Spinal fusions are referred to as Arthrodesis in CPT coding and are surgical procedures in which joints are permanently fused using fixation devices to immobilize the joint. For coders, these procedures can be among the most complex to report because accuracy depends on understanding not just the codes, but also the surgical approach, the spinal region involved, and the number of interspaces or vertebral segments treated.
When I first encountered spinal fusion coding during my externship, I will admit I was intimidated. While watching CEO of Healthcare Inspired LLC, during one of our extern roundtables work through a spinal fusion case completely changed my perspective. She carefully dissected the operative report, identifying the site of the spine where the procedure was performed, the surgical approach used (anterior or posterior), and the technique involved (posterolateral, interbody, or combined). She also determined how many interspaces or spinal segments were treated, then checked the NCCI Edits to ensure that the codes selected did not bundle together. Seeing how she walked through each of these steps and tied them to accurate CPT code assignments showed me that spinal fusions, while detailed, are not impossible to master.
That experience taught me that successful coding of spinal fusions requires more than memorizing CPT codes. It requires practice, a working knowledge of spinal anatomy, familiarity with the NCCI Policy Manual, and the ability to apply arthrodesis specific guidelines. Once these elements come together, what once felt overwhelming can become a coding skillset that is both manageable and rewarding.
In this article, I will cover:
- The anatomy of the spine and vertebral column
- Arthrodesis CPT codes and their role in coding
- Key NCCI guidelines (Chapter IV: Musculoskeletal System)
- Modifiers that may be applied in coding Arthrodesis
- 2 case studies showing spinal fusion codes in action
Anatomy of The Spine (Vertebral Column)
The human spine of an adult is composed of a set of 32 vertebrae, divided into five sections:
- Cervical Vertebrae C1-C7
- Thoracic Vertebrae T1-T12
- Lumbar L1-L5
- Sacrum
- Coccyx
A vertebral interspace is defined as the non-bony compartment between two adjacent vertebral bodies that contains the intervertebral disc. This includes the nucleus pulposus, annulus fibrosus, and two cartilaginous endplates.
Arthrodesis
Arthrodesis is a surgery in which the surgeon permanently joins two bones in a joint to one another and can also be referred to as joint fusion. Joints are found within any place in your body where two bones meet. Healthcare providers may suggest this surgery when all other nonsurgical treatments have failed in providing relief from joint pain, stiffness, or trouble moving.
Let’s dissect the word Arthrodesis:
- Fixation of a joint
- Arthro (joint), desis (fusion)
- Surgeons use fixation devices such as pins, wires, rods, etc. to immobilize the joint
- It is usually performed in conjunction with another procedure such as fracture repair
- Code assignments are selected based off approach, site, and the number of segments/ interspaces involved
NCCI Policy Manual Chapter IV: Musculoskeletal System
F. Spine (Vertebral Column)
- Procedures pertaining to spinal arthrodesis, exploration, and instrumentation CPT codes (22532-22865) amongst other spinal procedures include the application of manipulation of the spine as an integral component of the procedure
- Most of the spinal procedures are grouped into families of codes that contain a separate primary procedure code that describes the procedure at a signal vertebral level in the cervical, thoracic, or lumbar region of the spine
- Within these code families there is an add-on-code (AOC) present for each additional level, that does not provide specification of the spinal region
- When a provider performs multiple procedures from one of these families of codes at a contiguous (immediately next to one another) vertebral levels, a provider may only report one primary code from the family of codes for one level and report any additional contiguous levels using AOC(s) within that code family
- The primary code should represent the spinal region of the first procedure is performed
- If the procedure is performed through separate skin incisions at multiple vertebral levels that are noncontiguous, the provider shall report one primary code for each of the noncontiguous region’s example, codes 22532 through 22534 describe arthrodesis performed by a lateral extracavitary technique.
- Example: Code 22532 provides the description for the procedure at a single thoracic vertebral segment, while code 22533 applies to a single lumbar vertebral segment. CPT code 22534 is considered the add-on code, describing the procedure for each additional thoracic or lumbar vertebral segment. If the physician performs this technique on contiguous vertebral segments, such as T12-L1, only one primary procedure code for the first procedure performed is reported. The procedure on the second contiguous vertebral segment is then reported using the add-on code 22534. In contrast, if the physician performs the procedure at T10 and L4 through separate skin incisions the codes reported are 22532 and 22533
- CPT Codes 22600-22614 represent arthrodesis when performed by posterior or posterolateral and lateral transverse technique
- Codes 22630-22632 represent arthrodesis by a posterior interbody technique
- Codes 22633-22634 represent arthrodesis by the combined techniques of posterior or posterolateral with the posterior interbody technique
- Code assignment is reported per level or interspace
- AOC 22614 may be reported with primary CPT codes 22600, 22610, 22612, 22630, or 22633
- AOC 22634 may be reported with primary CPT code 22633
- When a provider performs arthrodesis across multiple interspaces with the same technique within the same spinal region one primary code for the first interspace and an AOC is for each additional interspace is reported
- If the interspaces cross 2 different spinal regions through the same incision, one primary code is reported for the first interspace is reported with an AOC for each additional interspace
- In contrast if the interspaces cross two different spinal regions through separate skin incisions, report a primary code for each skin incision with an AOC for each additional interspace through the same skin incision
- Regardless of multiple techniques being utilized or whether the interspaces are contiguous or noncontiguous, if the provider performs arthrodesis through the same skin incision one primary code is reported for the first interspace followed by AOC(s) for each additional interspace
- Only if the provider performs arthrodesis through separate skin incisions are separate primary codes reported for each skin incision followed by AOC(s) for additional interspace
Arthrodesis and Modifier Guidance
Arthrodesis may be performed alone or alongside another definitive procedure (e.g., osteotomy, fracture care, vertebral corpectomy, or laminectomy). When arthrodesis is combined with another definitive procedure, modifier 51 (Multiple Procedure) is generally appropriate.
However, arthrodesis add-on codes such as 22585, 22614, and 22632 represent additional interspaces and should not be reported with modifier 51. For a single interspace, report the primary arthrodesis code. For each additional interspace, report 22585.
For codes 22548–22558, when two surgeons act as primary surgeons, performing distinct portions of an anterior interbody arthrodesis, each surgeon should append modifier 62 (Co-Surgeon) to report their portion of work. Modifier 62 may also be applied to the additional interspace add-on code 22585, provided both surgeons function as primary surgeons for the entire procedure.
Example: CPT code 22612 describes a posterior or posterolateral lumbar arthrodesis of a single vertebral level. This procedure often involves fixation devices to stabilize the spine. Correct modifier application ensures accurate coding and proper reimbursement.
The table below corresponds specifically to CPT code 22612 and lists common modifiers, along with rules and payment implications:
| Modifier | Description | Rule / Notes |
| 51 | Multiple Procedure | Multiple procedure reduction applies |
| 50 | Bilateral Surgery | No 150% bilateral payment boost |
| 80 | Assistant Surgeon | Assistant payment allowed |
| 62 | Co-Surgeon | Co-surgeon payment allowed |
| 66 | Team Surgery | Team surgeons not permitted |
| 81 | Minimum Assistant Surgeon | Assistant payment allowed |
| 82 | Assistant Surgeon (Qualified Resident Not Available) | Assistant payment allowed |
CPT Codes Commonly Reported Together For Arthrodesis
The following table outlines key CPT codes commonly used in spinal fusion and related procedures. Each entry includes the official code descriptor along with important notes and guidelines for proper application. These codes are frequently reported together because spinal arthrodesis procedures often involve multiple complementary techniques performed at one or more spinal levels. For example, a primary arthrodesis code, such as 22633, identifies the main fusion procedure using a combined posterior or posterolateral technique with posterior interbody fusion at a single lumbar interspace. When additional interspaces are fused during the same surgery, 22614 is added as an add-on code to capture the extra work.
Instrumentation codes like 22842 are commonly reported alongside these primary fusion codes because pedicle fixation or segmental instrumentation is often required to stabilize the spine following arthrodesis. Similarly, codes like 22853 reflect the placement of interbody devices, which are frequently used during interbody fusion to maintain disc space and promote proper spinal alignment. Decompression procedures, such as 63052, may also be performed during fusion to relieve neural compression and are listed as add-on codes to the primary arthrodesis.
Bone grafting is another integral part of fusion procedures. Autograft harvesting (20936) and allograft placement (20930) are typically reported in conjunction with fusion codes, as these biologic materials enhance fusion success. Reporting all relevant codes together ensures that the complexity of the surgery, the multiple interspaces treated, and the supportive procedures required for stabilization and fusion are fully captured. Proper coding of these procedures not only reflects accurate clinical work but also ensures compliance with CPT guidelines and proper reimbursement.
| CPT Code | CPT Official Code Descriptor |
| 22612 | Arthrodesis, posterior or posterolateral technique, single interspace; lumbar (with lateral transverse technique, when performed) Notes: (Do not report 22612 in conjunction with 22630 for the same interspace; use 22633) |
| 22633 | Arthrodesis, combined posterior or posterolateral technique with posterior interbody technique including laminectomy and/or discectomy sufficient to prepare interspace (other than for decompression), single interspace, lumbar Notes: (Do not report with 22612 or 22630 for the same interspace) |
| 22842 | CPT Code Symbols: + Add on code Posterior segmental instrumentation (eg, pedicle fixation, dual rods with multiple hooks and sublaminar wires); 3 to 6 vertebral segments (List separately in addition to code for primary procedure) Notes: Use 22842 in conjunction with: (22100–22102), (22110–22114) (22206–22224) (22310–22327) 22532, 22533, (22548–22558), (22590–22612), 22630, 22633, 22634 (22800–22812) (63001–63030), (63040–63042), (63045–63047), (63050–63056), 63064, 63075, 63077, 63081, 63085, 63087, 63090, 63101, 63102, (63170–63290), (63300–63307) |
| 22614 | CPT Code Symbols: +Add on code Arthrodesis, posterior or posterolateral technique, single interspace; each additional interspace (List separately in addition to code for primary procedure) Notes: Use 22614 in conjunction with 22600, 22610, 22612, 22630, or 22633 when performed for arthrodesis at a different interspace. When performing a posterior or posterolateral technique for fusion/arthrodesis at an additional interspace, use 22614. When performing a posterior interbody fusion arthrodesis at an additional interspace, use 22632. When performing a combined posterior or posterolateral technique with posterior interbody arthrodesis at an additional interspace, use 22634. For facet joint fusion, see 0219T–0222T. For placement of a posterior intrafacet implant, see 0219T–0222T. |
| 63052 | CPT Code Symbols: +Add on code # Resequenced Code Laminectomy, facetectomy, or foraminotomy (unilateral or bilateral with decompression of spinal cord, cauda equina and/or nerve root[s] [eg, spinal or lateral recess stenosis]), during posterior interbody arthrodesis, lumbar; single vertebral segment (List separately in addition to code for primary procedure) |
| 22853 | CPT Code Symbols : +Add on code # Resequenced Code Insertion of interbody biomechanical device(s) (eg, synthetic cage, mesh) with integral anterior instrumentation for device anchoring (eg, screws, flanges), when performed, to intervertebral disc space in conjunction with interbody arthrodesis, each interspace (List separately in addition to code for primary procedure) Notes: Use 22853 in conjunction with the following codes: (22100–22102), (22110–22114), (22206–22207), (22210–22214), (22220–22224), (22310–22327), 22532, 22533, (22548–22558), (22590–22612), 22630, 22633, 22634, (22800–22812), (63001–63030), (63040–63042), (63045–63047), (63050–63056), 63064, 63075, 63077, 63081, 63085, 63087, 63090, 63101, 63102, (63170–63290), (63300–63307) Report 22853 for each treated intervertebral disc space. |
| 20936 | CPT Code Symbols: +Add on code Autograft for spine surgery only (includes harvesting the graft); local (eg, ribs, spinous process, or laminar fragments) obtained from same incision (List separately in addition to code for primary procedure) Notes: Use 20936 in conjunction with the following codes: 22319, 22532, 22533, (22548–22558), (22590–22612), 22630, 22633, 22634, (22800–22812). |
| 20930 | CPT Code Symbols: +Add on code Allograft, morselized, or placement of osteopromotive material, for spine surgery only (List separately in addition to code for primary procedure) Notes: Use 20930 in conjunction with the following codes: 22319, 22532, 22533, (22548–22558), (22590–22612), 22630, 22633, 22634, (22800–22812). |
Now that we’ve reviewed the code set and an example of modifier guidelines for spinal arthrodesis, let’s see how they come together in practice. Proper reporting of spinal fusion procedures requires not only knowledge of the operative steps, but also an understanding of how CPT codes are structured within families of primary and add-on codes.
The following case studies illustrate different clinical scenarios where spinal fusion is performed. Each case demonstrates how physician documentation drives code assignment, how noncontiguous versus multilevel procedures are distinguished, and how additional services such as instrumentation, decompression, or grafting are separately reported. By analyzing operative notes step by step, we can see exactly how medical necessity and surgical technique translate into precise CPT coding.
📋 Case Study 1:
Preoperative Diagnosis:
Cervical spondylolisthesis at C5–C6 (M43.12)
Postoperative Diagnosis:
Same as preoperative
Procedure Performed:
Anterior cervical arthrodesis with discectomy, osteophytectomy, and decompression at C5–C6
Operative Description:
The patient presented with cervical spondylolisthesis at C5–C6. Through an anterior cervical approach, the C5–C6 disc space was exposed. The intervertebral disc was removed, and the disc space was prepared. Osteophytes compressing the neural elements were excised, and decompression of the spinal cord and nerve roots was performed. Arthrodesis was completed at the C5–C6 interspace. The wound was irrigated and closed in layers.
CPT Code Assignment:
- 22551 – Arthrodesis, anterior interbody, including disc space preparation, discectomy, osteophytectomy, and decompression of spinal cord and/or nerve roots; cervical below C2
📋 Case Study 2:
Preoperative Diagnosis:
- Pseudarthrosis after fusion, lumbar region (M96.0)
- Other low back pain (M54.59)
- Status post lumbar fusion (Z98.1)
Postoperative Diagnosis:
Same as preoperative
Procedure Performed:
Revision posterior lumbar fusion at L4–L5 and L5–S1 with pedicle screw instrumentation and bone grafting.
Operative Description:
The patient, with a history of prior lumbar fusion, presented with pseudarthrosis and chronic back pain. A posterior approach was made to the lumbar spine. Fusion was revised at L4–L5 and extended to L5–S1. Pedicle screws and rods were placed spanning L4 through S1 to provide stabilization. The fusion bed was decorticated, and local autograft harvested from the surgical site was combined with morselized allograft. This graft mixture was packed into the lateral gutters to promote fusion. Hemostasis was achieved, and the wound was closed in layers.
CPT® Code Assignment:
- 22612 – Arthrodesis, posterior or posterolateral technique, lumbar, single interspace (L4–L5)
- 22614 – Arthrodesis, posterior or posterolateral technique, lumbar, each additional interspace (L5–S1)
- 22842 – Posterior segmental instrumentation, 3–6 vertebral segments (L4–S1)
- 20930 – Allograft, morselized, for spine surgery only
- 20936 – Autograft for spine surgery only, local, obtained from same incision
Closing Thoughts
Coding spinal fusions, or arthrodesis, is one of the most detailed and technical areas in musculoskeletal coding. Throughout this article, we explored the fundamentals of the spine and vertebral column, the definition and purpose of arthrodesis, and how CPT guidelines define procedures based on the site of the spine, surgical approach, and technique. We also reviewed the NCCI Policy Manual, which provides essential direction for avoiding bundling errors, and examined the role of modifiers in ensuring accurate reporting and proper reimbursement.
The CPT code families for arthrodesis were broken down to show how primary and add-on codes work together, including the use of instrumentation, grafting, decompression, and interbody devices. Two case studies then demonstrated how these rules apply in real practice: the first illustrated coding for a noncontiguous arthrodesis without instrumentation, while the second highlighted a more complex lumbar fusion that included instrumentation, grafting, and decompression. Together, they underscore how documentation, anatomy, and coding guidelines intersect in the decision-making process.
In the end, mastering spinal fusion coding requires more than memorization. It takes practice, a strong grasp of anatomy, close reading of operative reports, and careful application of CPT rules and NCCI guidance. With attention to detail and consistent practice, even complex spinal fusions can be coded with confidence, ensuring both compliance and accurate reflection of the care provided.
Works Cited
- AAPC. Codify by AAPC. AAPC, https://www.aapc.com/codify.
- Medutrain. Coding for Musculoskeletal Procedures. Medutrain, https://medutrain.thinkific.com/courses/take/coding-for-musculoskeletal/lessons/48611126-musculoskeletal-coding.
- Centers for Medicare & Medicaid Services. Medicare National Correct Coding Initiative Policy Manual for Medicare Services. Chapter IV: Surgery: Musculoskeletal System, https://www.cms.gov/files/document/medicare-ncci-policy-manual-2024-chapter-4.pdf.
- American Medical Association. CPT® 2025 Professional Edition. American Medical Association, https://www.ama-assn.org/practice-management/cpt. Accessed 30 Aug. 2025.
- Mayo Clinic. Spinal Fusion. Mayo Clinic, https://www.mayoclinic.org/tests-procedures/spinal-fusion/about/pac-20384523.
- “Billing and Coding: Cervical Fusion (A59674).” Medicare Coverage Database, Centers for Medicare & Medicaid Services, 11 Aug. 2024, U.S. Department of Health and Human Services, https://www.cms.gov/medicare-coverage-database/view/article.aspx?articleid=59674&ver=15.
- Centers for Medicare & Medicaid Services. Billing and Coding: Lumbar Spinal Fusion, Article ID A56396, Medicare Coverage Database, updated January 1, 2023, https://www.cms.gov/medicare-coverage-database/view/article.aspx?articleid=56396&ver=11&.