Atlantoaxial Instability due to Hypoplasia of the Odontoid Process

The authors present a case of a 39-year old man, admitted with neck pain and tingling sensation on his right upper extremity. On radiological investigation, atlantoaxial instability due to odontoid process hypoplasia and mild upper cervical cord compression by abnormal soft tissue were revealed. We performed posterior C1-2 transarticular screw fixation with posterior bone graft and could obtain good postoperative result.