Ankylosing hyperostosis [Forestier], lumbosacral region

This code represents diffuse idiopathic skeletal hyperostosis (DISH), also known as Forestier's disease, specifically affecting the lumbosacral spine. It is characterized by the calcification and ossification of ligaments and entheses, primarily along the anterior longitudinal ligament, leading to bony bridging between vertebrae in the lower back and sacrum. This condition can result in spinal stiffness and reduced range of motion.

Use this code when documentation confirms a diagnosis of ankylosing hyperostosis (DISH) localized to the lumbosacral region. Supporting documentation should describe characteristic radiographic findings, such as flowing ossification along the anterior longitudinal ligament spanning at least three contiguous vertebrae in the lumbar or sacral spine, often with preservation of disc height and absence of sacroiliac joint fusion.

• Differentiate from ankylosing spondylitis (M45.-) which involves sacroiliac joint fusion and typically affects younger individuals.
• Ensure the documentation specifies the lumbosacral region; other sites of DISH have different codes.
• Look for terms like "Forestier's disease," "DISH," or "diffuse idiopathic skeletal hyperostosis" with anatomical specificity.