CPT 64490–64492: Cervical/Thoracic Medial Branch Block Billing Guide

A medial branch block (MBB) is a procedure used to diagnose or treat pain originating from the facet joints.

In this case:

Cervical region → neck

Thoracic region → upper/mid-back

• Identify facet joint pain
• Provide temporary pain relief
• Determine eligibility for radiofrequency ablation (RFA)

Medial branch nerves carry pain signals from facet joints to the brain.

During the procedure:

• A local anesthetic (with or without steroid) is injected
• The nerve is temporarily blocked
• Pain relief confirms facet joint involvement

If successful, the patient may qualify for radiofrequency ablation (RFA).

Understanding these codes is critical for proper billing.

• 64491 and 64492 are add-on codes
• They must always be billed with 64490

A level refers to a facet joint segment, not the number of injections.

Example:

C3–C4 = 1 level

C4–C5 = another level

C5–C6 = another level

Coding Examples:

1 level → 64490

2 levels → 64490 + 64491

3 levels → 64490 + 64491 + 64492

Multiple injections at the same level still count as one level only.

Coding CPT 64490–64492 correctly requires a step-by-step approach. Small errors in level selection or modifiers can lead to denials or underpayment.

Start by carefully reading the physician’s documentation. Identify:

• The exact levels treated
• The region (cervical or thoracic)
• Whether the procedure was unilateral or bilateral

Accurate coding always begins with clear documentation.

Determine how many facet joint levels were treated.

1 level → 64490

2 levels → 64490 + 64491

3 levels → 64490 + 64491 + 64492

Remember, multiple injections at the same level still count as one level only.

Use 64490 for the first level treated. This is always required when billing this procedure.

If more than one level is treated:

• Use 64491 for the second level
• Use 64492 for the third level

These are add-on codes and must be billed with 64490.

Determine laterality:

• Bilateral → use -50 (or LT/RT if required by payer)
• Unilateral → use -LT or -RT if needed

Always follow payer-specific rules for modifiers.

Ensure the ICD-10 code supports facet joint pain. Incorrect diagnosis codes can lead to denial, even if the CPT coding is correct.

Before submitting the claim, verify:

• Prior authorization requirements
• Frequency limits
• Modifier preferences

This helps prevent avoidable rejections.

After submission:

• Track claim status
• Address denials quickly
• Correct errors for future claims

Following this process ensures accurate coding, faster reimbursement, and fewer denials.

Accurate documentation is essential for successful billing of CPT 64490–64492. Even correctly coded claims can be denied if the supporting documentation is incomplete or unclear.

• Patient’s chief complaint and pain history
• Duration of pain (typically 3 months or longer)
• Evidence of failed conservative treatments (physical therapy, medications, etc.)
• Diagnosis supporting facet joint-related pain
• Exact levels treated (e.g., C4–C5, T1–T2)
• Laterality (left, right, or bilateral)
• Procedure type (diagnostic or therapeutic)
• Imaging guidance used
• Medication injected and dosage
• Patient’s response to the procedure

Correct coding alone is not enough. Payers require clear evidence that the procedure is medically necessary.

Most U.S. insurers, including Medicare, expect:

• Chronic pain lasting at least 3 months
• Pain suspected to originate from facet joints
• Failure of conservative treatments such as physical therapy or medications
• Clinical findings supporting the procedure

Medial branch blocks are commonly used as diagnostic procedures. They help confirm whether the facet joints are the source of pain.

Many payers require:

• Two diagnostic blocks before approving radiofrequency ablation (RFA)
• Proper documentation of patient response

Medicare and many commercial insurers require:

• At least 80% pain relief following the procedure
• Clear documentation of improvement

This is critical for approval of future treatments.

Most payers limit:

• Number of procedures per year
• Number of levels per session (typically up to 3)

Exceeding these limits may result in denied claims.

Many commercial insurance plans require prior authorization before the procedure. Failure to obtain authorization can lead to full claim denial.

Medicare uses Local Coverage Determinations (LCDs) to define:

• Covered diagnoses
• Documentation requirements
• Frequency limits

Following LCD guidelines is essential for compliance and reimbursement.

Understanding payer expectations helps reduce denials, improve claim approval rates, and ensure long-term compliance.

M47.812 – Cervical spondylosis

M54.2 – Neck pain

M54.6 – Thoracic spine pain

Diagnosis must support facet joint origin.

Applying coding rules to real situations helps ensure accuracy and confidence in billing.

Errors in CPT 64490–64492 coding are common and can directly impact reimbursement. Identifying and avoiding these mistakes helps reduce denials and improve claim accuracy.

Many coders count the number of injections instead of levels. Coding should always be based on facet joint levels, not needle placements.

Codes 64491 and 64492 are add-on codes. They must always be billed with 64490. Billing them alone will result in denial.

Using the wrong modifier or combining modifiers incorrectly can delay or reject claims. Always follow payer-specific rules for -50 vs LT/RT.

Fluoroscopy or CT guidance is often billed incorrectly. These services are already included in CPT 64490–64492.

Missing details such as levels, laterality, or patient response can lead to denial. Complete documentation is essential for medical necessity.

Using diagnoses that do not support facet joint pain can result in rejection. Ensure the diagnosis aligns with the procedure performed.

Billing the same level more than once is a common error. Each level should be reported only once per session.

To avoid these mistakes, you can also explore the advantages of outsourcing in our article on the Benefits of Hiring a Medical Billing Company.

Maximizing reimbursement for CPT 64490–64492 requires accuracy, consistency, and a proactive billing approach.

Always confirm patient eligibility, prior authorization requirements, and payer-specific rules. This helps prevent avoidable denials.

Standardize physician notes to ensure all required details are consistently captured. This improves claim approval rates and reduces errors.

Ensure levels are identified accurately. Undercoding or overcoding directly affects reimbursement.

Use -50 for bilateral procedures or LT/RT modifiers based on payer preference. Incorrect modifiers can delay payments.

Document patient response and pain relief after the procedure. This is critical for future approvals and eligibility for RFA.

Review denied claims and identify patterns. Fix issues quickly to avoid repeated revenue loss.

Medicare and commercial insurers frequently update policies. Staying compliant helps reduce rejections.

Experienced billing teams can reduce coding errors, improve collections, and streamline the revenue cycle.

You can also review key selection factors in What to Look for in a Medical Billing Company.

No. Each level can only be billed once per session, regardless of how many injections are performed at that level.

Bilateral procedures are typically billed using modifier -50. Some payers may require LT and RT modifiers instead. Always verify payer-specific guidelines.

No. Fluoroscopy or CT guidance is already included in these codes and should not be billed separately.

Most payers reimburse for up to three levels per session. Billing beyond this limit may result in denial.

In many cases, yes. Medicare Advantage and commercial insurance plans often require prior authorization before the procedure.

CPT 64490–64492 require accurate coding, proper modifiers, and strong documentation to ensure correct reimbursement. Even small errors can lead to denials and revenue loss.

Summit RCM offers accurate medical billing services designed to simplify this process. With expertise in pain management coding, compliance, and end-to-end revenue cycle management, our team helps reduce denials and improve reimbursement outcomes.

Contact Summit RCM today for a free billing audit and discover hidden revenue leaks within your practice.