Reappraisal of cervical spine subluxation in Thai patients with rheumatoid arthritis.

Subluxation of the cervical spine is one of a number of devastating complications of rheumatoid arthritis. In spite of this, the features of cervical spine subluxation in Thai patients with rheumatoid arthritis have never previously been studied. We enrolled 134 patients with rheumatoid arthritis who were being followed at the rheumatology clinic, Ramathibodi Hospital, during 1978-2001. Radiological examinations were made in lateral neck flexion, extension and open-mouth views. Symptoms of neck pain and the results of relevant neurological examinations were recorded at the time of imaging. Other data on clinical features and treatments since diagnosis were reviewed retrospectively. The overall prevalence of cervical spine subluxation was 68.7%, which can be categorised into anterior (26.9%), posterior (14.9%), lateral (17.2%), vertical (16.4%) atlantoaxial and subaxial subluxation (28.4%). The percentages of cervical subluxation in patients who had suffered from the disease for 1, 5, 10 or more than 10 years were 77.8%, 64.9%, 70% and 64.7%, respectively. None of the patients had neurological deficits. No correlation between neck pain and cervical spine subluxation was established. The number of patients treated with corticosteroids was significantly higher in the subluxation group than in the non-subluxation group ( p=0.04). However, no difference in duration of treatment and cumulative dosages of steroids was displayed between the two groups. It was concluded that the prevalence of cervical spine subluxation in Thai patients with rheumatoid arthritis is much higher than the average, even in the early phase of the disease. Hence, radiological examination of the cervical spine should be included in the initial evaluation of Thai RA patients. Corticosteroid use was associated with cervical subluxation, regardless of dose and duration of treatment. The possible explanations are that steroids may directly cause ligament laxity, osteoporosis and decreasing muscle mass, which leads to accelerated subluxation, or that steroid treatments are used in more severe cases which have a higher tendency towards cervical subluxation.