Facing the Challenges of Facet Joint Inject Coding to Foster Success

As 2025 comes to a close and 2026 approaches, interventional radiology (IR) professionals are facing mounting uncertainty. From looming payment reductions and evolving compliance requirements to the continued complexity of pain management coding, a storm of problems could sweep you off your feet. Even minor coding missteps can trigger denials, reduced reimbursement, and compliance risk at a time when every dollar matters more than ever. This month, we dive into facet joint injection coding with a real-world case example that unlocks precision, dodges costly errors, and protects revenue in an increasingly challenging reimbursement landscape.

Dissecting Injection Coding Insight

First know that every vertebra is connected to the ones above and below by facet joints, which provide flexibility and movement to the spine. Each pair of vertebrae has two facet joints, one on each side. A facet joint consists of small, bony projections along the back of the spine that interlock to form a joint connecting the vertebrae.

As we age or experience injury, the smooth movement of these joints can be disrupted, causing the bones to rub together. This can result in pain and inflammation. To relieve symptoms, steroid and/or anesthetic injections may be administered directly into the facet joint or the nerves supplying it.

These codes are used for injections targeting the facet joint itself or the nerves that innervate it. For example, a physician may perform a “medial branch block.” Since medial branch nerves supply the facet joints, this procedure is coded as a facet joint block. Understand that codes are applied per facet joint, not per vertebra or nerve. Each joint receives innervation from nerves at its own level and the level above. For instance, the L4-L5 facet joint is served by the L3 and L4 medial branch nerves. Physician documentation remains an area that is lacking in terms of understanding and often a critically missed area in regard to accuracy when it comes to coding submission. Always confirm with the physician whether the documentation specifies nerves rather than facet joints.

If the procedure is performed on the left side at one level and the right side at a different level within the same spinal region, report one unit for the primary procedure and one unit for the add-on code. For procedures performed bilaterally at one level and unilaterally at another, report one unit of the primary procedure for each level and include modifier 50 for the bilateral injection. Under the scenario that  injections are performed unilaterally at multiple levels, report one unit of the primary procedure per level along with the appropriate add-on codes.

Codes 64490–64495 are assigned when facet joint injections are performed under fluoroscopic or CT guidance. Note that you may not code 77003 or 77012 as additional codes.

CASE: SYNOVIAL CYST ASPIRATION AND FACET INJECTION

Left L4-L5 facet arthrogram and steroid/anesthetic injection with fluoroscopic guidance and separate left sided paraspinous dorsal synovial cyst aspiration and steroid/anesthetic injection with ultrasound guidance.

Indication: The patient does have left paraspinous mechanical back pain that worsens with twisting his torso. He has some tenderness at the lumbosacral junction on the left. Previous MR imaging has demonstrated enlarging synovial cyst dorsal to the lower lumbar spine. An L5-S1 cyst was described and requested to be aspirated. I reviewed the previous MR imaging. I feel that the dorsal paraspinous synovial cyst at the L5 level is actually clearly from the L4-L5 facet joint and not the L5-S1 facet joint.

I discussed this with the patient and from the beginning we planned to aspirate and inject the left sided dorsal paraspinous cyst but also access and inject if possible, the left L4-L5 facet joint. Ultrasound guided dorsal paraspinous synovial cyst puncture, aspiration and steroid injection: Prior to the procedure, using fluoroscopy to guide the ultrasound, the dorsal paraspinous enlarging cyst at the L5 level which is felt to arise from the L4-L5 facet joint on review of previous imaging was easily identified.

After local anesthesia, a 20-gauge spinal needle was placed into this cyst and 0.5 cc of straw-colored fluid was aspirated. This was sent for cell count, Gram stain and cultures. After the facet injection,

I did inject the cyst with approximately 30% of a mixture of 1 cc 40 mg Kenalog and 1 cc 25% bupivacaine. Fluoroscopically guided left L4-L5 facet joint injection: Review of the imaging previously suggested that the best access to the very degenerative left L4-L5 facet joint was from a caudal approach. With cranial angulation, I was able to isolate the caudal aspect of the joint and with some effort and local anesthesia and fluoroscopic guidance, a 20-gauge spinal needle was directed into the joint. Intra-articular contrast documented intra-articular position. Approximately 70% of a mixture of 1 cc 40 mg Kenalog and 1 cc 25% bupivacaine was injected. After the procedure, the patient was quite happy, he was able to rotate his torso without any discomfort and felt that there was a dramatic improvement of his symptoms with the steroid/anesthetic mixture.

Impression: 1. Successful uncomplicated ultrasound-guided puncture, aspiration and steroid/anesthetic mixture of a dorsal left L5 region synovial cyst which is felt to arise from the left L4-L5 facet joint and not the L5-S1 facet joint. 2. Successful uncomplicated fluoroscopically guided left L4-L5 facet joint arthrogram with injection of a steroid/anesthetic mixture. 3. Apparent substantial positive initial response to the injection which included bupivacaine as well as Kenalog as described above.

Thank you for this referral.

CODE ASSIGNMENTS AND RATIONALE

According to the AMA, aspiration and injection of a lumbar synovial cyst would be reported with code 64999. A guidance code would not be assigned as it would be included in the unlisted code. The facet joint injection is separately coded. Code 64493 includes fluoroscopy, do not also code 77003.

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With every dollar of reimbursement counting more than ever in the face of payment decline and complex changes, it’s imperative to make sure your CPT^®coding is correct and compliant. Master more coding topics and break down the complexity with our 2025 Pain Management Interventional Radiology Coding live on November 12, 2025 at 11:00 am CT (120 minutes) or on demand past this date. This webcast is an essential training tool for both audio and visual learners.