Injury of accessory nerve, unspecified side, sequela

This code signifies a long-term or residual effect resulting from a past injury to the accessory nerve (cranial nerve XI). This nerve primarily controls the sternocleidomastoid and trapezius muscles, affecting shoulder movement and head rotation. A sequela indicates that the acute injury has resolved, but permanent damage or dysfunction persists.

Use this code when documentation clearly indicates a chronic or late effect of a previous accessory nerve injury, such as persistent weakness, atrophy, or limited range of motion in the shoulder or neck. The "S" at the end of the code indicates that this is a sequela, and it should be used for conditions that are the late effects of the initial injury. Documentation should specify the injury as "unspecified side" if the laterality is not known or recorded.

• Always assign a sequela code (ending in "S") when the patient is presenting for treatment of a residual condition after the acute phase of the injury has passed.
• Do not use this code for acute injuries; instead, use the appropriate acute injury code from the S04 category without the "S" extension.
• Ensure documentation specifies "unspecified side" if laterality is not documented. If laterality is known, use the more specific codes (S04.71XS for right, S04.72XS for left).