Closure of a median sternotomy separation, with or without debridement of the wound — billed as a separate procedure.

Verified May 8, 2026 · 6 sources ↓

Medicare: $660.67
Total RVUs: 19.78
Global, days: 90
Region: Other

Drawn from CMSFastrvuAAPC

Documentation requirements

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

Source · Editorial brief grounded in 6 cited references ↓

Operative note must identify the prior procedure that created the median sternotomy (e.g., CABG, valve repair) and the clinical basis for dehiscence
Document whether debridement was performed and describe the extent — viable vs. necrotic tissue, depth of involvement
Specify the fixation method used for sternal re-approximation (e.g., stainless steel wire, rigid plate system)
Record wound cultures or infectious workup results if dehiscence was associated with sternal wound infection
Surgeon's note must confirm this was a distinct, separate operative encounter — not simply wound care — to support the 'separate procedure' designation
Document assistant surgeon participation and role if modifier 80 or AS is appended

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity 51 Multiple procedures 52 Reduced services 24 Unrelated E/M during global 25 Significant separate E/M 78 Unplanned return — related 79 Unrelated during global 80 Assistant surgeon AS PA/NP/CNS assistant 58 Staged or related

What this code covers

Source · Editorial summary grounded in 6 cited references ↓

CPT 21750 covers surgical closure of a median sternotomy dehiscence — the separation of the sternum along a prior midline incision, most commonly following open cardiac or thoracic surgery. The procedure involves re-approximating the sternum with wire or rigid fixation, and may include debridement of devitalized tissue when infection or necrosis is present. Debridement is not separately billable when performed as part of this closure.

The code carries a 90-day global period. Any E/M services related to the sternal wound or the repair itself are bundled through that window. If a separately identifiable E/M is documented for an unrelated problem during the global period, append modifier 24. A return to the OR for an unrelated procedure in the post-op window requires modifier 79; a related return for a complication of the repair requires modifier 78 — don't invert these.

CMS designates 21750 as an inpatient-only (IPO) procedure under OPPS. It cannot be billed in a hospital outpatient or ASC setting for Medicare patients — the procedure must be performed in an inpatient hospital. Coding teams should align place of service accordingly and confirm payer-specific site-of-service rules for non-Medicare payers before submission.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	11.12
Practice expense RVU	5.93
Malpractice RVU	2.73
Total RVU	19.78
Medicare national rate	$660.67
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	$660.67
HOPD (APC 5114) Hospital outpatient department	$7,413.38
ASC (PI J8) Ambulatory surgical center (freestanding)	$4,682.29

Common denial reasons

The recurring reasons claims for CPT 21750 get rejected.

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

Billed in outpatient hospital or ASC setting — 21750 is Medicare inpatient-only (IPO) and will deny under OPPS
Global period conflict — post-op E/M visits for the sternal repair billed without modifier 24 or 25 within the 90-day window
Missing or insufficient operative documentation to distinguish surgical closure from bedside wound care
Modifier 78 and 79 confusion on return-to-OR claims — unrelated return incorrectly coded as 78 triggers bundling denial
Debridement billed separately on the same date — debridement is included when performed as part of the closure

Frequently asked questions

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

01Is CPT 21750 payable in an ASC or hospital outpatient setting for Medicare patients?

No. CMS designates 21750 as an inpatient-only (IPO) procedure. It is not covered under OPPS or in ASCs for Medicare. The procedure must be performed in an inpatient hospital setting to be reimbursed by Medicare.

02Can I bill debridement separately when it's performed at the same time as sternal closure?

No. Debridement performed as part of the median sternotomy closure is included in 21750 and is not separately reportable on the same date of service.

03What modifier applies if the patient returns to the OR for sternal re-closure during the 90-day global of the original cardiac surgery?

Use modifier 78 if the return is directly related to a complication of the prior procedure, or modifier 79 if the sternal repair is unrelated. The distinction matters — 78 reimburses at the intraoperative component only, while 79 opens a new global period.

04How do I bill for an assistant surgeon on this case?

Append modifier 80 for an MD assistant or modifier AS for a PA, NP, or CNS assisting at surgery. Document the assistant's medical necessity in the operative note — complex sternal anatomy or infectious involvement typically supports the need.

05Is a separate E/M billable on the same day as 21750 for pre-operative evaluation?

Only if it's a significant, separately identifiable service for a problem unrelated to the sternal repair decision. The decision to perform the surgery is bundled into the procedure. If a distinct E/M is warranted, append modifier 25 and document the separate problem clearly.

06Does modifier 22 apply when the sternal dehiscence involves deep infection or extensive debridement?

Yes, modifier 22 can apply when the procedure required substantially greater effort than typical — such as management of osteomyelitis, infected hardware removal, or complex soft tissue reconstruction alongside closure. Include a cover letter with operative note detail quantifying the added complexity to support the increased payment request.

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 indication for return to OR (dehiscence onset, clinical signs of infection or mechanical failure), fixation technique, debridement extent, wound culture status, and the identity of the original sternotomy procedure. That documentation chain prevents the most common denial pattern for 21750: a claim that looks like duplicative wound care rather than a distinct surgical closure, and supports medical necessity when payers audit IPO claims.

See how Mira captures CPT 21750 documentation