Classification of odontoid destruction in patients with rheumatoid arthritis using reconstructed computed tomography: reference to vertical migration.

OBJECTIVE: To reveal the factors that determine the natural course of subluxation of occipital-cervical lesions in rheumatoid arthritis (RA). The atlanto-axial region is one of the most common locations for lesions in RA. Some cases progress from reducible atlanto-axial subluxation (AAS) to irreducible vertical migration, while others continue to exhibit reducible AAS. No study has revealed the factors that determine the natural course of subluxation. We focus on the odontoid as a key structure of the progression of occipito-cervical lesions and investigated this region in patients with RA using reconstructive computed tomography (CT) images, and analyzed factors in association with CT findings. METHODS: Fifty-eight patients with RA and 40 age-matched controls, all women, were studied. Associated factors, including C-reactive protein, erythrocyte sedimentation rate, steroid usage, and the severity of local osteoporosis, were analyzed as measurements in association with odontoid destruction. RESULTS: The destruction of odontoid and atlanto-odontoid joint were common in patients with RA. The more destruction observed in the odontoid process, the greater is the degree of progression of vertical migration. Local osteoporosis is a significant factor in odontoid destruction, based on a cortico-cancellous index of 42% in cases of grade III odontoid destruction. CONCLUSION: The odontoid process is a key structure in the progression of occipito-cervical lesions in patients with RA.

Prognosis of patients with upper cervical lesions caused by rheumatoid arthritis: comparison of occipitocervical fusion between c1 laminectomy and nonsurgical management.

STUDY DESIGN: A matched controlled comparative study of patients with upper cervical lesions caused by rheumatoid arthritis was performed at two different hospitals to evaluate occipitocervical fusion associated with C1 laminectomy and nonsurgical treatment. OBJECTIVES: To evaluate the long-term results and advantages of occipitocervical fusion associated with C1 laminectomy, and to compare these results with those of nonsurgical management of patients with myelopathy related to rheumatoid arthritis. SUMMARY OF BACKGROUND DATA: Few studies have reported the prognosis of patients with rheumatoid arthritis managed by occipitocervical fusion associated with C1 laminectomy. METHODS: In this study, 40 patients with rheumatoid arthritis and myelopathy caused by irreducible atlantoaxial dislocation with or without upward migration of the odontoid process were studied. Of these 40 patients, 19 were treated by occipitocervical fusion using a rectangular rod associated with C1 laminectomy at one hospital, whereas 21 matched patients were treated conservatively at another hospital. The patients were observed by the same protocol to assess the radiologic and clinical results, including functional recovery and survival rate. All the patients were followed until their death. RESULTS: The atlantodental interval was reduced immediately after surgery, and this result had been well maintained at the final follow-up assessment. Redlund-Johnell values did not vary significantly throughout the course of the study. As for neural assessment with the Ranawat classification system, improvement was found in 13 (68%) of the 19 patients who underwent surgery. The survival rate was 84% 5 years after surgery, and 37% in the first 10 years. In the patients who did not undergo surgical treatment, atlantodental interval and Redlund- Johnell values were aggravated. These patients showed no neural improvement, and aggravation was found in 16 (76%) of the 21 cases during the follow-up period. All the patients were bedridden within 3 years after the onset of myelopathy. The survival rate was 0% in the first 8 years. CONCLUSIONS: The findings lead to the conclusion that occipitocervical fusion associated with C1 laminectomy for patients with rheumatoid arthritis is useful for decreasing nuchal pain, reducing myelopathy, and improving prognosis.