Surgical · Other

Genioplasty using a sliding osteotomy technique, single bone segment — repositions the chin by cutting and advancing or setting back a single piece of the mandibular symphysis.

Verified May 8, 2026 · 6 sources ↓

Medicare: $649.98
Total RVUs: 19.46
Global, days: 90
Region: Other

Drawn from CMSFastrvuAAPCGenhealthPayerprice

Documentation requirements

What must appear in the operative or office note to support the claim.

Source · Editorial brief grounded in 6 cited references ↓

Diagnosis driving medical necessity — document whether indication is dentofacial deformity, obstructive sleep apnea, or traumatic deformity versus cosmetic; payers deny without this distinction
Operative note must specify single-piece osteotomy technique and confirm no interpositional bone graft was placed (absence of graft separates 21121 from 21123)
Fixation method documented — plate and screw type, size, and placement; relevant for any future removal coding
Pre-op imaging (cephalometric radiographs or CT) in the record confirming the skeletal deformity and surgical plan
For sleep apnea indication, include prior sleep study results and documentation that conservative measures were trialed or contraindicated
Anesthesia type confirmed as general or monitored anesthesia care — genioplasty is not performed under local alone in standard practice

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity 51 Multiple procedures 52 Reduced services 57 Decision for surgery 58 Staged or related 62 Co-surgeons 78 Unplanned return — related 79 Unrelated during global 80 Assistant surgeon AS PA/NP/CNS assistant

What this code covers

Source · Editorial summary grounded in 6 cited references ↓

CPT 21121 covers a sliding genioplasty in which the surgeon makes an intraoral incision, performs a single horizontal osteotomy through the chin segment of the mandible, and repositions that single bone piece anteriorly, posteriorly, or vertically before fixing it with plates and screws. The procedure addresses microgenia, chin asymmetry, dentofacial deformities, or obstructive sleep apnea when chin advancement supports airway patency. Medical necessity documentation must distinguish this from a purely cosmetic request — payers scrutinize that distinction closely.

This code sits in the genioplasty family alongside 21120 (augmentation with implant or graft), 21122 (sliding osteotomy, two or more cuts — e.g., wedge excision for asymmetry), and 21123 (sliding with interpositional bone graft). Picking the wrong sibling code is a frequent audit trigger. Use 21121 only when a single-piece osteotomy is performed without additional osteotomies and without interpositional grafting. If the surgeon harvests and places autograft within the gap, 21123 applies instead.

The 90-day global period means all routine post-op visits, wire adjustments, and wound checks through day 90 are bundled. Complications requiring a return to the OR for a related issue (hardware failure, infection requiring washout) bill under modifier 78. An unrelated surgical procedure in the same global window needs modifier 79. Separate E/M services within the global period require modifier 24 to clear.

RVU & reimbursement

Component RVUs and Medicare national rate. Actual payment varies by GPCI locality.

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	7.61
Practice expense RVU	10.98
Malpractice RVU	0.87
Total RVU	19.46
Medicare national rate	$649.98
Global period	90 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	$649.98
HOPD (APC 5164) Hospital outpatient department	$3,387.27
ASC (PI J8) Ambulatory surgical center (freestanding)	$2,153.56

Common denial reasons

The recurring reasons claims for CPT 21121 get rejected.

Source · Editorial brief grounded in CMS NCCI edits, AAOS coding appeals, and cited references ↓

Cosmetic versus reconstructive not clearly established — payer denies as cosmetic when operative note and diagnosis codes don't explicitly support medical necessity
Upcoding to 21122 or 21123 when only a single-piece osteotomy without grafting was performed — or downcoding to 21120 when an osteotomy rather than an implant augmentation was done
Missing or inadequate prior authorization — most commercial payers require pre-auth for genioplasty procedures, and oral/maxillofacial cases routed through medical rather than dental benefits add an extra auth layer
ICD-10 code mismatch — billing M26.09 (mandibular skeletal deformity) against a payer policy that only covers specific codes such as Q18.4 or Q67.4 without additional documentation

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 6 cited references ↓

01When does 21121 cross into 21122 territory?

Use 21122 when the surgeon makes two or more osteotomy cuts — for example, a wedge excision or bone wedge reversal to correct chin asymmetry. A single horizontal cut repositioning one piece stays at 21121.

02Can 21121 and 21123 ever be billed together?

No. 21123 already includes obtaining and placing an autograft within the osteotomy gap. If that's what was done, bill 21123 only. 21121 is the correct code when the single-piece bone segment is moved and fixed without grafting.

03Does Medicare cover sliding genioplasty under 21121?

Medicare covers it when medical necessity is established — most commonly for dentofacial deformity or as part of documented OSA surgical management. Purely cosmetic cases are non-covered. Get a signed ABN when necessity is borderline.

04What modifier applies when genioplasty is performed same-day with orthognathic surgery?

Modifier 51 (multiple procedures) applies to the secondary procedure. If genioplasty is the lesser-valued code, append 51 to 21121. Confirm NCCI edits aren't creating a bundle before billing both codes together.

05How is the 90-day global period managed for post-op occlusal adjustments and follow-up imaging?

Routine occlusal checks and follow-up clinical visits are bundled into the global. Imaging ordered solely to evaluate healing is also generally bundled. If a new problem or unrelated condition requires a separate E/M, use modifier 24.

06Is modifier 62 (co-surgery) appropriate for 21121 when an oral surgeon and plastic surgeon operate together?

Yes, when both surgeons each perform a distinct portion of the procedure and each dictates their own operative note documenting their specific contribution. Each surgeon appends modifier 62 and bills 21121 — payment splits per CMS co-surgery rules.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

Mira AI Scribe

Mira's AI scribe captures the osteotomy technique (single-piece, no interpositional graft), the direction of movement (advancement, setback, or vertical repositioning), fixation hardware used, and the clinical indication tied to the procedure. That documentation chain prevents the two most common denials: cosmetic-versus-reconstructive ambiguity and wrong-sibling-code selection between 21121, 21122, and 21123.

See how Mira captures CPT 21121 documentation