Transoral fusion of odontoid fracture. Case report.

HE odontoid process is a pivot for rotation of the atlas on the axis, but more significantly, it limits posterior motion of the atlas through its articulation with the anterior ring. Anterior dislocation is avoided by the confinement of the thick transverse ligament. The dens represents the body of C-1 which later becomes fused with the axis. Interposed at the base is a cartilaginous disc which ultimately ossifies. Ossification begins at the periphery but may not reach the center until advanced age. In a certain number of persons (s of patients age 30 to 50 years 4) fusion does not occur or is incomplete, allowing dislocation, either spontaneously or as the result of minor trauma. Occasionally the entire process is absent. The incidence of odontoid fractures is not known, since many are not recognized due to immediate death. Amyes and Anderson ~ found 63 among 393 patients having x-ray evidence of fracture or dislocation of the cervical spine. It may not be recognized early because of head injury, or the symptoms of soreness and stiffness of the neck are attributed to cervical sprain or subarachnoid hemorrhage. The signs are seldom outstanding. Only five of the cases of Amyes and Anderson 2 had sufficient cervical cord compression to cause weakness of the arms or legs. The most feared consequence is upper cervical myelopathy due to chronic or repeated dislocation. The selection of treatment still remains an enigma. Alexander, et al., 1 felt that all cases should be operatively fused. Only one fracture united in their four cases not treated surgically. Conversely, Amyes and Anderson 2 found nonunion in only three of their 63 cases. They felt nonunion was more likely if the fracture was in the substance of the dens, whereas those across the base were likely to heal. Reduction and immobilization