So my Ortho doc performed a L5-S1 spinal fusion, my problem is that he was also a Co Surgeon in the approach, Anterior Retroperitoneal Exposure, and then went on to do the fusion, CPT code 22558. Normaly I would just code this as 22558-62, but that is when the one surgeon does his part, and my Doc does his fusion, How and or what modifier do you use when He is also the co-surgeon in the approach.