CPT Coding for Paravertebral Facet Joint Injections – the Impact of Laterality

Paravertebral facet/facet joints (also known as zygapophysial joints) are paired joints, with one pair at each vertebral level, located on the back of the spine, where one vertebra slightly overlaps another. These joints guide and restrict the spine's movement to help move and stabilize the spinal column. Facet joints have a cartilage surface like other joints in the body, such as the hip or knee.

Image courtesy of Wikimedia Commons
https://commons.wikimedia.org/wiki/Main_Page

Facet joints are innervated by spinal nerves and a single joint may be innervated by multiple nerves. A facet joint injection is a type of nerve block performed to determine whether a facet joint is a source of pain or to deliver pain control for the spinal nerve area.

Codes 64490, +64491, +64492, 64493, +64494, +64495 describe the introduction/injection of a diagnostic or therapeutic agent into the facet joint, or into the nerves that innervate that joint, by vertebral level.

Facet joint injection coding is influenced by:

• Number of levels treated
  • First
  • Second
  • Three or more
• Number of sides treated (laterality)
  • Right
  • Left
  • Both (bilateral)
• Vertebral region (Cervical/Thoracic) or (Lumbar/Sacral)

CPT Guidelines

The first step is reviewing the documentation to determine how many vertebral levels were injected and which vertebral region(s) those levels belong to. Laterality does not factor into determining the number of levels injected.

Examples:

• Injection of the right L3-L4 facet joint is injection at a single level in the lumbar vertebral region.
• Injection of the right and left L3-L4 facet joints is also injection at a single level in the lumbar vertebral region.
• Injection of the left T6-T7-T8 (T6-T7, T7-T8) facet joints is injection at two levels in the thoracic vertebral level.

• Even if multiple nerves of the same joint are injected, this is still considered a single level.

Once the number of levels has been calculated, the type and number of codes for each level of injection(s) has to be determined.

For the type of codes:

• Injection(s) at the first level is/are reported with a primary CPT code
  • Cervical/Thoracic - 64490
  • Lumbar/Sacral – 64493
• Add-on codes are used to report injections of a second, third or more levels during the same session
  • Cervical/Thoracic - +64491 (second), +64492 (third or more)
  • Lumbar/Sacral - +64494 (second), +64495 (third or more)
• Add-on codes are not used to report injections of an additional joint at the same level.
• Do not combine add-on codes from one region with primary codes from another region. If injections are performed in different regions (e.g., thoracic and lumbar), each region is coded independently, starting with a primary code for each region.

Number of codes reported per level is impacted by laterality.

Unilateral Injections

Unilaterality is dependent upon performance of injection of a single side per vertebral level, not the specific side (right or left) on which the injections are performed.

• When one level is injected unilaterally, report one code, the primary procedure code specific to the vertebral region being injected (64490/64493).
• If multiple levels are injected unilaterally:
  • Report a primary procedure code specific to the vertebral region being injected (64490/64493)
    • If unilateral injections are given in more than one region (e.g., thoracic and lumbar), a primary code will be assigned for the first level in each region.
  • Report the appropriate add-on code(s) based on the region(s) being injected and the number of levels injected.

Bilateral Injections

Bilaterality is dependent upon performance of injections of both the right and left facet joint of the same vertebral level.

• When one level is injected bilaterally, report one code, the primary procedure code, specific to the vertebral region being injected (64490/64493), with modifier -50.
• If multiple levels are injected bilaterally:
  • Report a primary procedure code specific to the vertebral region being injected (64490/64493), with modifier -50.
    • If bilateral injections are given in more than one region (e.g., thoracic and lumbar), a primary code with modifier -50 will be assigned for the first level in each region.
• Report two units (“x2”) of the appropriate add-on code(s) based on the region(s) being injected and the number of levels injected. Do NOT use modifier -50.

Combined Unilateral and Bilateral Injections

• When one level is injected bilaterally and a different level(s) is injected unilaterally within the same vertebral region:
  • Report the primary procedure code specific to the region being injected (64490/64493) and append modifier -50 for the bilateral procedure.
  • Report the appropriate add-on code(s) dependent on the number of levels being injected.
• When unilateral and/or bilateral injections are performed in different vertebral regions:
  • Follow the guidelines for unilateral and bilateral injections independently for each region.

Medicare Exceptions

The direction provided above is in accordance with CPT coding guidance. In some cases, payers, including Medicare, may require reporting and modifier usage that differs from the guidance found in the CPT coding manual. This is the case when coding bilateral facet joint injections for Medicare billing. Medicare accepts the same codes to report these procedures for their beneficiaries, but follows a different policy related to the use of modifiers vs. double code reporting as outlined below:

• Each unilateral or bilateral intervention at any level should be reported as one unit, with bilateral intervention signified by appending the modifier -50.
• Bilateral paravertebral facet injection procedures 64490 through 64495 should be reported with modifier -50.
• For services performed in an ASC, physicians must continue to use modifier -50. Only the ASC Facility itself must report the applicable procedure code on two separate lines, with one unit each and append the -RT and -LT modifiers to each line.

Note: The direction outlined here on modifier usage follows the guidance provided in the CPT coding manual and the Medicare Coverage Database, however other payers may still have even different requirements for using modifier -50 or reporting codes twice for bilateral procedures. Always check the payer’s requirements for modifier usage to ensure correct reporting.

Please refer to the additional guidelines and parenthetical instructional notes associated with codes 64490 to +64495 for complete direction regarding assignment of codes for paravertebral joint injections.

Summary Tables

These tables summarize facet joint injection coding by number of levels, laterality and vertebral region. Note the differences in coding for Medicare beneficiaries depending on type of provider and place of service.

Note: When you see the notation “x 2” in the table below, that means to report the same code twice. Each code will appear on two separate lines on the billing form.

Example:

A patient presents to the hospital same day surgery department for facet joint injection to treat lumber spondylosis. She receives injection of three nerves in the right facet joint at L3-L4, three nerves in the left facet joint at L3-L4, two nerves in the right facet joint at L4-L5 and two nerves in the left facet joint at L4-L-5.

Code assignment based on CPT guidance: 64493-50, +64494, +64494

Code assignment based on Medicare guidance: 64493-50, +64494-50

Take Aways

• Facet joint injections are performed to determine whether a facet joint is a source of pain or to deliver pain control for the spinal nerve area.
• Unilateral injections are those performed on a single joint (right or left) as a specific vertebral level.
• Bilateral injections are those performed on both joints (right and left) at a specific vertebral level.
• If injections are performed in different regions (e.g., thoracic and lumbar), each region is coded independently, starting with a primary code for each region.
• For bilateral procedures, CPT guidelines direct the use of modifier -50 for reporting of the primary code and double code reporting for add-on codes.
• Coding for Medicare beneficiaries requires using modifier -50 rather than double code reporting unless you are reporting for an ASC.

For expanded instruction in coding for nerve blocks, take our HIALearn course Nerve Block Coding in CPT.

References

• CPT Coding Manual 2025
• CPT Assistant, August 2024, Volume 34, Issue 7, page 1
• CPT Assistant, May 2020, Volume 30, Issue 5, page 14
• CPT Assistant, May 2018, Volume 28, Issue 5, page 10
• CPT Assistant, February 2015, Volume 25, Issue 2, page 9
• https://www.cms.gov/medicare-coverage-database/view/article.aspx?articleId=57826&Cntrctr=297&ContrVer=1&CntrctrSelected=297*1&DocType=Active

Since 1992, HIA has been the leading provider of compliance audits, coding support services and clinical documentation audit services for hospitals, ambulatory surgery centers, physician groups and other healthcare entities. HIA offers PRN support as well as total outsource support.

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.