抄録
Posterior atlanto-axial subluxation (PAAS) in rheumatoid arthritis is a rare condition, although anterior or vertical subluxations are not uncommon. Seven cases of PAAS were studied clinically and radiographically. Surgical treatment was carried out in 3; 2 for cervical myelopathy and 1 for severe nape and occipital pain. The other 4 cases were treated conservatively with a Philadelphia brace for nape pain.
In the radiographic findings, 3 had a S-shaped curve (upper lordosis and lower kyphosis) and the posterior inclination of the odontoid process was relatively sharp. This means that the articular surface of the odontoid process was receiving a backward load and that the erosion of the process was increased.
When the erosion of the odontoid process is advanced extremely and the odontoid process seems to be absorbed completely, surgical treatment may be indicated because of severe PAAS and cervical myelopathy in such cases. If the erosion of the odontoid process occurs in over two-thirds of the sagittal diameter, it is desirable to take preventive surgery measures against further absorbtion or fracture of the odontoid process.
