CPT code 21387: Orbital blowout fracture, combined approach

Key takeaways

CPT code 21387 covers open treatment of an orbital floor blowout fracture through a combined approach, using periorbital and transantral access together.

Approach separates 21385, 21386, and 21387. Implant and graft placement separate 21390 and 21395.

A repair done through one periorbital incision codes to 21386, so the operative note has to name every access route used.

Pair the claim with a laterality-specific diagnosis such as S02.31XA. The old S02.3XXA family was deleted on October 1, 2016.

Practice management software like Pabau keeps claims and clinical records in one system, so what you submit matches what you documented.

CPT code 21387 covers open treatment of an orbital floor blowout fracture through a combined approach. The surgeon reaches the fracture by two routes in the same session: a periorbital incision and a transantral window through the maxillary sinus.

The code is often described as the “without implant” version of 21386. That is wrong, and it is an expensive mistake. Implant status never appears in the 21387 descriptor.

This reference covers the correct descriptor, the 21385 to 21395 family, ICD-10 pairings, modifiers, reimbursement, and the operative note wording that supports the claim.

CPT code 21387: Definition and clinical description

CPT code 21387 sits in the Fracture and/or Dislocation Procedures on the Head section of the AMA’s CPT code set. It is an indented child code, so its short descriptor only makes sense when you read it with the parent stem at 21385.

One element decides this code, and it is the access route. Nothing in the descriptor refers to an implant, a graft, or fixation hardware. If the note describes one incision, 21387 is the wrong code.

Procedure description: What 21387 covers

An orbital floor blowout fracture happens when blunt trauma to the orbit drives the thin bony floor down toward the maxillary sinus. Orbital fat or the inferior rectus muscle can herniate through the defect. That produces diplopia, enophthalmos, or hypoglobus, and it is what makes open repair necessary.

Blowout fractures usually follow assault, a fall, or a sports impact. The CT often arrives with the patient from an emergency department or a sports medicine practice. Attach that report to the surgical record, because the claim leans on it for medical necessity.

A combined repair uses two windows onto the same fracture. The periorbital incision gives the surgeon a direct view of the orbital rim and floor from above. The transantral route opens the maxillary sinus from below, so the surgeon can support the floor and confirm the reduction from the antral side.

The work covered by a single 21387 line includes:

• The periorbital incision, usually transconjunctival or subciliary, to expose the orbital floor
• The transantral (Caldwell-Luc) antrostomy to reach the floor from beneath
• Release and reduction of herniated orbital fat or extraocular muscle back into the orbit
• Repositioning and support of the fractured floor fragments
• Irrigation, hemostasis, and layered closure of both access sites

Both approaches sit inside this one code. Reporting 21385 and 21386 together for the same repair is unbundling, and payers deny it on National Correct Coding Initiative edits.

Clinical indications: When to use 21387

Surgeons reach for a combined approach when one window will not do the job. The clinical picture, not the coder, decides that. These are the scenarios that usually justify it.

• A large or posterior defect: the fracture extends beyond the reach of a transconjunctival view alone
• Comminution: multiple floor fragments need support from below while they are held in position
• Trapped tissue: incarcerated muscle or fat that will not release from the orbital side alone
• Concurrent maxillary sinus disease or fracture: the antrum has to be entered anyway
• Uncertain reduction: the surgeon wants to confirm floor position from the antral side before closing

If the surgeon planned a combined approach and then completed the repair through the eyelid alone, bill 21386. The code follows what was done, not what was scheduled.

Related CPT codes: 21385, 21386, 21390, and 21395

Five codes cover open repair of an orbital floor blowout fracture. Three of them are separated by access route, and two by what the surgeon places in the orbit. Mixing those two axes is the single most common error on these claims.

Notice what the family does not contain. There is no code for a combined approach with an implant, and no code for a transantral approach with a graft. That absence is where most 21387 disputes start.

CPT 21387 vs CPT 21386: The key difference

The difference is the number of access routes, not implant status. CPT 21386 covers a repair done entirely through a periorbital incision, whether that is transconjunctival or subciliary. CPT 21387 covers the same fracture reached through a periorbital incision plus a transantral window.

Plenty of coding write-ups still describe 21386 as “with implant” and 21387 as “without implant”. No AMA descriptor has ever read that way. A claim built on those summaries will not survive a records request.

So the operative note has to name every incision. A note that says “the orbital floor was exposed and the fracture reduced” supports neither code. For plastic surgery software users, an operative template with a required approach field settles this at the point of documentation.

CPT 21387 vs CPT 21390 and 21395

CPT 21390 and CPT 21395 both describe a periorbital approach. What sets them apart is reconstruction material.

CPT 21390 applies when the surgeon places an alloplastic or other implant, such as titanium mesh or porous polyethylene. CPT 21395 applies when the surgeon places a bone graft, and the descriptor already includes harvesting that graft.

Do not bill a separate graft harvest code alongside 21395. The harvest is bundled into the descriptor, and billing it again is a straightforward unbundling denial.

The awkward case is a combined approach that also uses an implant. No single code describes it. Most payers expect the implant code, with an operative note that documents both access routes, and some coders append modifier -22 for the added work.

Confirm the expectation with the payer before you submit, because there is no national rule here. For implant-based repair of orbital fractures outside the blowout family, see CPT code 21407.

ICD-10 diagnosis codes linked to CPT code 21387

Every CPT 21387 claim needs a paired ICD-10-CM code that establishes medical necessity. Orbital floor fracture codes became laterality-specific on October 1, 2016. The old non-lateral codes S02.3XXA, S02.3XXB, and S02.3XXD were deleted at that point and no longer pass a claim edit.

Current codes carry a laterality digit and then a seventh character for the encounter. S02.30X- is the unspecified side, S02.31X- is the right, and S02.32X- is the left.

Two errors account for most diagnosis-side rejections on these claims. The first is a deleted S02.3XXA code copied from an old superbill or an outdated coding article.

The second is a seventh character that does not match the visit, such as “D” on the initial surgical claim. Fracture codes across ICD-10 follow the same convention, as S42.302K shows.

Medial orbital wall fracture is worth its own mention. It is not a variant of the floor code, and S02.31XA does not mean medial wall. That fracture belongs to S02.83-, and mislabeling it is a common source of confusion in orbital trauma coding.

Payer policy varies on top of all this. Some Medicare Administrative Contractors publish Local Coverage Determinations naming which diagnosis codes they accept for orbital fracture repair.

Check the applicable LCD before submitting, and see ICD-10 code S02.32XB for how the laterality and encounter characters work on a single orbital floor code.

Applicable modifiers for CPT code 21387

Modifier selection for CPT 21387 depends on payer rules and the operative scenario. Bilateral blowout fracture repair in one session is uncommon, but it does happen. Verify bilateral policy with the applicable MAC first, because contractors differ on modifier 50 versus separate LT and RT lines.

Modifier 62 deserves a note of its own. Some combined repairs are staffed by two surgeons, with an ENT surgeon taking the transantral route and an oculoplastic surgeon the periorbital one.

Where both act as co-surgeons on the same 21387 line, each reports the code with modifier 62. Check the CMS co-surgeon indicator for the code before you plan the claim that way.

Medicare reimbursement and fee schedule for CPT code 21387

Medicare pays CPT 21387 from the CMS Medicare Physician Fee Schedule, which updates every January 1. The figures below reflect recently published national values. Treat them as a planning baseline, not a quote.

Two things move that number. The conversion factor changes every year, and Geographic Practice Cost Indices adjust each RVU component by locality. A surgeon in Manhattan and one in rural Kansas will not see the same payment for the same operation.

Because 21387 is the combined-approach code, it carries more work value than the single-approach codes around it. That is the practical reason payers scrutinize the approach documentation on these claims.

Pull current values from the CMS Look-Up Tool before you set contracted rates, and check the payment rules in our Medicare billing guide.

Documentation requirements for CPT code 21387

A clean CPT 21387 claim rests on four elements in the operative note. Miss any one of them and a payer has grounds to deny on medical necessity or code specificity.

• Both access routes, named: state the periorbital incision by type, transconjunctival or subciliary, and state the transantral antrostomy separately. This is what separates 21387 from 21386 and 21385.
• Fracture confirmation: record the CT findings for the orbital floor defect and the clinical correlation, such as diplopia, enophthalmos, or restricted extraocular movement.
• Reduction of herniated tissue: describe the orbital fat or muscle that was released and returned to the orbit. This supports the need for open surgery.
• What was placed, if anything: note any implant or graft. It does not change the 21387 descriptor, but it decides whether 21390 or 21395 is the better fit.

Laterality belongs in the note too. The side has to agree across the operative report, the diagnosis code, and any LT or RT modifier on the claim line.

Practices running a plastic surgery EMR can build these four checkpoints in as structured fields, so they are captured before the note is signed. The same medical forms management discipline that works for consents applies here. A standard structure produces audit-ready records.

Common billing errors and claim denials

These are the failure patterns that show up when a 21387 claim reaches post-payment review. Most of them are settled long before submission, in the operative note.

• Coding from the implant myth: choosing 21387 because no implant was placed. Implant status is irrelevant to this code, and a single-approach repair belongs on 21386.
• Unbundling the approaches: billing 21385 and 21386 on the same claim instead of the single combined code.
• A deleted diagnosis code: submitting S02.3XXA, S02.3XXB, or S02.3XXD, which have not been valid since October 1, 2016.
• A mislabeled medial wall code: treating S02.31XA as a medial orbital wall fracture. It is the right-sided orbital floor code, and the medial wall lives at S02.83-.
• The wrong seventh character: using “D” or “S” on the initial surgical claim.
• A vague approach description: an operative note that says the floor was exposed, without naming the incisions.
• Global period violations: billing a related post-operative service inside the 90-day window with no modifier.
• A missing narrative for -22: appending the modifier without explaining what made the case harder than the 21387 baseline.

Coding guidance from the AAPC code range lookup also carries a warning about concurrent procedures. Do not report the 21385 to 21395 series alongside a separately reportable procedure unless distinct documentation supports it. Review NCCI edits before pairing 21387 with other facial fracture codes such as CPT code 21452.

Billing 21387 in ASC vs hospital settings

CPT 21387 is performed in hospital and ambulatory surgical center settings alike. The billing mechanics differ by setting, and the split between the professional and facility fee is where claims go wrong.

In a hospital, the surgeon bills the professional fee under the MPFS. The hospital bills the facility fee separately under the Hospital Outpatient Prospective Payment System, using an Ambulatory Payment Classification rate. The surgeon does not bill the facility component at all.

In an ASC, the surgeon again bills the professional fee under the MPFS. The ASC bills its facility fee under the CMS ASC payment system. ASC facility rates run lower than HOPPS rates, though the setting usually carries lower overhead for the practice.

The place of service code has to match where the surgery actually happened. Submitting POS 22 for an ASC case, or the reverse, applies the wrong practice expense RVU and triggers a claim edit. Practices weighing the two settings can start with our guide to opening a cosmetic surgery practice.

Anesthesia codes paired with CPT 21387

A combined orbital floor repair is done under general anesthesia. The anesthesia provider bills from the 00100 to 01999 range, not from 21387. The surgeon’s billing team does not submit that code.

The two records still need to tell the same story. If the anesthesia record describes a simpler operation than the surgical note, a payer can question both claims. That risk rises with 21387, because the combined approach is exactly what justifies its higher work value.

How Pabau keeps 21387 claims matched to the operative note

In most surgical practices the operative note lives in one system and the claim is built in another. Someone reads the note, retypes the codes into a billing tool, and hopes the two still agree at audit.

Practice management software like Pabau keeps both in one record. The patient’s insurer and policy sit on their chart, so every invoice routes to the right payer without re-keying. Claims management submits electronically, tracks each claim through submitted, processing, paid, or error, and posts the remittance back against the invoice.

Validation runs before anything leaves the practice. A missing membership number or authorization code stops the send, rather than coming back weeks later as a rejection.

Structured forms hold the detail a 21387 note needs: each incision, the laterality, and whether an implant or graft was placed. Your team spends its time on the surgery schedule instead of reworking denials.

Keep every surgical claim tied to its clinical record

Pabau brings claims, invoices, and clinical records into one system. Submit electronically, watch every claim’s status, and fix missing details before a payer rejects them.

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Conclusion

CPT 21387 is the combined-approach code, and nothing more. A reviewer opens the operative note looking for two access routes, and either finds them named or does not. Implant status has no bearing on that decision.

So write the note for that reader. Name the periorbital incision, name the antrostomy, name the side, and pair the claim with a current laterality-specific diagnosis code. Do that and 21387 stops being a code you defend after payment.

Fixing this while the note is still open costs a few extra lines. Fixing it at appeal costs weeks. Book a demo to see how Pabau keeps surgical claims and clinical records in step.

Continue your research

Reconstructing the orbital wall rather than reducing a fracture? CPT code 21184 walks through orbital wall reconstruction billing and its documentation.

Coding another facial fracture repair? CPT code 21365 covers complicated malar fractures, their modifiers, and their reimbursement.

Billing a midface fracture repair? CPT code 21422 covers open treatment of a palatal or maxillary fracture, with its modifiers and documentation.

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