ABSTRACT
Inflammatory conditions at the craniocervical junction (CCJ) consist mainly of rheumatic
diseases and spondyloarthropathies, with rheumatoid arthritis (RA) representing the
predominant example of the former condition. Secondary atlantoaxial subluxation (AAS)
is noted in up to 70% of cases of RA, yet neurologic manifestations are not common.
Atlantoaxial impaction (AAI) however, a less frequent entity, is associated with potentially
grave deficits. All of the seronegative spondyloarthropathies may also have abnormalities
at the CCJ.
Erosive inflammatory changes in the synovium cause damage and subsequent loss of the
adjacent ligament, cartilage, and bone, producing typical radiological features. As
the disease progresses there is worsening instability, yet a corresponding rate of
neurologic compromise is not seen. The life span for patients with RA is approximately
65 years, with mortality being highest in myelopathic patients.
Radiological investigations include plain radiographs, computed tomographic scans,
and magnetic resonance imaging (MRI). The plain films are frequently used for screening,
with the posterior atlantodental interval (PADI) being most predictive of paralysis
from AAS. The Clark's station, the Ranawat criterion, and the Redlund-Johnell criteria
are useful for predicting AAI. MRI currently is most effective for defining CCJ relationships.
Clinical manifestations of CCJ pathology occur because of direct compression by bone/soft
tissue and/or from vertebral or anterior spinal artery compromise. The Ranawat grading
scale is the most universally accepted scale for functional assessment. Prognostic
severity criteria for AAS and AAI are the degree of peripheral joint disease, duration
of RA, seropositivity, male gender, presence of rheumatoid nodules, and use of corticosteroids.
Treatment for RA, either conservative or surgical, is controversial. Intractable neck
pain and neurologic deficits are well-accepted indications for surgery. In asymptomatic
patients the role of surgery is based on a variety of radiologic criteria for instability.
KEYWORDS
Craniocervical junction - inflammatory conditions - rheumatoid arthritis - spondyloarthropathies
