I work for spine surgeons. Many times when a patient requires both anterior and posterior fusions. Rather than subjecting our patient to two surgeries on two different days, we perform the first procedure completely (anterior portion), then flip the patient over, create new incision sites and complete the second stage surgery (posterior portion). I am aware if we performed these procedures on two separate days, all we would need to do is append modifier -58 and we will receive 100% payment on both primary codes (anterior 22558 and posterior 22633). When the procedure is performed the same day, should I be appending modifier -58,59 to get this separate incision code paid at 100%, or is it that being we did the surgeries on the same day, all codes except the highest paying code are subjected to reductions?