RESUMO
OBJECTIVE: We report a case with a long-standing history of the ankylosing spondylitis(AS) who showed multiple cerebellar infarctions with bulbar symptom owing to vertebral artery obstruction, due to anterior and vertical subluxation of atlanto-axial and atlanto-occipital joint. CLINICAL PRESENTARION: An 51-year-old male patient with swallowing difficulty, tongue deviation to the left side and severe nuchal pain and rigidity is presented. INTERVENTION: After removal of posterior portion of foramen magnum, posterior portion of left transverse foramen of axis was decompressed. CONCLUSIONS: Spontaneous anterior atlanto-axial subluxation occurs in patients with AS about 2% of presents with or without signs of spinal cord compression. Vertical subluxation occurs in 3-8% of patient with rheumatoid arthritis but it is an exceedingly rare complication of AS. Close observation and follow-up are needed in patients with AS and if subluxation occurs, good prognosis is anticipated using an early operative treatment.