Open surgical repair of seven or more unilateral rib fractures with internal fixation hardware; thoracoscopic visualization is included when performed.

Verified May 8, 2026 · 6 sources ↓

Medicare: $891.47
Work RVU: 17.17
Global, days: 0
Region: Other

Drawn from AAPCCMSGenhealth

Documentation requirements

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

Source · Editorial brief grounded in 6 cited references ↓

Exact count and identification of ribs treated with internal fixation (e.g., ribs 4–10 left side)
Type of internal fixation hardware used (plates, screws, nails, wires, or rib-specific plating system)
Whether thoracoscopic visualization was performed — document as included, not as a separate procedure
Operative note specifying open surgical approach, not closed or external fixation
Laterality documented clearly — unilateral vs. bilateral determines whether modifier 50 is required
Clinical indication supporting surgical intervention (flail chest, respiratory compromise, fracture instability, failed conservative management)

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 59 Distinct service 76 Repeat, same physician 77 Repeat, another physician 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 21813 covers open treatment of seven or more ribs on one side using internal fixation — plates, screws, nails, or wires applied to stabilize the fracture and restore chest wall mechanics. Internal fixation is required by the code descriptor (no comma separates it from the procedure description). Thoracoscopic visualization, when used for better surgical access, is bundled into 21813 and cannot be billed separately. Intraoperative fluoroscopy or X-rays are also part of the surgical package and are not separately reportable by the operating surgeon.

21813 is the highest-acuity code in the 21811–21813 family, which stratifies open rib fixation by rib count: 1–3 ribs (21811), 4–6 ribs (21812), and 7 or more ribs (21813). All three are unilateral codes. If the surgeon fixates seven or more ribs on both sides in a single session, append modifier 50 to 21813. The code carries a 000-day global period, meaning post-op E/M visits are separately billable from the day of surgery forward — the 90-day global framework discussed in some sources applies only when payers treat open fracture care under that convention, so verify with the specific payer.

Primary indications include flail chest, unstable multi-rib fractures causing respiratory compromise, and fracture patterns that have failed or would predictably fail conservative management. The procedure is hospital-based; there is no ASC payment established. Coding the correct rib count is the single most important accuracy factor — operative notes must enumerate each rib treated with fixation.

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 (17.17) is the surgeon's own effort — the figure physician pay and productivity targets are built on. The total RVU (26.69) adds practice overhead and malpractice, and is what drives the Medicare payment below.

Work RVU	17.17
Practice expense RVU	4.92
Malpractice RVU	4.6
Total RVU	26.69
Medicare national rate	$891.47
Global period	0 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	$891.47
HOPD (APC 5112) Hospital outpatient department	$1,642.82

Common denial reasons

The recurring reasons claims for CPT 21813 get rejected.

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

Rib count underdocumented — operative note lists injury pattern but does not enumerate how many ribs received hardware
Thoracoscopic visualization billed separately (21813 includes it; unbundling triggers NCCI edit denial)
Bilateral procedure performed but modifier 50 omitted — payer pays only one side
Intraoperative X-rays billed separately by the operating surgeon — these are bundled into the surgical package
Selecting 21811 or 21812 when the operative note supports 7+ ribs, leaving significant RVU value on the table and risking downcoding on audit

Frequently asked questions

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

01Is thoracoscopic visualization separately billable when performed with 21813?

No. The code descriptor explicitly bundles thoracoscopic visualization when performed. Billing it separately triggers an NCCI edit. Document it in the operative note as included in the procedure.

02What modifier do I use when the surgeon fixes 7+ ribs on both sides in the same session?

Append modifier 50 to 21813. These codes are unilateral by design. One line with modifier 50 covers the bilateral case; reimbursement is typically capped at 150% of the single-side allowable.

03Is internal fixation hardware required to bill 21813, or can I use it for open reduction without hardware?

Internal fixation is required. The descriptor reads 'with internal fixation' without a separating comma, which coding guidance interprets as a mandatory element. Open treatment without hardware should be evaluated for unlisted code 21899.

04What is the global period for 21813, and can I bill post-op E/M visits separately?

21813 carries a 000-day global period. Post-op E/M services are separately billable starting the day of surgery. Confirm whether your payer treats this as a 90-day fracture-care global — some do — and apply modifiers 24 or 25 as needed.

05Can 21813 be performed in an ASC?

No ASC payment rate is established for 21813. This procedure is performed in a hospital operating room setting.

06How do I code bilateral rib fixation where one side has 4 ribs treated and the other has 7?

Each side is coded by its own rib count. Bill 21812 with modifier LT (or RT) for the 4-rib side and 21813 with the appropriate side modifier for the 7-rib side. Do not use modifier 50 when the two sides land in different code tiers.

07Are intraoperative X-rays billable separately by the operating surgeon?

No. Intraoperative imaging is part of the surgical package for 21813 and cannot be billed separately by the surgeon performing the fixation.

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 rib-by-rib enumeration from dictation — identifying each rib treated with internal fixation, the hardware type, laterality, and whether thoracoscopic visualization was used. That specificity locks in the correct code tier (21811 vs. 21812 vs. 21813) and eliminates the most common audit flag: an operative note that describes the injury pattern but never confirms how many ribs actually received fixation.

See how Mira captures CPT 21813 documentation