Neurosurgery Coding Alert

If you approach arthrodesis claims with dread, it's time to get rid of your fears. Our experts reveal the shortcuts and insider knowledge you-ll need to select the appropriate arthrodesis codes with confidence, every time.

The first question you should ask yourself when you pick up a spinal fusion claim is, "Which arthrodesis technique did the surgeon use?"

CPT groups arthrodesis procedures into four primary code categories, each of which describes a particular method for achieving spinal fusion:

1. Lateral extracavitary approach technique (22532-22534)

2. Anterior or anterolateral approach technique (22548)

3. Interbody technique (22554-22585 anterior approach and 22630-22632 posterior approach)

4. Posterior, posterolateral or transverse process technique (22590-22614).

What to watch for: Most claims you will see will describe either the posterolateral/posterior or interbody technique.

Posterolateral or posterior fusion places the bone graft between the transverse processes in the back of the spine, within the facet joints, or along the lamina, says Gregory Przybylski, MD, director of neurosurgery at the New Jersey Neuroscience Institute, JFK Medical Center in Edison.

The surgeon may then fix the vertebrae in place with screws through the pedicles or facets and/or wire through the facets or spinous processes of each vertebra, which themselves may attach to a metal rod on each side of the vertebrae.

Remember: The fixation is separately billable from the arthrodesis.

Interbody fusion, in contrast, places the bone graft between the vertebrae in the area usually occupied by the intervertebral disc. In preparation for the spinal fusion, the surgeon will remove the disc nearly entirely. The surgeon may additionally place a prosthetic device (materials include plastic, carbon fiber or titanium) between the vertebrae to maintain spine alignment and disc height. The actual fusion then occurs between the bony endplates of the vertebrae.

Once again, Przybylski says, the interbody prosthetic device is also separately billable from the arthrodesis and other instrumentation.

Your surgeon's documentation should be explicit on the technique and approach he used. Be aware that in some cases the surgeon may use a "combined" technique (see "Watch for 360-Degree Fusion," page 51). In all cases, if the surgeon's notes aren't explicit, ask for clarification and amended documentation. (Remember: If you can't interpret the operative note, an auditor or claims reviewer will likely not be able to either, if necessary.)

Next, if the surgeon performs the arthrodesis using an interbody technique (with the bone graft taking the place of the intervertebral disc), you must further determine the approach the surgeon used.

Unlike the other techniques listed above -- in which the approach is integral to the technique -- the surgeon can perform interbody fusion using either an anterior (from the front) or a posterior (from the back) approach, says Nancy Reading, RN, BS, CPC, director of educational services for the American Academy of Professional Coders.

Tip: When reading the operative note, pay attention to which way the patient is facing on the OR table, Reading says. "A supine position says anterior approach, while prone usually means a posterior approach."

For an anterior interbody fusion, you can narrow your code range to 22554-22585.

For a posterior interbody fusion, select from the 22630-22632 range.

Finally, you should search the documentation to find exactly which vertebrae the surgeon targeted for fusion.

Important: Arthrodesis occurs between vertebrae for lateral extracavitary, anterior or anterolateral and posterior interbody approaches. Therefore, if the surgeon fuses T8 to T9, arthrodesis occurs at one level, Reading says. By the same token, a fusion from L1 to L3 would involve two levels (L1-L2 and L2-L3).

"The unit of service here is the interspace," Reading says. "And, as such, the interspace has a vertebra above and below.  You determine the number or units of service for procedures that occur at an interspace by taking the number of vertebrae and subtracting 1."

Coder, beware: Arthrodeses done via a posterior or posterolateral approach (22600-22614) are performed at the level of the vertebral segment," Reading says. "These are counted one-for-one as units of work."

CPT arranges arthrodesis codes into spinal regions, using "initial" and "each additional" codes, such as:

- 22554 -- Arthrodesis, anterior interbody technique, including minimal discectomy to prepare interspace (other than for decompression); cervical below C2

- 22556 -- - thoracic

- 22558 -- - lumbar

- +22585 -- - each additional interspace (list separately in addition to code for primary procedure).

You should report only one "primary level" code per session, even if the surgeon crosses spinal regions (for instance, from thoracic to lumbar). For all levels beyond the first, you would use the appropriate add-on, "each additional" code (see "Choose a Single Primary Level for Cross-Region Arthrodesis," page 52, for more information).

In some cases, the surgeon may perform PLIF (posterior lumbar interbody fusion, 22630) or ALIF (anterior lumbar interbody fusion, 22558) along with posterolateral fusion (22612) to stabilize the spine from both the front and back. You may hear surgeons refer to either combination as a "360 fusion."

If your surgeon performs and documents a 360 fusion, you may report both 22630 (or 22558), as appropriate, along with 22612, Przybylski says.

Arthrodesis may include related procedures such as laminectomy and/or discectomy, as indicated in the individual code descriptors, Reading says. You should not report included procedures separately with arthrodesis.

Exception: For various reasons, the surgeon may perform a "greater than usual" decompression during arthrodesis, Przybylski says. In such cases, separate coding for the decompression may be justified.

For example: The surgeon performs laminectomy and decompression that goes beyond that involved in the bony removal required to carry out the PLIF. Therefore, you may report 63047 (Laminectomy, facetectomy and foraminotomy [unilateral or bilateral with decompression of spinal cord, cauda equina and/or nerve root(s) (e.g., spinal or lateral recess stenosis)], single vertebral segment; lumbar) in addition to the PLIF (22630, Arthrodesis, posterior interbody technique, including laminectomy and/or discectomy to prepare interspace [other than for decompression], single interspace; lumbar; and +22632, ... each additional interspace [list separately in addition to code for primary procedure], as necessary).

Append modifier 59 (Distinct procedural service) to the laminectomy (63047) to specify that the decompression is separate from the arthrodesis.

By linking a different diagnosis to each procedure (for instance, lumbar stenosis [724.02] with 63047, and lumbar spondylolisthesis [756.12] with 22630), you can further clarify that the procedures are unrelated.

In short: "Codes 22554-22585 and 22630-22632 describe scrapping away just enough of the disc to make room for graft material," Reading says. When the surgeon performs a complete discectomy for decompression of a spinal nerve, you should code the decompression separately with modifier 59.

"The dictation must clearly identify the separate nature of the two procedures and the medical necessity and performance of decompression," Reading says.

Learn more: See Reader Question "Discectomy May Be Separate With Arthrodesis" on page 55 for an example of "more than minimal" discectomy with arthrodesis.

Don't miss legitimate coding opportunities: Although arthrodesis codes describe the techniques and procedures necessary to prepare the joint for spinal fusion and placement of the bone graft, they do not include harvest of spinal bone grafts and/or spinal instrumentation. You may report both spinal bone graft harvest (20930-20938) and/or instrumentation procedures (22840-22851) separately with arthrodesis (22532-22632).

Make it easy on yourself: With the answers at hand for each of the above three questions, you can find the arthrodesis codes you need in a snap by referring to the "Quick Code Selection Chart" on page 53.

To sharpen your arthrodesis coding skills, follow these examples. Be sure to keep in mind the points we have raised about proper arthrodesis coding (choose one primary level per session, pay attention to which procedures you should include and report separately).

Example 1: Via anterior approach, the surgeon uses minimal discectomy to prepare interspaces C4-C7 for interbody fusion.

We begin by answering the three crucial questions:

1. How did the surgeon do it? (interbody technique)

2. If interbody, what's the approach? (anterior)

3. Which, and how many, vertebrae are involved? (three cervical levels, C4-C5, C5-C6 and C6-C7)

Our code choices:

- 22554 for the initial level (C4-C5). This code describes both the chosen approach (anterior) and technique (interbody).

- 22585 x 2 for each of the additional two levels.

You would not code separately for the minimal discectomy. If, however, the surgeon performed a decompression of the spinal cord and/or nerve root(s), you could report the decompression, Przybylski says.

Example 2: The surgeon prepares interspace L2-L3 for fusion by combined posterolateral and lateral transverse technique.

Our code choice:

- 22612 -- Arthrodesis, posterior or posterolateral technique, single level; lumbar (with or without lateral transverse technique).

You should not code separately for the combined approach because 22612 includes posterolateral technique either alone or in combination with the lateral transverse technique. Although this surgery involves two vertebral segments (L2 and L3), it describes a single vertebral level (interspace).

Example 3: The surgeon performs PLIF for stenosis (724.02, Spinal stenosis; lumbar region) at interspaces L2-L3 and L3-L4. He harvests bone from the iliac crest, via a separate incision, to prepare and place a morselized graft at each interspace. He then fixes pedicle screws at two points to stabilize the spine further.

Our code choice:

- 22630 (Arthrodesis, posterior interbody technique, including laminectomy and/or discectomy to prepare interspace [other than for decompression], single interspace; lumbar) for the first interspace (L2-L3).

- +22632 (- each additional interspace [list separately in addition to code for primary procedure]) for the additional interspace (L3-L4).

Here again, the surgeon chooses an interbody technique, this time with a posterior approach, which you would report as follows:

- 20937 (Autograft for spine surgery only [includes harvesting the graft]; morselized [through separate skin or fascial incision] [list separately in addition to code for primary procedure]) for harvesting, preparing and placing the morselized graft

- +22840 (Posterior non-segmental instrumentation [e.g., Harrington rod technique, pedicle fixation across one interspace, atlantoaxial transarticular screw fixation, sublaminar wiring at C1, facet screw fixation]) for the pedicle screws.