Ankylosing hyperostosis [Forestier], cervical region

This code describes a form of degenerative arthritis characterized by the ossification of ligaments and tendons, specifically affecting the cervical spine. It involves the hardening and calcification of soft tissues, leading to bone formation, primarily along the anterior longitudinal ligament. This condition can result in stiffness, pain, and reduced range of motion in the neck.

Use this code when documentation clearly indicates ankylosing hyperostosis, also known as Forestier's disease, localized to the cervical region. This diagnosis is typically supported by imaging studies (e.g., X-rays, CT scans) showing characteristic flowing ossification along the anterior vertebral bodies of the cervical spine. It applies to patients presenting with symptoms referable to cervical spine involvement.

• Ensure the documentation explicitly states "cervical region" to differentiate from other spinal segments.
• Do not confuse with ankylosing spondylitis (M45.-), which is a distinct inflammatory arthropathy.
• Code any associated neurological manifestations (e.g., myelopathy, radiculopathy) separately as secondary diagnoses.