Coding Facet Joint Injections

by  Aimee L. Wilcox, CPMA, CCS-P, CST, MA, MT
Jul 16th, 2014 - Reviewed/Updated Apr 29th

If you work in pain management, anesthesia, or interventional radiology, you are probably keenly aware of the changes that have occurred over the past three years with facet joint injection coding and its effect on your bottom line.

What is a facet joint injection?

A facet joint injection is a diagnostic procedure used to determine if the patient's spine pain is related to arthropathy of the facet joints. During a facet joint block, an anesthetic is injected into the facet joints where the associated spinal nerves travel to see if it will stop or 'block' the pain. Sometimes a steroid is injected with the anesthetic to help with the inflammation.

If the results of the injection prove positive the patient qualifies for a therapeutic procedure called radiofrequency (RF) ablation. (RF) ablation temporarily destroys the affected spinal nerves thereby blocking the pain on a more long-term basis anywhere from six months to a year.

Many patients have back pain which makes this procedure beneficial for many and at the same time ripe for overuse. As such, Medicare has reviewed and researched the effects of this procedure and listed a set of criteria that must be met in order to perform the diagnostic testing and RF ablation. These criteria can be found on the Medicare website.

Payment for services rendered depends on the documentation meeting the criteria put forth by Medicare, so work smartly and efficiently by reviewing the Medicare LCD and make sure your providers are aware of the criteria that must be documented in the patient's record. Let's review the main issues surrounding coding this procedure.

Understanding Spinal Anatomy

Understanding spinal anatomy is the second step to ensuring reimbursement through correct coding. Most coders under or over code facet blocks because of the odd number of nerves to the vertebra that occur in the cervical spine. Let's take a moment and review the spinal anatomy you'll need to know for correct code selection.

• There are four regions of the spine: cervical, thoracic, lumbar and sacral/coccyx. Each region contains numbered vertebrae and numbered nerves
  • Vertebra:
    • Cervical 1-7
    • Thoracic 1-12
    • Lumbar 1-5
    • Sacral 1-5/Coccyx 1-4
  • Nerves:
    • Cervical 1-8
    • Thoracic 1-12
    • Lumbar 1-5
    • Sacral 1-5/Coccyx 1
• The facet joint is a synovial joint located between the superior articular process of one vertebra and the inferior articular process of the vertebra directly above it.
• Facet joints are also referred to as zygapophyseal joints and Z-joints, so watch for these alternative terms in the documentation.
• Each facet joint is innervated by two spinal nerves.
• As there is one more cervical nerve than there are vertebrae, the level listed will no longer match up perfectly starting with the C7-T1 facet joint. Because of the 'extra' C8 nerve, all the nerves of the thoracic, lumbar and sacral/coccygeal regions are innervated by the nerve above and below the facet joint. Example: L4-5 is innervated by "L3, L4" not "L4, L5"

As a coder, make sure you thoroughly understand the nerves assigned to each facet joint well. Anatomy is a must for this procedure.

CPT Code Selection

There are up to three CPT codes used to report facet joint injections based on the spinal region. The codes allow for three levels maximum per session. Anything over three is considered free of charge, as they will not be reimbursed.

Cervical/Thoracic Facet Joints:
64490    First facet joint level 
64491    Second facet joint level
64492    Third and all remaining facet joint levels (only bill once for all remaining levels 3+)

Lumbar/Sacral Facet Joints:
64493    First facet joint level
64494    Second facet joint level
64495    Third and all remaining facet joint levels (only bill once for all remaining levels 3+)

As of 2012, the codebook clarifies that injections to the T12-L1 joint (or the nerves that innervate that joint) should be reported using 64490.

Industry Standard Documentation Aids Code Selection

The next major issue with coding facet joint injections correctly is understanding the documentation. There is an industry-standard way to document facet joint injections. When providers do not follow industry-standard documentation practices over-coding or under-coding usually occurs.

Let's review the documentation issues you may encounter and what they mean:

1. Standard documentation lists the facet joint to be blocked with hyphens.
   
   Example A:  L4-5 or L4-L5
   Coding:  Each facet joint = one level code. CPT code is 64493
   
   Example B:  Facet joints blocked include right C3-4, C4-5, C5-6
   Coding:  64490-RT, 64491-RT, 64492-RT
   
   
2. Another common way to document facet injections is to document the individual nerves blocked, separated by commas.
   
   When coding from nerves blocked, use the formula:  Nerves minus one nerve = levels billed. (N-1=levels)
   
   This takes into consideration that two nerves for each level were injected.
   
   Example:  Nerves blocked include L2, L3, L4, L5
   Formula: 4 nerves - 1 = 3 levels billed 
   Coding: 64493-LT, 64494-LT, 64495-LT

Physicians who are aware of this confusing issue may simply document both for clarity. Example: "Nerves C4, C5, and C6 were blocked targeting the C4-5 and C5-6 facet joints."

Let's look at some examples:

1. Facet block, right L4-5 was performed today.
   Codes:  64493-RT. 
   Explanation:  This is listed as a facet joint (separated by a hyphen), meaning two nerves were injected (L3, L4) on the right side.
   
   
2. Facet block, left C4, C5, C6 nerves listed by nerve blocked separated by comma so use the formula N - 1 = number of levels:
   Codes:  64490-LT, 64491-LT
   
   
3. Nerves blocked right T3, T4, T5, T6 targeting the T4-5, T5-6, T6-7 (both are listed)
   Codes:  64490-RT, 64491-RT, 64492-RT

Staying up-to-date on recent changes and the standard methods of coding facet joint injection is critical to your provider's practice and your bottom line.

About Aimee L. Wilcox, CPMA, CCS-P, CST, MA, MT

Aimee L. Wilcox is a medical coding, billing, and auditing consultant, author, and educator with more than 30 years of clinical and administrative experience in healthcare, coding, billing, and auditing. Medicine, including coding and billing, is a constantly changing field full of challenges and learning and she loves both. Aimee believes there are talented medical professionals who, with proper training and excellent information, can continue to practice the art of healing while feeling secure in their billing and reimbursement for such care.