Ankylosing hyperostosis [Forestier], site unspecified

This code represents a chronic, non-inflammatory condition characterized by the ossification of ligaments and entheses, primarily affecting the spine. It involves the formation of new bone along the anterior longitudinal ligament, leading to bridging osteophytes and potential spinal stiffness.

Use this code when documentation confirms a diagnosis of diffuse idiopathic skeletal hyperostosis (DISH), also known as Forestier's disease, without specific mention of the affected anatomical site. This diagnosis is typically made based on imaging findings (e.g., X-rays, CT scans) showing flowing ossification along the anterior spine.

• Do not use this code if a specific spinal region (e.g., cervical, thoracic, lumbar) is documented; instead, select a more specific M48.1- subcategory.
• Differentiate from ankylosing spondylitis (M45.-), which is an inflammatory condition with different diagnostic criteria and treatment.
• Ensure the documentation clearly states "Forestier's disease" or "diffuse idiopathic skeletal hyperostosis (DISH)" to support this diagnosis.