Case: An eight-year-old boy presented with acute encephalopathy due to posterior circulation ischemic stroke. He was found to have vertebral artery stenosis secondary to atlantoaxial instability (AAI) due to an os odontoideum. Occipitocervical fusion was performed 4 weeks after stroke. The child improved neurologically and regained independent ambulation. He had indications of an underlying spondyloepiphyseal dysplasia with joint luxation and whole-exome sequencing diagnosed CHST3-related skeletal dysplasia.
Conclusion: As far as we know, this AAI due to an os odontoideum is a previously unreported complication of CHST3-related skeletal dysplasia. Occipitocervical fusion yielded good clinical results with the 1-year follow-up.
Copyright © 2021 by The Journal of Bone and Joint Surgery, Incorporated.