (d) Postoperative computed tomography scan after atlantoaxial fixation. (e) Postoperative computed tomography scan with the cut through the facets showing the implant