Injury of trochlear nerve, left side, subsequent encounter

This code signifies a subsequent encounter for damage to the left trochlear nerve (cranial nerve IV), which controls the superior oblique muscle responsible for downward and outward eye movement. Injury to this nerve typically results in vertical diplopia (double vision) and compensatory head tilt. "Subsequent encounter" indicates the patient is receiving routine care during the healing or recovery phase of the injury.

Apply this code when a patient is being seen for follow-up care, such as medication adjustments, physical therapy, or monitoring of recovery, after an initial injury to the left trochlear nerve. Documentation should clearly state "left trochlear nerve injury" and indicate that this is not the initial treatment phase.

• Ensure documentation specifies "left side" and "subsequent encounter" to support this specific code.
• Distinguish from initial encounters (A) or sequela (S) codes for trochlear nerve injury.
• Consider co-reporting with codes for the underlying cause of the trochlear nerve injury, if applicable and still being treated.