Unsp disp fx of second cervcal vert, subs for fx w nonunion

This code describes a situation where a patient has a fracture of the second cervical vertebra (C2) that is displaced, and the specific type of fracture is not documented. The key aspect is that this is a subsequent encounter for the fracture, and it has not healed properly, indicating a nonunion.

This code is appropriate for follow-up visits where a previously diagnosed, unspecified, and displaced C2 fracture is being managed, and imaging or clinical assessment confirms a nonunion. Documentation should clearly state "nonunion" and specify the C2 vertebra, along with the displaced nature of the fracture.

• Ensure documentation explicitly states "nonunion" for the fracture.
• Verify the encounter is for subsequent care, not initial treatment.
• Distinguish from malunion, which indicates healing in an incorrect position, rather than failure to heal.