Open surgical repair of a LeFort III craniofacial separation that is complicated by comminution or cranial nerve foramina involvement, requiring multiple surgical approaches.

Verified May 8, 2026 · 6 sources ↓

Medicare: $1,526.42
Total RVUs: 45.7
Global, days: 90
Region: Other

Drawn from CMSGenhealthAAPCFindacodeAAOS

Documentation requirements

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

Source · Editorial brief grounded in 6 cited references ↓

Specify the fracture as LeFort III-type with documentation of complete craniofacial separation from the skull base
Document the complicating factor explicitly — comminution, cranial nerve foramina involvement, or both
Name each surgical approach used (e.g., coronal, subciliary, transconjunctival, intraoral) — do not write 'standard approach'
Record all fixation hardware applied, including plate size, screw count, and anatomic location
Document cranial nerve status pre- and intraoperatively, including any repair or decompression performed
Include pre-op imaging (CT with 3D reconstruction preferred) confirming LeFort III fracture pattern and complication features

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity 51 Multiple procedures 57 Decision for surgery 58 Staged or related 62 Co-surgeons 74 Discontinued post-anesthesia 78 Unplanned return — related 79 Unrelated during global 80 Assistant surgeon AS PA/NP/CNS assistant LT Left side RT Right side

What this code covers

Source · Editorial summary grounded in 6 cited references ↓

CPT 21433 covers open treatment of a LeFort III-type craniofacial separation — a complete disconnection of the midface from the skull base — when the fracture pattern is complicated (comminuted or involving cranial nerve foramina) and demands multiple surgical approaches. Surgeons reposition and rigidly fixate the displaced facial skeleton using plates, screws, or other hardware, with explicit attention to protecting or repairing cranial nerve pathways. This is not a routine facial fracture repair; the complexity designation drives both the code selection and the operative documentation standard.

The 90-day global period covers all routine post-op care through day 90. Any subsequent procedure for a complication — planned or unplanned — must be reported with the appropriate global-period modifier. Unplanned returns for a related complication use modifier 78; unrelated procedures in the same window use modifier 79. Assistant surgeon services are separately reportable with modifier 80 or AS for a PA/NP first assist, and are commonly justified given the multi-approach nature of this repair.

This code is billed almost exclusively in a hospital inpatient or outpatient setting. The HOPD and ASC payment rates differ materially — see the Site of Service comparison on this page. Given the high RVU weight and 90-day global, audit scrutiny is elevated. Operative notes that fail to document fracture complexity, specific approaches used, and cranial nerve involvement are the primary vector for downcoding or denial.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	25.63
Practice expense RVU	15.31
Malpractice RVU	4.76
Total RVU	45.7
Medicare national rate	$1,526.42
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	$1,526.42
HOPD (APC 5165) Hospital outpatient department	$6,048.05
ASC (PI J8) Ambulatory surgical center (freestanding)	$3,833.49

Common denial reasons

The recurring reasons claims for CPT 21433 get rejected.

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

Operative note lacks explicit documentation of complication (comminution or cranial nerve foramina involvement), triggering downcode to 21432
Failure to document multiple surgical approaches — single-approach documentation does not support 21433
Medical necessity denied when pre-op CT imaging confirming LeFort III pattern is absent from the record
Global period violations — post-op E&M or related procedure billed without modifier 24 or 78 during the 90-day window
Upcoding flags when 21433 is billed for fractures that imaging and the operative note describe as a simple or non-comminuted LeFort III pattern

Frequently asked questions

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

01What separates 21433 from 21432?

21432 covers open LeFort III repair via a single surgical approach without complicating factors. 21433 requires documentation of either comminution, cranial nerve foramina involvement, or both — plus the use of multiple surgical approaches. If the note doesn't establish both elements, you don't have 21433.

02Can modifier 22 be added for extraordinary complexity?

Yes, if the procedure required significantly more work than the code already captures — for example, extensive cranial nerve dissection or repair beyond typical foramina involvement. Document the additional time and complexity in the operative note and attach a cover letter. Expect payer review.

03Is an assistant surgeon billable with this code?

Yes. The multi-approach, high-complexity nature of this repair routinely justifies assistant surgeon billing. Report modifier 80 for an MD assistant or AS for a PA/NP first assist, subject to payer policy on mid-level first assists.

04What modifier applies if the patient returns to the OR during the 90-day global for a related complication?

Modifier 78 — unplanned return to the OR for a complication related to the original procedure. Do not use modifier 79 unless the return procedure is genuinely unrelated to the craniofacial repair.

05Does fluoroscopy or intraoperative imaging need to be billed separately?

No. Per NCCI policy, if the procedure code descriptor or CMS instruction indicates radiologic guidance is integral to the procedure, it cannot be reported separately. Review the operative note — if fluoroscopy was used solely to confirm reduction, separate billing is not supported.

06What ICD-10 diagnoses typically pair with 21433?

LeFort III fracture codes (S02.411–S02.413 range) with seventh-character designators for initial encounter (A or B for open/closed) are the primary pairings. Ensure the diagnosis code reflects fracture complexity — a simple nasal fracture code will trigger a mismatch denial against 21433.

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 fracture classification (LeFort III), the specific complicating factors (comminution, cranial nerve foramina involvement), each named surgical approach, fixation hardware details, and cranial nerve status from surgeon dictation. That prevents the most common downcode trigger: operative notes that confirm a craniofacial separation but fail to document the complexity elements that distinguish 21433 from 21432.

See how Mira captures CPT 21433 documentation