To the Editor.
—Ankylosing spondylitis (AS) is a chronic inflammatory arthritis with a predilection for involvement of cartilagenous joints of the axial skeleton. Pain may be localized to the lumbar region or sacroiliac joints, with stiffness pronounced after prolonged inactivity in the morning, and relieved by movement or heat. In addition, this disease is characterized by the absence of both rheumatoid factor and subcutaneous nodules, and the presence of extraskeletal manifestations such as acute anterior iridocyclitis, atrioventricular block, pulmonary fibrocystic disease in the upper lobes, spinal articular involvement, and nerve root involvement. Thomas et al1 have demonstrated that neurologic profiles in AS can fall into five major categories as follows: multiple sclerosis, the cauda equina syndrome, focal epilepsy, vertebrobasilar insufficiency, and peripheral nerve lesions. With regard to clinical management, relief of articular pain and discomfort and long-range planning for correction or prevention of deformity are of first importance. Actually,