|Case of the Week - Patient Summary 5640|
Peer Reviewed and Certified -
|Demographics: 75 y.o. woman|
|History & Chief complaint:|
| 75 yo female with long history of rheumatoid arthritis who is being evaluated for operative planning requiring general anesthesia. Needs flexion/extension views of the cervical spine to rule out instability. |
|Physical exam: Not Available|
|Summary of Findings:|
|There is an increased atlanto-axial distance demonstrated with flexion compared to extension. Additionally, degenerative changes of the lower cervical spine are present.|
Traumatic transverse ligamentous disruption
| Atlanto-axial Subluxation in Rheumatoid Arthritis |
|Rheumatoid arthritis is a chronic progressive, systemic inflammatory disease primarily affecting synovial joints, and can also be a cause of severe neurologic disability. The cervical spine is affected in about 50% of patients with rheumatoid arthritis. Spinal problems with rheumatoid arthritis are primarily related to loss of articular cartilage, ligamentous destruction, and bone erosion. These changes lead to cervical instability that may be demonstrated on radiographs as (1) atlantoaxial subluxation, (2) cranial settling, and (3) subaxial cervical subluxation, in that order.
Atlantoaxial subluxation is caused by both ligamentous and bony changes. Loss of integrity in the transverse ligament is the major pathologic change and is often associated with bony erosion at the insertion site of the ligament on the dens. Also, joint capsule destruction and granulation formation occur between the C1-C2 lateral masses. These pathologic changes lead to anteroposterior and, to a lesser degree, rotatory luxation.
As demonstrated by dynamic (flexion/extension) cervical spine radiographs, the atlanto-odontoid distance provides a measurement of atlantoaxial instability. Intervals greater than 3 mm are abnormal, and those greater than 7 to 8 mm are associated with cervical myelopathy. Indications for surgery to correct rheumatoid atlantoaxial instability include neurologic deterioration and intractable pain. In patients with severe atlantoaxial instability and stable or no neurologic deficits, the indications for surgery are less clear though an atlanto-odontoid interval of 8 mm or greater is commonly used.