Injection of anesthetic, steroid, or both around the nerves that supply the sacroiliac joint, performed under fluoroscopic or CT guidance.
- Medicare
- $241.49
- Work RVU
- 1.48
- Global, days
- 0
- Region
- Spine
Documentation requirements
What must appear in the operative or office note to support the claim.
Source · Editorial brief grounded in 3 cited references ↓
- Side or sides and nerves targeted
- Imaging modality with saved images
- Drug and volume at each target
- Exam findings pointing to the SI joint
- Pre-block and post-block pain scores with timing
- Plan for radiofrequency ablation if relief is achieved
Applicable modifiers
Modifiers commonly billed with this code.
Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual
What this code covers
Source · Editorial summary grounded in 3 cited references ↓
64451 covers blocking the nerves that supply the sacroiliac joint, usually the lateral branches of the sacral dorsal rami, under fluoroscopy or CT. It is most often a diagnostic step before radiofrequency ablation with 64625. An intra-articular SI joint injection is a different code, 27096.
Imaging is part of the code, so do not add 77003 or 77012. The descriptor names fluoroscopy or CT only. CPT guidance sends an ultrasound-guided SI nerve block to the unlisted nerve code (64999).
In an ortho spine practice, these blocks come up when a patient's back pain is traced to the SI joint and the plan is ablation. Many payers want two diagnostic blocks with documented relief before they authorize the RFA, and they look for pain scores in the hours after each block. One unit per side. Bilateral blocks use modifier 50 or RT and LT. Global period is 0 days. Same-day E/M needs modifier 25 and its own problem.
RVU & reimbursement
Component RVUs and Medicare national rate. Actual payment varies by GPCI locality.
Source · CMS Physician Fee Schedule, RVU26A · January 2026
Work RVU vs. total RVU
The work RVU (1.48) is the surgeon's own effort — the figure physician pay and productivity targets are built on. The total RVU (7.23) adds practice overhead and malpractice, and is what drives the Medicare payment below.
| Work RVU | 1.48 |
| Practice expense RVU | 5.61 |
| Malpractice RVU | 0.14 |
| Total RVU | 7.23 |
| Medicare national rate | $241.49 |
| Global period | 0 days |
Payment by site of service
Medicare pays different rates by setting. HOPD typically pays substantially more than ASC for the same procedure.
Source · CMS OPPS Addendum B·ASC HCPCS payment rates·2026
| Setting | Medicare rate (national) |
|---|---|
Office (PFS non-facility) Procedure performed in physician's office | $241.49 |
HOPD (APC 5442) Hospital outpatient department | $721.17 |
ASC (PI G2) Ambulatory surgical center (freestanding) | $387.46 |
Common denial reasons
The recurring reasons claims for CPT 64451 get rejected.
Source · Editorial brief grounded in CMS NCCI edits, AAOS coding appeals, and cited references ↓
- Intra-articular SI joint injection billed as 64451 instead of 27096
- Fluoroscopy billed separately
- Block done under ultrasound
- Missing post-block pain diary for diagnostic blocks
- Bilateral block without 50 or RT and LT
- Frequency exceeds payer limits
Frequently asked questions
Source · Generated from the editorial pipeline, verified against 3 cited references ↓
01What is the difference between 64451 and 27096?
02Is fluoroscopy included in 64451?
03Can 64451 be billed with ultrasound guidance?
04Do payers require SI nerve blocks before RFA?
Sources & references
Editorial content was developed using the following public sources.
Mira Scribe
Mira Scribe's notes capture SI joint exam findings and post-block relief in a consistent format, which is what payers use to approve the ablation that follows.
See how Mira captures CPT 64451 documentation