Unstbl burst fx first cervcal vert, subs for fx w nonunion

This code describes a severe, unstable fracture of the C1 vertebra (atlas) where the bone has shattered outwards, and the fracture fragments have failed to heal together after an initial treatment. This specific code indicates that the patient is receiving ongoing care for this non-healing fracture, not initial treatment.

Use this code for patients presenting for follow-up care, such as clinic visits, imaging studies, or rehabilitation, related to an unstable burst fracture of the C1 vertebra that has been previously treated but has not achieved union. Documentation should clearly state "nonunion" and specify that the encounter is subsequent to the initial treatment phase.

• Ensure documentation explicitly states "nonunion" of the C1 burst fracture.
• Verify that the encounter is for ongoing care of the nonunion, not for the initial injury or acute treatment.
• Distinguish from codes indicating routine healing or malunion; "nonunion" implies a complete failure of bone healing.