DIFFUSE IDIOPATHIC SKELETAL HYPEROSTOSIS

Objective: To describe the axial and appendicular skeleton findings of diffuse idiopathic skeletal hyperostosis. To analyze the role of conv entional radiography, computed tomography (CT) and magnetic resonance imaging (MRI) in the diagnosis of this condition. To discuss the diffe rential diagnosis and diagnostic pitfalls of this disease. Material an d methods: The involvement of vertebral and extravertebral sites inclu ding the pelvis, calcaneum, ulnar olecranon, and patella is frequently found in the literature. The lesions described are the anterior and l ateral ossification of the spine, hyperostosis at sites of tendon and ligament insertion, ligamentous ossification, and periarticular osteop hytes. The criteria for the diagnosis of diffuse idiopathic skeletal h yperostosis involving the spine are: flowing ossification along the an terior and anterolateral aspects of at least four contiguous vertebrae , preserved intervertebral disc height, no bony ankylosis of the poste rior spinal facet joints, and finally no erosion, sclerosis or bony an kylosis of the sacroiliac joints. Results: The disease has about the s ame frequency in men (65%) and women (35%); it is most common in the t horacic spine and occurs less frequently in the lumbar and cervical sp ine. The disease most commonly presents in the sixth and seventh decad es of life and its estimated frequency in the elderly is 5-15%. Signs and symptoms include stiffness and pain in the back, dysphagia due to direct esophageal compression/distorsion, pain related to associated t endinitis, myelopathy related to core compression associated to the os sification of the posterior longitudinal ligament, and pain related to vertebral complications-e.g. fracture/subluxation. Conclusion: While conventional radiography clearly confirms the diagnosis of diffuse idi opathic skeletal hyperostosis, CT and MRI better detect associated fin dings (e.g. ossification of the posterior longitudinal ligament) and c omplications (e.g. spinal cord compressive myelomalacia). (C) 1998 Els evier Science Ireland Ltd. All rights reserved.