Fusion · Spine

Minimally invasive arthrodesis of the sacroiliac joint using a transfixing implant device placed percutaneously across the joint.

Verified May 8, 2026 · 7 sources ↓

Medicare: $758.53
Total RVUs: 22.71
Global, days: 90
Region: Spine

Drawn from CMSNoridianAAPCAssets

Documentation requirements

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

Source · Editorial brief grounded in 7 cited references ↓

Operative note must specify that a transfixing implant device was placed across the sacroiliac joint — not simply that fusion was performed.
Document the specific implant name, manufacturer, and number of implants placed to support medical necessity and implant traceability.
Preoperative imaging (CT or MRI) confirming SI joint pathology as the pain generator, correlated with physical exam findings and provocative SI joint tests.
Conservative treatment failure documented over an appropriate duration per the applicable MAC LCD requirements (commonly 6+ months of non-operative care).
If hybrid approach billed with 27278+51, operative note must explicitly justify the combined approach — e.g., sacral dysmorphism, bone deficit, revision strategy — not just describe the technique.
Laterality must be specified (left, right, or bilateral) in the operative note and on the claim.

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 78 Unplanned return — related 79 Unrelated during global LT Left side RT Right side

What this code covers

Source · Editorial summary grounded in 7 cited references ↓

CPT 27279 covers minimally invasive sacroiliac joint fusion performed with a transfixing device — hardware that crosses and immobilizes the SI joint itself. The transfixing requirement is the defining distinction between 27279 and its companion code 27278; both codes describe percutaneous MIS SIJ arthrodesis, but 27278 is used when no transfixing implant is placed. The code has been active as a Category I code since 2015 and underwent descriptor refinements in 2022, 2023, and again effective January 1, 2025 to clarify the transfixing definition — the code number itself has not changed.

The 90-day global period applies. All routine post-op visits through day 90 are bundled. Anything unrelated to the SI fusion billed during that window needs modifier 24 (E/M) or 79 (unrelated procedure). If a hybrid approach is used — transfixing implant plus a non-transfixing adjunct — ISASS guidance supports billing 27279 as the primary code and 27278 with modifier 51, provided the operative note clearly documents the medical necessity for the combined approach (e.g., sacral dysmorphism, insufficient bone stock, bony defect).

Coverage is governed by MAC-level LCDs. Multiple MACs have open or finalized LCDs for MIS SIJ fusion, and ICD-10 diagnosis codes that support medical necessity have been updated as recently as February 2025 (A57596 R6). Payer coverage status for 27279 is generally more established than for 27278, but MAC policies vary — verify the applicable LCD before billing.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	11.83
Practice expense RVU	8.26
Malpractice RVU	2.62
Total RVU	22.71
Medicare national rate	$758.53
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	$758.53
HOPD (APC 5116) Hospital outpatient department	$17,913.59
ASC (PI J8) Ambulatory surgical center (freestanding)	$14,517.56

Common denial reasons

The recurring reasons claims for CPT 27279 get rejected.

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

Operative note does not confirm a transfixing device was used, making the procedure indistinguishable from 27278.
ICD-10 diagnosis code not on the MAC LCD's covered diagnosis list — check the A57596 article for the current supported code set, last updated February 2025.
Insufficient documentation of conservative treatment failure prior to surgery, failing LCD medical necessity criteria.
Laterality modifier (LT/RT) missing or mismatched between claim and operative note.
27278 billed same-day without modifier 51 and without operative note justification for the hybrid approach, triggering NCCI bundling edit.
Global period violation — post-op visit billed without modifier 24 or 79 within the 90-day window.

Frequently asked questions

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

01What is the difference between CPT 27279 and 27278?

The only procedural distinction is the transfixing device. 27279 requires placement of an implant that transfixes — crosses — the SI joint. 27278, introduced as a Category I code in 2024, covers MIS SIJ fusion without a transfixing implant. All other components of the procedural descriptions are the same.

02Can 27279 and 27278 be billed together on the same case?

Yes, in documented hybrid cases. Bill 27279 as primary and 27278 with modifier 51. The operative note must explicitly justify the combined approach — sacral dysmorphism, insufficient bone stock, bony defect, or revision strategy are examples that have been cited by ISASS and acknowledged in CMS LCD comments.

03What modifiers are needed for bilateral SI joint fusion?

Modifier 50 for bilateral performed in the same session, or bill two line items with LT and RT. Confirm which format your payer accepts — Medicare and most commercial payers accept modifier 50, but some MACs or commercial contracts require separate LT/RT lines.

04What is the global period for 27279?

90 days. Routine post-op visits, dressing changes, and standard follow-up are bundled through day 90. An unrelated E/M during that window needs modifier 24; an unrelated surgical procedure needs modifier 79. A return to the OR for a complication related to the SI fusion uses modifier 78.

05Which diagnosis codes support medical necessity for 27279?

Coverage is LCD-driven and payer-specific. CMS billing and coding article A57596 (last revised February 2025) lists the current ICD-10 codes that support medical necessity, including recently added codes for sacroiliac joint disorders and related sacral injury sequelae. Pull the applicable MAC's LCD before billing to confirm your diagnosis code is on the covered list.

06Does modifier 22 apply to more complex SI joint fusion cases?

Yes, when the procedure required substantially greater work than typical — for example, revision cases, significant anatomic anomaly, or extensive scarring. Attach a cover letter to the claim documenting the added complexity. Modifier 22 without supporting documentation is a common audit flag.

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 implant name and transfixing confirmation directly from dictation, along with laterality, implant count, and the surgeon's documented rationale for the approach. This prevents the most common 27279 denial: an operative note that describes SI joint fusion without clearly establishing that a transfixing device crossed the joint — the detail that separates 27279 from 27278 on audit.

See how Mira captures CPT 27279 documentation