General Surgery Coding Alert

Question: A patient had bilateral above-the-knee amputations. Two weeks later, he was returned to the operating room because one of the stumps was infected. The wound was opened, and the following services performed: purulent drainage, debridement of necrotic tissue, irrigation of the femur stump, and reapproximation of a portion of the muscle over the end of the stump. The wound was left open, to pack and drain. How should this procedure be coded?

Massachusetts Subscriber  
Answer: The correct code is 27301 (incision and drainage, deep abscess, bursa, or hematoma, thigh or knee region) appended with Modifier 78 (return to the operating room for a related procedure during the postoperative period). This indicates that the procedure was performed within the 90-day global period. A debridement code should not be billed, because it is incidental to the opening of the wound.
 
The procedure also does not qualify as a secondary closure or scar revision of an amputation, which would be coded 27594 (amputation; secondary closure or scar revision). For this code, the wound from the previous amputation should already be healed. For example, 27594 could be used when the scar is revised because there is an insufficient soft-tissue cushion over the remaining bone. The revision is performed to allow the amputee to wear a prosthesis. This is clearly not the situation here, as the return to the operating room is caused by infection that requires drainage.
 
Medicare considers infections to be a related procedure, i.e., complication, although some private carriers may not in which case, use modifier -79 (unrelated procedure or service by the same physician during the postoperative period).