CPT code 21123: Chin augmentation, sliding osteotomy with graft2026 Medicare rate & RVUs in Maryland
Sliding genioplasty with an interpositional bone graft repositions the chin segment while adding projection or height for selected chin deficiencies.
CMS doesn’t publish an office rate for 21123 in Maryland.
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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On this page 9 sections
What 21123 covers
A surgeon cuts and moves the chin portion of the mandible, then places bone between the repositioned segment and the remaining jaw to augment the chin. This approach may be selected when sliding the bone alone would leave a gap or provide insufficient projection or height. Oral and maxillofacial, plastic, or craniofacial surgeons typically perform the operation in a hospital or ambulatory surgical setting.
Report 21123 when the operative record supports both a sliding chin osteotomy and augmentation with an interpositional graft. Document the osteotomy, the segment’s repositioning, and the graft placement; simple augmentation without sliding or a sliding osteotomy without grafting points to a different code. CMS assigns a 90-day global period, including the day-before preoperative visit and 90 days of related postoperative care. When multiple procedures occur in the same session, the highest-valued procedure is paid in full and other procedures are subject to the standard 50% reduction. Assistant-at-surgery payment may be available; co-surgeon payment requires supporting documentation, and team-surgery payment is 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 21123 pays more and less in Maryland
The same RVUs, adjusted for each area’s costs. Open a locality for its calculation, history and nearby areas.
| Payment locality | Office | Facility |
|---|---|---|
| Baltimore area, MD | Unavailable | $822.46 |
| Rest of Maryland | Unavailable | $781.45 |
| Washington, DC area | Unavailable | $867.07 |
How the 21123 rate is calculated
Each of 21123’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 · 21123
RVUs × geographic indexes × conversion factor
Work11.06
11.06 RVUs× 1.000 GPCI
Practice expense10.62
10.62 RVUs× 1.000 GPCI
Malpractice1.61
1.61 RVUs× 1.000 GPCI
Adjusted RVUs
23.2900
Conversion factor
$33.4009
Medicare rate
$777.91
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
Payment rules and modifiers for 21123
21123 has a 90-day global period: related visits in that window are included in the surgery payment.
CMS payment indicators · 21123
Chin augmentation, sliding osteotomy with graft
| Rule | CMS value | What it means |
|---|---|---|
| Global period | 090 | Major surgery: the day before, the day of, and 90 days after are 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) | 2 | Paid. |
| Co-surgeons (62) | 1 | Permitted with supporting documentation. |
| Team surgery (66) | 0 | Not permitted. |
| Professional/technical | 0 | Physician service: no professional/technical split. |
| Split (54/55/56) | 0.10/0.69/0.21 | Share of the payment for pre-op, the procedure itself, and post-op care. |
Global surgery period · 21123
Chin augmentation, sliding osteotomy with graft
90-day global period ends
Dec 30, 2026
Covers Sep 30, 2026 through Dec 30, 2026 (92 days, including the day before surgery).
Visit on Oct 31, 2026
Day 30 of the 90-day post-op period: related follow-up care is included in the surgical payment.
Pre-op dayGlobal period
What modifiers do to the payment
Modifier 51 · payment effect
With and without the modifier
21123 without 51 · national facility
$777.91
Chin augmentation, sliding osteotomy with graft
21123-51 · Second procedure: 50%
$388.96
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%).
21123 compared with similar codes
Compare codes · National
5 codes, side by side
How to choose
- 21120Chin augmentationAugmentation without sliding osteotomy
- Choose 21120 for chin augmentation without a sliding osteotomy. 21123 involves moving the chin segment and augmenting it with an interpositional graft.
- 21121Sliding genioplastySingle-piece osteotomy
- 21121 is a single-piece sliding genioplasty without the graft augmentation represented by 21123.
- 21122Sliding genioplastyTwo or more osteotomies
- 21122 describes sliding genioplasty with two or more osteotomies. 21123 is distinguished by interpositional graft augmentation.
- 21125Mandibular augmentationProsthetic material
- 21125 addresses augmentation of the mandibular body or angle; 21123 is for sliding repositioning and graft augmentation of the chin.
21123 billing questions
How is 21123 different from 21121?
21123 describes a sliding chin osteotomy with interpositional graft augmentation. Use 21121 for a single-piece sliding genioplasty without that graft augmentation.
Can 21123 be reported with 21120 for the same chin?
Do not report a second genioplasty code for the same chin work simply to represent the graft. Choose the code that matches the operation performed.
Should modifier 50 be appended for work on both sides?
No. CMS identifies bilateral adjustment as inappropriate for this code; modifier 50 does not describe the midline chin procedure.
What documentation supports reporting 21123?
The operative report should identify the sliding osteotomy, how the chin segment was repositioned, and placement of an interpositional bone graft for augmentation.
How does the 90-day global period affect postoperative visits?
The day-before preoperative visit and 90 days of related postoperative care are included in the global period.
Can an assistant or co-surgeon be reported?
Assistant-at-surgery payment may be available. Co-surgeon payment requires supporting documentation; team-surgery payment is not permitted.
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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