Medial rectus muscle entrapment, left eye

This code describes a condition where the medial rectus muscle of the left eye becomes trapped, typically due to trauma or orbital fracture. This entrapment restricts the eye's movement, particularly adduction (inward gaze), and can lead to diplopia (double vision) and strabismus.

Use this code when documentation clearly indicates entrapment of the medial rectus muscle in the left eye. This often occurs following orbital trauma, such as a blowout fracture, where muscle tissue becomes incarcerated within the fracture site. Supporting documentation should detail the mechanism of injury, clinical findings of restricted eye movement, and imaging results confirming muscle entrapment.

• Ensure laterality is correctly documented and coded; this code specifies the left eye.
• Distinguish entrapment from paresis or paralysis of the medial rectus, which would be coded differently.
• Always code the underlying cause, such as an orbital fracture, in addition to the muscle entrapment.