Nondisp post arch fx 1st cervcal vert, 7thK

This code signifies a fracture of the posterior arch of the first cervical vertebra (atlas) that has not shifted from its anatomical position. The "subsequent encounter" indicates the patient is receiving routine care during the healing phase, but the fracture has failed to unite properly. This nonunion complicates recovery and may require further intervention.

Apply this code when documentation clearly states a nondisplaced posterior arch fracture of C1 is being treated, and the provider notes a nonunion during a follow-up visit. This typically occurs after initial treatment, when imaging confirms the bone fragments have not fused as expected. Supporting documentation includes radiology reports indicating nonunion and physician notes detailing ongoing management for the unhealed fracture.

• Ensure documentation specifies "nondisplaced" and "posterior arch" of C1; other fracture types or locations will require different codes.
• The "K" seventh character is crucial for nonunion in a subsequent encounter; do not use "A" for initial or "D" for routine healing.
• Always sequence this code as the primary diagnosis if the nonunion is the focus of the encounter, followed by any associated conditions or complications.