Injury of accessory nerve, left side, initial encounter

This code signifies a traumatic injury to the left accessory nerve (cranial nerve XI), which primarily controls the sternocleidomastoid and trapezius muscles. Such an injury can lead to weakness or paralysis of these muscles, affecting shoulder elevation, head rotation, and scapular movement. This specific code is for the initial phase of treatment for the injury.

Apply this code when documentation clearly indicates a new, acute injury to the left accessory nerve, such as from trauma, surgery, or compression. Supporting documentation should include a physician's assessment detailing the mechanism of injury, neurological findings (e.g., muscle weakness, atrophy), and the affected side.

• Ensure laterality is explicitly documented as "left" to support this specific code.
• Confirm the encounter is truly "initial" for treatment of the injury; subsequent encounters will require different seventh characters.
• Distinguish from non-traumatic accessory nerve disorders, which are coded differently (e.g., G52.3- for lesions of the accessory nerve).