Open repair of an orbital floor blowout fracture using a transantral (Caldwell-Luc) approach, accessing the orbital floor through an incision inside the mouth via the maxillary sinus.

Verified May 8, 2026 · 7 sources ↓

Medicare: $674.36
Work RVU: 9.33
Global, days: 90
Region: Other

Drawn from CMSAAPCEmednyAAOSFindacode

Documentation requirements

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

Source · Editorial brief grounded in 7 cited references ↓

Explicitly name the surgical approach — 'transantral' or 'Caldwell-Luc' — in the operative note; 'standard approach' is an audit flag.
Document the incision site (intraoral, above upper teeth) and access through the anterior maxillary sinus wall.
Describe the fracture visualization, reduction technique, and any implant or graft material used and its source.
Confirm the laterality of the orbital floor fracture (left or right) to support LT/RT modifier use.
Record pre-operative imaging (CT orbit) confirming blowout fracture morphology and displacement.
Document medical necessity: diplopia, enophthalmos, symptomatic entrapment, or significant herniation of orbital contents.

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity 50 Bilateral procedure 51 Multiple procedures 52 Reduced services 58 Staged or related 62 Co-surgeons 74 Discontinued post-anesthesia 78 Unplanned return — related 79 Unrelated during global 80 Assistant surgeon LT Left side RT Right side

What this code covers

Source · Editorial summary grounded in 7 cited references ↓

CPT 21385 covers open surgical repair of an orbital floor blowout fracture when the surgeon uses a transantral approach — specifically a Caldwell-Luc type operation. The surgeon makes an incision inside the mouth above the upper teeth, opens the anterior wall of the maxillary sinus, and then visualizes and reduces the fractured orbital floor from below. Displaced bone fragments are repositioned, and synthetic material or autologous bone graft may be used to restore orbital floor integrity, though graft harvest is not included in 21385 — for that, select 21395 (periorbital approach with bone graft).

The transantral route distinguishes 21385 from its sibling codes: 21386 (periorbital approach), 21387 (combined approach), 21390 (periorbital with alloplastic implant), and 21395 (periorbital with bone graft). Payers and auditors will scrutinize operative notes to confirm the approach actually matches the code billed — defaulting to 21385 when a periorbital approach was used is a common audit trigger.

The code carries a 90-day global period. All routine post-op visits, wound checks, and suture removal through day 90 are bundled. An unrelated procedure performed during the global window requires modifier 79; a related return to the OR requires modifier 78. The day-before pre-op visit, if performed, is also included in the global.

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 (9.33) is the surgeon's own effort — the figure physician pay and productivity targets are built on. The total RVU (20.19) adds practice overhead and malpractice, and is what drives the Medicare payment below.

Work RVU	9.33
Practice expense RVU	9.13
Malpractice RVU	1.73
Total RVU	20.19
Medicare national rate	$674.36
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	$674.36
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 21385 get rejected.

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

Approach mismatch — billing 21385 (transantral) when the operative note describes a periorbital incision, which maps to 21386 or 21390.
Missing laterality modifier — payers, especially Medicare Advantage plans, routinely deny bilateral facial fracture claims lacking LT or RT.
Insufficient medical necessity documentation — no pre-op CT or clinical findings (diplopia, enophthalmos, entrapment) supporting open vs. closed treatment.
Global period conflict — E/M or minor procedure billed within the 90-day global without modifier 24 or 79 to indicate unrelatedness.
Bundling issue when co-billed with sinus procedure codes (e.g., 31256) — payers may bundle if documentation doesn't clearly separate the distinct surgical objectives.

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 7 cited references ↓

01What distinguishes 21385 from 21386 and 21387?

Approach is the only differentiator. 21385 is the transantral (Caldwell-Luc) route through the mouth and maxillary sinus. 21386 is a periorbital (eyelid/conjunctival) approach. 21387 is a combined use of both. The operative note must name the approach — payers will downcode or deny if it doesn't.

02Is bone graft harvest included in 21385?

No. 21385 does not include graft harvest. If a periorbital approach with autologous bone graft is used, report 21395 instead. Using 21385 when a graft was harvested undercodes the procedure.

03Can 21385 and a nasal/sinus procedure code be billed together on the same day?

Potentially, but carefully. The transantral approach involves the maxillary sinus, so payers may bundle a same-day antrostomy or sinus procedure unless documentation clearly separates the surgical objectives and anatomic work. Modifier 59 (or its X-modifier equivalents) requires genuine distinctness — different operative intent, not just different codes.

04What modifier is needed for a bilateral orbital floor repair performed in one session?

Modifier 50. Bilateral blowout fractures repaired in a single operative session — even through two separate transantral approaches — are reported with modifier 50 on 21385. Confirm your payer accepts modifier 50 vs. requiring two line items with LT and RT.

05How does the 90-day global period affect post-op ophthalmology or oculoplastics consults?

Consults or E/M services for complications directly related to the orbital repair are bundled in the global. An unrelated ophthalmologic condition (e.g., pre-existing glaucoma follow-up) billed within the 90-day global needs modifier 24 with clear documentation of unrelatedness.

06When is modifier 22 appropriate for 21385?

Modifier 22 applies when the procedure is substantially more complex than typical — for example, severely comminuted fractures, significant orbital fat or muscle entrapment requiring meticulous dissection, or unusually prolonged operative time. Document the specific factors that increased difficulty; without that, payers routinely ignore modifier 22 additions.

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 surgical approach by name (transantral/Caldwell-Luc), intraoral incision location, maxillary sinus entry, fracture visualization method, reduction technique, and any implant or graft material placed. It also flags laterality and records pre-op imaging findings referenced during dictation. This prevents the most common denial trigger for 21385: an operative note that omits the approach name, forcing auditors to default to a lower-paying or incorrect sibling code.

See how Mira captures CPT 21385 documentation