CPT code 64646: Muscle chemodenervation, trunk, one to five muscles2026 Medicare rate & RVUs in Missouri
Reports botulinum toxin chemodenervation of one to five trunk muscles to manage focal muscle overactivity, such as truncal spasticity or dystonia.
Medicare pays $156.75–$165.79 for 64646 in the office in Missouri, from Rest of Missouri to Metropolitan St. Louis, MO. 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.
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What 64646 covers
A clinician injects a chemodenervating agent, commonly botulinum toxin, into one to five trunk muscles to reduce focal overactivity. Neurologists, physiatrists, and other clinicians who treat spasticity or dystonia may perform the service in an office or outpatient procedure setting. Trunk targets can include paraspinal or abdominal muscles; this code is not for injections into limb muscles or eccrine glands.
Select the code by the number of distinct trunk muscles treated during the session, not by the number of injection sites or toxin units. Document the treated muscles, clinical indication, and injection details. Use the six-or-more-muscle trunk code when that threshold is reached. The service has a 0-day global period, so same-day preoperative and postoperative care is included. When multiple procedures occur in one session, the highest-valued procedure is paid in full and others at 50%. Modifier 50 is inappropriate. Assistant-at-surgery payment is statutorily 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 64646 pays more and less in Missouri
The same RVUs, adjusted for each area’s costs. Open a locality for its calculation, history and nearby areas.
3 payment localities
$156.75 to $165.79
| Payment locality | Office | Facility |
|---|---|---|
| Metropolitan Kansas City, MO | $164.15 | $101.74 |
| Metropolitan St. Louis, MO | $165.79 | $102.51 |
| Rest of Missouri | $156.75 | $99.45 |
How the 64646 rate is calculated
Each of 64646’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 · 64646
RVUs × geographic indexes × conversion factor
Work1.76
1.76 RVUs× 1.000 GPCI
Practice expense2.86
2.86 RVUs× 1.000 GPCI
Malpractice0.48
0.48 RVUs× 1.000 GPCI
Adjusted RVUs
5.1000
Conversion factor
$33.4009
Medicare rate
$170.34
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
Payment rules and modifiers for 64646
The CMS indicators that decide how 64646 is paid alongside other services.
CMS payment indicators · 64646
Muscle chemodenervation, trunk, one to five muscles
| 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) | 0 | The 150% bilateral adjustment doesn’t apply. |
| 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 51 · payment effect
With and without the modifier
64646 without 51 · national office
$170.34
Muscle chemodenervation, trunk, one to five muscles
64646-51 · Second procedure: 50%
$85.17
When this isn’t the highest-valued procedure in the session, Medicare pays 50% of its fee schedule amount (the highest is paid at 100%).
64646 compared with similar codes
Compare codes · National
4 codes, side by side
How to choose
- 64647Trunk chemodenervationSix or more muscles
- Both cover trunk muscle chemodenervation; choose 64646 for one to five muscles and 64647 for six or more.
- 64642ChemodenervationOne extremity, 1–4 muscles
- 64642 applies to one extremity with one to four muscles treated. Use 64646 for trunk muscles.
- 64644Muscle chemodenervationOne extremity, five or more muscles
- 64644 applies to one extremity with five or more muscles treated; 64646 is for one to five trunk muscles.
64646 billing questions
How is this code distinguished from the six-or-more trunk muscle code?
Count the distinct trunk muscles treated during the session. Report this code for one to five muscles and the six-or-more code when at least six are treated.
Do injection sites or toxin units determine the code?
No. The threshold is based on the number of trunk muscles treated, not the number of needle placements or units of medication.
Can modifier 50 be used for bilateral trunk injections?
No. CMS identifies bilateral adjustment as inappropriate for this code; do not use modifier 50 to represent treatment on both sides.
Is same-day evaluation or postoperative care separately included?
The code has a 0-day global period, with same-day preoperative and postoperative care included.
How are other procedures in the same session paid?
Under the standard multiple procedure reduction, the highest-valued procedure is paid in full and other procedures are paid at 50%.
Can an assistant, co-surgeon, or surgical team be reported?
Assistant-at-surgery payment is statutorily restricted. Co-surgeons and team surgery are not permitted for this code.
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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