Injury of accessory nerve, left side, subsequent encounter

This code signifies an injury to the left accessory nerve (cranial nerve XI) that is being treated during a subsequent encounter. The accessory nerve primarily controls the sternocleidomastoid and trapezius muscles, affecting head rotation, shoulder elevation, and scapular retraction. Injury can result in weakness, atrophy, or paralysis of these muscles.

Apply this code when a patient is receiving follow-up care for a previously diagnosed left accessory nerve injury, such as physical therapy, medication management, or monitoring for recovery. Documentation should clearly indicate the left side of the injury and specify that the encounter is not for the initial treatment of the acute injury.

• Ensure documentation specifies "left side" and "subsequent encounter" to support this specific code.
• Distinguish between initial (A), subsequent (D), and sequela (S) encounters based on the patient's treatment phase.
• Consider an external cause code (e.g., W00-Y38) if the cause of the injury is known and relevant.