Based on this, I agree with you...22851 rather than 22521
Intervertebral biomechanical device(s) such as synthetic cage(s), threaded bone dowel(s), and/or methylmethacrylate are applied to a vertebral defect or interspace during a separately reportable spinal arthrodesis (fusion) procedure. Intervertebral biomechanical devices, also referred to as interbody fusion devices, are placed within the intervertebral disc space to provide strength and prevent collapse of the disc space. There are a number of different types of devices including cylindrical threaded titanium cages, cylindrical threaded cortical bone dowels obtained from cadavers, vertebral interbody rings or boxes, and methylmethacrylate cement. During a separately reportable procedure, the disc space is prepared, which includes removing the nucleus pulposus, reaming the disc space with removal of subchondral bone, and/or creating drill holes for placing screws or bone dowels. Distraction is applied to spread the vertebral bodies. The selected intervertebral mechanical device is then inserted into the prepared disc space. If a titanium cage, ring, or box device is used, the device is inserted, fixed with screws, and packed with separately reportable bone grafts (allografts and/or autografts). If threaded bone dowels are used, they are inserted into the predrilled holes in the vertebrae. If methylmethacrylate is used, the disc space is coated with gelfoam to prevent leakage into the epidural space. The methylmethacrylate cement is then mixed and injected using a syringe and intercath while the vertebral body distracter is removed