Not All Spinal Cages Are Created Equal
When coding cage placement, you must know the type of device used.
By Paula Vandenberg, CPC, CPC-H
The intervertebral fusion cage is a hollow device available in many shapes and sizes. The cage may be made from any of several materials, including titanium or, most commonly, polyetheretherketone (PEEK). The surgeon places bone graft material inside the hollowed mid-portion of the cage. The holes in the cage keep the graft in contact with the bony surface of the vertebrae. This ensures the bone grafting material bonds with the vertebrae, forming a solid fusion.
Understand How Cages Support
The cage helps in several ways: First, it separates and holds two vertebrae apart. This makes the opening around the nerve roots (neural foramen) bigger, relieving pressure on the nerves. As the vertebrae separate, the ligaments tighten up, reducing instability and mechanical pain. The cage replaces the problem disc while holding the two vertebrae in position until fusion occurs.
Some cages require separate instrumentation for stabilization of the fusion. Others are designed with plates attached and/or screws passing directly through them. These are known as “standalone cages” or “cage constructs,” and they are used for anterior approach fusions. Cages falling under this category include: Centinel Spine’s STALIF TT™ and STALIF C™, Medtronic’s Sovereign® and Prevail®, Synthes’s Zero-P, LDR’s ROI-C®, and Globus’s Independence® and Coalition®.
When coding for these standalone cages, you would not add the instrumentation code (22845-22847) for the plate and/or screws because these are considered part of the cage construct. Proper coding is +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), only.
In rare instances, the surgeon may place a standalone cage, and then place a separately reportable plate and/or screws to further stabilize the fusion site. In this case, you may report the instrumentation code (22845–22847) in addition to +22851.
Know Your Devices
Coders must know the type of devices used during a procedure. Reading the operative note only, without researching the type of cage used, may lead to incorrectly reporting an instrumentation code for the plate and screw placement. For example:
At the C4-C5 level, the anterior longitudinal ligament and the anterior annulus were excised. Cartilaginous endplate and nuclear material were removed. The neural foramen were decompressed. Curets were used to prepare the subchondral bone. The C4-C5 disk was markedly degenerative, narrowed and desiccated. Sizing instruments were used. A 6-mm Coalition cage was filled with BMP and Formagraft and was tamped into place. Fixation screws were placed through the anterior plate into the vertebral bodies.
In this example, a Coalition® cage was used and fixation screws were placed through the anterior plate. The anterior plate and screws are part of the cage construct; making it inappropriate to report an instrumentation code separately.
There are more than 25 types of standalone cages—all with different shapes and sizes—and new technology is constantly emerging, making research an ongoing necessity. A manufacturer’s website can be a great resource.
Paula Vandenberg, CPC, CPC-H, is a performance improvement analyst with the Surgical Care Affiliates coding team. She has worked in healthcare for more than 20 years and has been a certified coder for more than 10 years, specializing in spinal/neural coding, with experience in ambulatory surgical center and hospital settings. Vandenberg is a member of the Tucson, Ariz., local chapter.