CPT code 64451: SI nerve block2026 Medicare rate & RVUs in Massachusetts
Report this code for an image-guided anesthetic or steroid injection targeting nerves that innervate the sacroiliac joint, such as for suspected SI-joint pain.
Medicare pays $251.26–$279.35 for 64451 in the office in Massachusetts, from Rest Of Massachusetts to Metropolitan Boston. Which amount applies depends on the service address.
Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.
On this page 9 sections
What 64451 covers
This service is an injection of anesthetic, steroid, or both around nerves that carry sensation from the sacroiliac joint. Clinicians commonly target the L5 dorsal ramus and sacral lateral branches when evaluating or treating suspected SI-joint pain. Pain medicine physicians, anesthesiologists, and physiatrists may perform it in an office or outpatient facility, using fluoroscopy or CT to guide needle placement.
Report the code when the target is the nerves supplying the SI joint, rather than the joint space itself. The record should identify the side and nerve targets, document image guidance, and describe the injectate and clinical indication. Needle placement and imaging guidance are included. The procedure has a 0-day global period, so same-day preoperative and postoperative care are included. For bilateral services, modifier 50 is paid at 150%. In the same session, the highest-valued procedure is paid in full and other procedures are reduced to 50%. Assistant-at-surgery payment is restricted; co-surgeons and team surgery are not permitted.
This summary was written with AI assistance from CMS physician fee schedule data and checked against the CMS billing rules shown here. Rates on this page come directly from CMS files.
Where 64451 pays more and less in Massachusetts
| Payment locality | Office | Facility |
|---|---|---|
| Metropolitan Boston | $279.35 | $77.56 |
| Rest Of Massachusetts | $251.26 | $73.30 |
How the 64451 rate is calculated
Each of 64451’s three RVUs is multiplied by a geographic index (GPCI) for the payment locality, added up, and multiplied by the conversion factor. Drag the indexes or enter a ZIP to see what moves the rate.
How the rate is built · 64451
RVUs × geographic indexes × conversion factor
Work1.48
1.48 RVUs× 1.000 GPCI
Practice expense5.61
5.61 RVUs× 1.000 GPCI
Malpractice0.14
0.14 RVUs× 1.000 GPCI
Adjusted RVUs
7.2300
Conversion factor
$33.4009
Medicare rate
$241.49
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
Payment rules and modifiers for 64451
The CMS indicators that decide how 64451 is paid alongside other services.
CMS payment indicators · 64451
SI nerve block
| Rule | CMS value | What it means |
|---|---|---|
| Global period | 000 | Same-day global: pre- and post-op care on the day of the procedure is included. |
| Multiple procedures | 2 | Standard reduction: highest-valued procedure at 100%, others at 50%. |
| Bilateral (modifier 50) | 1 | Bilateral with modifier 50 pays 150% of the fee schedule amount. |
| Assistant at surgery (80/81/82/AS) | 1 | Not paid (statutory restriction). |
| Co-surgeons (62) | 0 | Not permitted. |
| Team surgery (66) | 0 | Not permitted. |
| Professional/technical | 0 | Physician service: no professional/technical split. |
What modifiers do to the payment
Modifier 50 · payment effect
With and without the modifier
64451 without 50 · national office
$241.49
SI nerve block
64451-50 · Bilateral: 150%
$362.24
Both sides on one line with modifier 50 are paid at 150% of the fee schedule amount (subject to multiple-procedure rules with other procedures).
64451 compared with similar codes
Compare codes · National
4 codes, side by side
How to choose
- 27096SI joint injection
- Choose 27096 when the needle delivers medication into the SI-joint space. Choose 64451 when the target is the nerves supplying the joint.
- 64625Radiofrequency ablation
- 64625 is for radiofrequency treatment of SI-joint innervation; 64451 reports an injection of anesthetic, steroid, or both.
- 64450Nerve block
- 64450 covers an otherwise unspecified peripheral nerve or branch. Use 64451 when the injection targets nerves innervating the SI joint.
64451 billing questions
How is this different from an SI-joint injection?
This code is for injections targeting nerves that innervate the SI joint. Code 27096 is for an injection into the SI-joint space.
Is image guidance separately reported?
No. The service includes fluoroscopic or CT guidance and needle placement.
Can I report this for both sides?
Yes. Report bilateral work with modifier 50; CMS pays the bilateral procedure at 150%.
How does the multiple-procedure reduction affect same-session services?
CMS pays the highest-valued procedure in full and reduces the other procedures to 50% when performed in the same session.
What documentation supports reporting this code?
Document the SI-innervating nerve targets, laterality, image guidance, injectate, and reason for the injection. The record should make clear that the target is neural, not the joint space.
Where these rates come from
FeeBase calculates base physician payments from CMS work, practice-expense and malpractice RVUs, adjusted by each locality’s geographic indexes and the conversion factor. Services without a published rate are labeled, never given a made-up amount. Amounts are Medicare allowed amounts before claim adjustments: not a patient’s bill or a commercial rate.
CMS RVU26D · effective Oct 1, 2026 through the day before Jan 1, 2027
Show the CMS file lines behind this rate
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