TM 100 trabecular metal implant by Zimmer

One of my surgeons just started using this in his ACDF cases. I am unsure how to code this. It sounds like it replaces allograft bone, so I was thinking to just code it 20931 but then I started wondering if it was considered more like an intervertebral device and should be 22851. I put a call into Zimmer but I wanted someone else's opinion besides the vendor.
Thanks in advance!
Bonnie Moeller
Ft Wayne Neurosurgery/PMR/ASC

re: TM 100 trabecular metal implant by Zimmer

22851 Application of intervertebral biomechanical device(s) (eg, synthetic cage(s), methylmethacrylate) to vertebral defect or interspace (List separately in addition to code for primary procedure)