Region of Fusion and Number of Vertebrae Fused | Spinal Fusion Coding Series

In Part 1, we learned the diagnoses associated with the need for spinal fusions, and in Part 2 the need to identify if the fusion is an initial or refusion of the vertebrae. In Part 3, we are going to focus on determining the level(s) of fusion, as well as the number of vertebrae fused.


Level(s) of the spinal column and number being fused:

As you can see in the picture below, the human vertebral column consists of 33 vertebrae divided into five regions:

  • Cervical—7
  • Thoracic—12
  • Lumbar—5
  • Sacrum—5 (sometimes 6)
  • Coccyx—4


Photo Courtesy:

Photo Courtesy:

When reviewing the operative note, look for what level(s) are being fused together. A level involves two vertebrae and the space between them (interspace) containing the disc. In ICD-10-PCS, two adjacent vertebrae separated by an interspace (level) is call a vertebral joint.

How to report multiple levels?

When the surgeon documents that a fusion consisted of only two vertebrae, and they are of the same level (such as lumbar) then this is counted as only one level. However, in the same procedure if the surgeon also performs a fusion of another level (such as sacrum), this part of the fusion would also need to be reported.


  • If a patient presents and undergoes a lumbar fusion to include L3-L5, this would be counted as two vertebral joints (L3 to L4 and L4 to L5). Each of these two vertebral joints will be made immobile by the fusion. One way to think of this is like “welding” the two together. Sometimes, we see coders count each level and report as four vertebral joints being fused. But remember in ICD-10-PCS, two adjacent vertebrae separated by an interspace is a vertebral joint.
  • If a patient presents and undergoes a spinal fusion of L4-S1, this would be counted as two vertebral joints (L4 to L5 and L5 to S1), and reported with two ICD-10-PCS codes to include both the lumbar and sacral region of the vertebra. This is because the fusion includes two regions within the vertebrae (lumbar and lumbosacral). As above, this is only two vertebral joints being fused together but of two different regions (lumbar and lumbosacral).
  • If a patient presents and undergoes a spinal fusion of C5-T2, this would be counted as four vertebral joints (C5 to C6, C6 to C7, C7 to T1 and T1-T2), but reported with ICD-10-PCS codes to include both the cervical, cervicothoracic and the thoracic region of the vertebra.

Be on the lookout for Part 4, that will discuss how to identify the spinal column being fused. Download our entire Spinal Fusion series. 

Authored by Kim Boy, RHIT, CDIP, CCS, CCS-P


ICD-10-CM/PCS Coding Clinic, Third Quarter 2019 Pages: 35-36
ICD-10-CM/PCS Coding Clinic, Fourth Quarter 2021 Page: 67
ICD-10-CM/PCS Coding Clinic, Second Quarter 2021 Pages: 23-24
ICD-10-PCS Official Guidelines for Coding and Reporting FY 2023

The information contained in this coding advice is valid at the time of posting. Viewers are encouraged to research subsequent official guidance in the areas associated with the topic as they can change rapidly.

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