Lesion of lateral popliteal nerve, unspecified lower limb

This code signifies an unspecified injury or dysfunction of the common peroneal nerve (also known as the lateral popliteal nerve) affecting an unstated lower limb. This nerve is responsible for innervating muscles that dorsiflex the foot and evert the ankle, as well as providing sensation to the lateral lower leg and dorsum of the foot. Lesions can result in foot drop, sensory deficits, and gait disturbances.

Apply this code when documentation indicates a lesion of the lateral popliteal nerve, but the specific cause (e.g., compression, trauma, entrapment) is not identified, and the affected lower limb (left or right) is not specified. This code is appropriate for initial encounters or when diagnostic workup is ongoing and a more specific diagnosis is pending.

• Avoid using this code if the laterality (left or right lower limb) is documented; instead, select G57.31 for right or G57.32 for left.
• Do not use this code if the specific etiology of the nerve lesion (e.g., G57.0 for sciatic nerve lesion, G57.1 for meralgia paresthetica) is known.
• Query the provider for clarification on laterality and the specific cause of the lesion to allow for more precise coding when possible.