Coding Mastery

Segmental vs. Non-Segmental Spinal Instrumentation (CPT codes 22840-22848)

When it comes to coding insertion of spinal instrumentation, there is no shortage of code choices available in CPT. As you begin reviewing the code descriptions for CPT codes 22840-22848, you will notice that you need to gather a few details before you can select your instrumentation code.

First, all of these codes are add on codes that include the language list separately in addition to primary procedure in their code descriptors. This means that you can never report one of these codes by itself. You must first report a primary procedure such as a fusion (CPT codes 22590-22612, 22630, 22633, 22634) or a decompression/discectomy (CPT codes 63001-63030, 63040-63042, 63045-63047, 63050-63056, 63064, 63075, 63077). The CPT manual or your electronic coding software will contain a complete list of valid primary CPT codes with which you can report insertion of spinal instrumentation. Getting your primary procedure coded correctly is step number one.

Second, you need to know the total number of vertebral segments for the instrumentation procedure. CPT defines a vertebral segment as “a single complete vertebral bone with its associated articular processes and laminae.” So when determining the total number of vertebral segments for instrumentation, we are counting bones. For example, screws and rods from L1-L3 = 3 segments. As we begin to look at some of the CPT code descriptions for spinal instrumentation, we see why accurately counting the total number of segments is important. CPT 22842 is for posterior instrumentation of 3 to 6 segments while CPT 22846 is for anterior instrumentation of 4 to 7 segments just to give a couple examples.

Third, you need to determine the surgical approach for insertion of instrumentation – anterior or posterior. CPT codes 22840-22844 and 22848 are all intended to report posterior approaches to placing spinal instrumentation based on their code descriptions or the anatomy where instrumentation is placed. On the other hand, CPT codes 22845-22847 are for an anterior approach. While it is always great if a surgeon specifically documents whether instrumentation is placed from an anterior or posterior approach, more often than not, we get clues in the operative report that require us to abstract this detail. For example, if the surgeon makes a midline incision and then describes viewing the spinous processes, the laminae, or the facets, you can confirm he is using a posterior approach based on the anatomy immediately visualized since all of these structures are on the back of the vertebrae. In another example, if the surgeon describes making a cervical incision and releases the strap muscles (a group of muscles in the front of the neck), you can confirm she is using an anterior approach. Knowing your anatomy and terminology will be the key to coding any spinal surgical procedures including insertion of spinal instrumentation.

Finally, when we look at the codes for posterior instrumentation (specifically CPT codes 22840 and 22842-22844), we see one final distinguishing detail to help us select the appropriate CPT code: segmental vs. non-segmental instrumentation. What exactly does that mean? Non-segmental instrumentation is instrumentation placed across a single interspace (e.g., rods from L3-L4) or instrumentation that spans multiple segments but where instrumentation is inserted only into the vertebrae at the ends. For example, if a surgeon inserts pedicle screws at L1 and L3 and then places rods that span from L1 to L3, but there is no instrumentation inserted in L2 in between the ends of the instrumented segments that is also non-segmental instrumentation. Segmental instrumentation is just the opposite. The surgeon still places instrumentation in the vertebrae at the ends, but also places instrumentation into at least one intervening segment in between the vertebrae at the ends. For example, if a surgeon places pedicle screws at L1, L3, and L5 and then inserts rods that span from L1 to L5, he has inserted instrumentation in the vertebrae at the ends (L1 and L5) and in at least one intervening segment (L3 in this example) – that is considered segmental instrumentation. The same would be true if the instrumentation had been inserted in L2 or L4 instead of L3 as the intervening segment or if it had been in all three of those vertebrae or some subset of those three vertebrae. As long as there is instrumentation in at least one intervening segment, you are looking at segmental instrumentation.

Okay let’s look at a couple of final examples to help solidify coding of spinal instrumentation:

Example # 1: After sterile prep and drape, a lumbar midline incision was made. Upon retraction of the soft tissues, we immediately identified the spinous processes of L1, L2, L3, and L4 in the surgical field. We then performed a laminectomy w/ foraminotomy at each of these segments from L1-L4 to address the foraminal stenosis (63047 x1 and 63048 x3). We had to remove significant bone at L2 and L3 due to the degree of hypertrophy and stenosis so the decision was made to place instrumentation. We inserted pedicle screws bilaterally at L1, L3, and L4 and then locked our rods into place. We elected not to place any pedicle screws at L2 because of the significant bone loss on the left. We irrigated and ensured no bleeding or CSF leak was present and then closed in layers.

Answer Example #1: The bolded and italicized portions of the note above are keys to accurate code selection. First, we see that after making the lumbar incision, the surgeon identifies the spinous processes of the vertebrae in the field. This lets us know that this was a posterior approach since the spinous processes are the knobby areas of bone on the back of each vertebra. Next, we see the primary procedure of the decompression (I included codes above even though that is not the focus of this article simply to demonstrate we have a valid primary CPT code for our instrumentation code that will follow). The surgeon then inserts instrumentation which spans from L1-L4 (L1 and L4 are the vertebrae at the ends of the instrumentation). He also inserts pedicle screws at L3 and then locks rods in place. Even though he ultimately decides not to place any screws at L2, he still places instrumentation (pedicle screws) in at least one intervening segment by placing them in L3. So this is segmental instrumentation. Finally, we need to count our total segments spanned by the instrumentation which is 4 segments in total (L1, L2, L3, and L4). So our final code based on 4 segments, a posterior approach, and segmental instrumentation is CPT 22842.

Example # 2: After sterile prep and drape, a midline incision was made on the back of the neck. We carefully avoided neurovascular structures and then approached the facets from C3-C5. The facets and laminae of each vertebra from C3-C5 were then carefully decorticated and prepared for fusion. We then took morselized allograft (20930) and mixed with some of the decorticated bone from the field (20936) we placed an onlay graft from C3-C5 (22600 x1 and 22614 x1). We decided to augment the fusion with instrumentation for further support. We placed pedicle screws at C3 and C5 and then locked our rods into place. We were happy with the stability of our construct. Hemostasis was ensured and CSF leak was ruled out. We then closed in layers.

Answer Example # 2: Once again, the bolded portions of the note are key to selecting our instrumentation code. First, we see that the surgeon makes an incision “on the back of the neck.” That tells us right there this is a posterior approach, but just in case a coder passed over that detail, he then describes visualizing the facets which are the joints between two vertebrae and are located on the back of the vertebrae. This further confirms this is again a posterior approach. The surgeon then completes the posterolateral fusion (again, I included some suggested codes there for fusion so we can validate we have an appropriate primary CPT for our instrumentation code). Next, they place pedicle screws at C3 and C5 and lock rods in place. C3 and C5 are the vertebrae at the ends of the instrumentation. While the instrumentation spans across two interspaces (C3-C4 and C4-C5), there is no instrumentation inserted in the intervening segment of C4. Therefore, this is non-segmental instrumentation. So with a posterior approach and non-segmental instrumentation, this documentation supports CPT 22840. For clarity, even though 3 vertebral segments are spanned by the instrumentation, we cannot code CPT 22842 (3 to 6 vertebral segments) because this is not segmental instrumentation.

Spinal surgery can be a ton of fun to code once you are comfortable with the codes and guidelines for this challenging specialty. Do you have any additional spinal instrumentation scenarios you need help navigating? Drop your brief note without patient information in the comments below, and I will be happy to work through the coding with you. This also provides an opportunity to share responses with others who may have the same questions.

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