Facet joint injections are quite common. They are used to relieve pain in the spine when other medications don’t work. However, these injections are often not limited to just a single dose. Rather, in the same session, injections are administered to multiple levels.
Billing these multiple injections can be a bit confusing. CPT code 64491 represents an add-on facet joint injection, or the second-level injection.
In this guide, we will explain how you can bill the code correctly. So, let’s start.
CPT Code 64491 – Description
CPT code 64491 is defined as:
“Injection(s), diagnostic or therapeutic agent, paravertebral facet (zygapophyseal) joint (or nerves innervating that joint) with image guidance (fluoroscopy or CT), cervical or thoracic; second level (List separately in addition to code for primary procedure).”
Let’s break this down in simple words. 64491 is basically a pain management billing code. As evident from the definition, it is used for both diagnostic and therapeutic purposes. It is used to bill paravertebral facet joint injections of the second level in the cervical or thoracic region.
Here are the key things to remember about 64491:
- Add-On Status: 64491 cannot be billed on its own. It must always accompany its primary code, i.e., CPT code 64490.
- Scope: The code applies only to the cervical or thoracic spine.
- Imaging Guidance: Like its parent code, 64491 also requires fluoroscopy or CT guidance. However, please note that ultrasound imaging guidance is not a part of this code. If ultrasound is performed, then other more relevant codes should be used.
- Per-Level Reporting: This point confuses billers the most. A facet joint level refers to the joint itself, or the pair of medial branch nerves that supply it, not the individual nerves blocked. One level equals one unit, regardless of how many punctures or how much medication is used.
Additionally, as we have already mentioned, CPT code 64491 is used for both diagnostic and therapeutic purposes; the medicine administered in the injection can vary. In diagnostic cases, anesthetic agents like lidocaine are administered in the joint, while in therapeutic cases, the physician can inject other healing compounds like corticosteroids.
Scenarios Where CPT Code 64491 is Applicable
To make things clearer, let’s look at a couple of real-world scenarios in which CPT code 64491 can be used:
Thoracic Spondylosis
Suppose a patient comes to a clinic. He has an appointment with a pain management specialist. He shares with the physician that he has persistent pain in the upper back. The pain gets worse with movement. The physician orders imaging tests, which reveal spondylotic changes that affect two facet joints in the thoracic region. Conservative treatment, including medication and physical therapy, failed to provide lasting relief.
So, the physician decides to administer a unilateral therapeutic corticosteroid injection under fluoroscopic guidance at two distinct facet levels.
Since two injections were administered at two different levels on the right side of the body, the billing department can bill the first injection with CPT code 64490-RT and the second injection with CPT code 64491-RT.
Axial Pain Worsened by Movement, Cervical Region
Let’s consider another scenario. Suppose that a 48-year-old male patient visits an outpatient pain clinic reporting a 9-month history of localized, non-radiating axial neck pain and stiffness. The pain worsens when he tries to stretch and rotate his neck laterally. This restricts his ability to drive safely, especially when checking blind spots. He does not report radicular numbness, tingling, or motor weakness in the upper extremities.
His previous conservative treatment included 8 weeks of targeted physical therapy, activity modification, and NSAIDs, which resulted in less than 20% temporary relief.
Comprehensive physical exams and a cervical spine MRI show localized axial pain due to left-sided facet joint arthropathy, joint space narrowing, and hypertrophic capsular changes at C4-C5 and C5-C6. Hence, the physician administers a medial branch block (facet joint injection) under fluoroscopic guidance at both cervical levels to confirm the joint involvement before considering radiofrequency ablation.
To bill this dual-level cervical procedure correctly, the billing team will report CPT code 64490-LT for the first-level injection and CPT code 64491-LT for the second-level injection.
Applicable Modifiers for CPT Code 64491
The following are the most frequently used modifiers with CPT code 64491:
| Modifier | Description | Application |
|---|---|---|
| 50 | Bilateral Procedure | Required when injecting both right and left facet joints (or nerves) at the same vertebral level during a single session. |
| KX | Specified Medical Necessity | Used for all facet joint diagnostic injections. Indicates the medical necessity of additional diagnostic injections after the first two. |
| RT/LT | Right/Left Side | Used by ASC facilities for bilateral procedures (reported on separate lines instead of modifier 50). |
Source: CMS
Note: It is essential to note here that for Medicare billing, you can only use modifiers RT and LT if the procedure was performed in an ambulatory surgical center (ASC). Do not use them if the procedure was performed in another setting.
CPT Code 64491 – Billing & Reimbursement Guidelines
The following are some essential points to consider to avoid CPT code 64491 denials:
Always Pair It with the Correct Primary Code
We have already mentioned this above, but let’s emphasize this point. 64491 cannot be used as a standalone code.
It is only valid when used with CPT code 64490. Mismatching the add-on code with the wrong primary code is one of the most common reasons these claims are denied.
Check the Prior Authorization Requirement
This is an important point to note. Since July 1, 2023, Centers for Medicare & Medicaid Services (CMS) requires prior authorization for facet joint injections if performed in hospital outpatient departments.
Take note that this rule is not for physician offices, ambulatory surgical centers, or critical access hospitals.
Provide Detailed Documentation
Comprehensive documentation is what distinguishes a paid claim from a denied one. For CPT code 64491, your medical records should clearly show:
- The specific levels and sides treated (for example, right C4-C5 and right C5-C6), rather than a general reference to “neck injections.”
- The medical necessity for treating a second level, not just the first.
- The image guidance modality used (fluoroscopy or CT) and permanent images stored in the patient record.
- A pain history, including location, severity, and duration of symptoms.
- Evidence of failed conservative treatment before the injection was performed.
- The patient’s response to any prior facet joint interventions, if applicable.
- Physician orders, procedure notes, and a signed attestation form, where applicable.
Final Word
Today, we tried our best to simplify and explain CPT code 64491 to you. However, this guide is quite extensive, so we hope that you took notes on the important points. If you didn’t, here is a quick recap of the essential points that we discussed above:
- Code 64491 is used to bill second-level facet joint injections in the cervical and thoracic regions.
- It should always be used with CPT code 64490, as 64491 is an add-on code.
- Fluoroscopy/CT imaging guidance is included in the code.
- Appropriate modifiers must be appended when necessary.
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