Ankylosing hyperostosis [Forestier], thoracolumbar region

This code signifies a non-inflammatory spondyloarthropathy characterized by ossification of ligaments and entheses, primarily affecting the anterior longitudinal ligament of the spine. It results in bony bridging between vertebrae, leading to stiffness and reduced range of motion in the thoracolumbar region. This condition is also known as Diffuse Idiopathic Skeletal Hyperostosis (DISH) when affecting multiple spinal segments.

Apply this code when documentation explicitly states ankylosing hyperostosis or Forestier's disease specifically impacting the thoracic and/or lumbar spine. This diagnosis is typically made based on radiographic findings showing flowing ossification along the anterior aspects of at least four contiguous vertebral bodies. Supporting documentation should include imaging reports (X-ray, CT) confirming the characteristic bony changes in the thoracolumbar area.

• Differentiate from ankylosing spondylitis (M45.-), which is an inflammatory condition with different diagnostic criteria and treatment.
• Ensure the documentation specifies the "thoracolumbar region" for accurate code assignment; other sites of involvement would require different codes.
• Do not code based solely on symptoms like back pain; radiographic evidence of hyperostosis is essential for this diagnosis.