SI Joint Fusion

Best answers
Surgeon and vendor insist on 27279 (Arthrodesis, sacroiliac joint, percutaneous or minimally invasive (indirect visualization), with image guidance, includes obtaining bone graft when performed, and placement of transfixing device) or 27280 (Arthrodesis, open, sacroiliac joint, including obtaining bone graft, including instrumentation, when performed). The only 'implant' is a Cortical Bone Graft, DBM Sponge which is not obtained from the patient.

I am having a tough time finding info/guidance... Should this be billed as Unlisted Procedure or is one of the listed SI Fusion codes appropriate?

Description of Procedure:
...A lateral view of the sacrum, with a C-arm, was taken to make sure it was out of anteversion. 1015 draps were used to drape off the area to be sterilized. Alcohol and Chloroprep was used on the skin and allowed to dry for the appropriate time. U-draps and a laparotomy drap were used to drap of the sterilized operative field. Bovie was established. All instrumentation was present. Time out was done. An oblique view of the Sacroiliac joint was found lining up the Anterior and posterior sides of the joint 'riverview'. A line was draw on the skin in line with the SI joint. The superior and Inferior aspects of the joint were marked off. One centimeter medial and one centimeter superior into the upper quadrant and one centimeter medial and one centimeter distal 1'bd centimeter longitudinal incisions were made thru the skin and subcutaneous tissue. Bovie was used to cauterize any bleeders. Guide pins were then place superior and inferior at a 90 degree angle to eachother under C-arm quidance thru the incisions made into the superior third and inferior third of the SI joint. Lateral C-arm view was then taken to check the depth of the pins into the SI joint. On lateral view the joint finder was placed over the quide pin to the appropriate position. The working cannula retractor was then placed over the joint finder into the SI joint to the appropriate position and depth. The joint finder and quide pin were removed. The Si joint was drilled to remove cartilage and get into the subchondral bone of the sacrum and the ilium. The broch was then used to prepare the area for insertion of the stabilization grafts. A collagen sponge was then placed into the prepared space and stabilization graft was placed. This was done both superior and inferiorly into the SI joints...

Thanks in advance for any/all replies.