Reduction of forehead contour with prosthetic implant placement, performed as a single operative session to reshape the frontal bone and restore contour using an alloplastic or custom implant.
Verified May 8, 2026 · 4 sources ↓
- Medicare
- $826.67
- Work RVU
- 12.55
- Global, days
- 90
- Region
- Other
Documentation requirements
What must appear in the operative or office note to support the claim.
Source · Editorial brief grounded in 4 cited references ↓
- Operative note must explicitly document bone reduction of the forehead contour — not just implant placement alone, which would misrepresent the procedure
- Identify the prosthetic material by type (alloplastic, custom PEEK, methylmethacrylate, or other) and confirm implant placement in the note
- Preoperative imaging (CT preferred) documenting the degree of frontal bossing or contour deformity requiring surgical correction
- Diagnosis code must support medical necessity — congenital skull deformity, craniofacial anomaly, or other qualifying diagnosis; cosmetic-only indications will be denied by Medicare
- If prior authorization was obtained, attach the authorization number and confirm the authorized code matches 21138 (not 21137 or 21139)
- Document that the frontal sinus was not set back — if sinus setback was performed, 21139 is the correct code, not 21138
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 4 cited references ↓
CPT 21138 covers surgical reduction of forehead contour combined with prosthetic implant placement. The procedure addresses prominent supraorbital ridges or frontal bossing — the surgeon reduces the bony contour and fills the resected area with an implant to achieve the target forehead shape. It sits between 21137 (contouring only, no implant) and 21139 (contouring with frontal sinus setback), so the operative note must confirm both components: bone reduction and prosthetic placement.
The 90-day global period covers the day-before visit, the surgery itself, and all routine postoperative care through day 90. Any unrelated procedure billed during that window requires modifier 79. A complication requiring return to the OR for a related reason — implant displacement, wound dehiscence repair — bills under modifier 78. Separate E/M visits during the global need modifier 24 with documentation of a distinct, unrelated presenting problem.
Payer coverage for 21138 varies sharply by indication. Billed for congenital skull deformity or craniofacial anomaly in pediatric patients, the claim typically travels a different medical-necessity path than the same code billed for gender-affirming facial surgery in adults. Both require diagnosis-specific documentation, but commercial payers handling gender-affirming care apply plan-specific criteria that Medicare does not govern. Confirm prior authorization requirements before scheduling.
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 (12.55) is the surgeon's own effort — the figure physician pay and productivity targets are built on. The total RVU (24.75) adds practice overhead and malpractice, and is what drives the Medicare payment below.
| Work RVU | 12.55 |
| Practice expense RVU | 9.86 |
| Malpractice RVU | 2.34 |
| Total RVU | 24.75 |
| Medicare national rate | $826.67 |
| 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 | $826.67 |
HOPD (APC 5165) Hospital outpatient department | $6,048.05 |
ASC (PI G2) Ambulatory surgical center (freestanding) | $3,025.62 |
Common denial reasons
The recurring reasons claims for CPT 21138 get rejected.
Source · Editorial brief grounded in CMS NCCI edits, AAOS coding appeals, and cited references ↓
- Cosmetic exclusion: payer determines the forehead reduction lacks a covered medical indication, triggering a blanket cosmetic denial
- Wrong code level: claim submitted as 21138 when only contouring was performed without a prosthetic (should be 21137), or when frontal sinus setback was also done (should be 21139)
- Missing or insufficient prior authorization: many commercial plans require procedure-specific auth for craniofacial reconstruction; auth obtained for a related code does not transfer
- Global period conflict: a same-surgeon procedure billed during the 90-day global without the correct modifier (78, 79, or 24) is auto-bundled and denied
- Diagnosis-code mismatch: ICD-10 code submitted does not map to a covered indication under the payer's craniofacial or reconstructive surgery policy
Frequently asked questions
Source · Generated from the editorial pipeline, verified against 4 cited references ↓
01What is the difference between 21137, 21138, and 21139?
02Does Medicare cover 21138 for gender-affirming forehead feminization surgery?
03Can 21138 be billed on the same day as other craniofacial reconstruction codes?
04What global period applies to 21138 and what does it include?
05Is 21138 performed in an ASC or hospital outpatient setting, and does site of service affect payment?
06When should modifier 22 be appended to 21138?
Sources & references
Editorial content was developed using the following public sources. Last verified May 8, 2026.
Mira Scribe
The Mira AI Scribe captures the surgeon's dictation of forehead bone reduction technique, prosthetic type and material, implant fixation method, and confirmation that frontal sinus setback was not performed. That last detail directly separates 21138 from 21139 and prevents downcoding or upcoding flags during audit. The scribe also logs the preoperative diagnosis and any prior authorization reference, so the claim goes out with complete supporting context attached.
See how Mira captures CPT 21138 documentation