Abnormality of atlanto-axial joint in Down's syndrome has been recognized gradually. We operated upon two cases of os odontoideum with spinal cord compression. A fifteen-year-old girl with significant neurologic compromise was treated by posterior fusion of C1 to C2. But she died of pneumoria five months after surgery. Another case was a two-year-old girl with progressive neurologic deterioration. Posterior fusion of C1 to C2 was performed but fusion was not achieved. We operated again and solid fusion was obtained.
On the basis of our experience, we emphasize that a routine X-ray check up and early diagnosis are important and rigid internal fixation and firm external fixation are also necessary.
