Significant changes are coming to CPT® coding for minimally invasive sacroiliac (SI) joint fusion. As new implant designs and techniques have entered the market, coders have struggled to match procedures to the correct CPT® codes. After years of discussion, the AMA CPT® Editorial Panel finalized new guidance and revised descriptors at the May 2025 meeting, which will take effect January 1, 2026.

This rewrite will help you clearly understand implant types, procedural techniques, and how to properly assign 27278 vs 27279 beginning in 2026.

1. Why the Codes Changed

Since 2015, minimally invasive SI joint fusion has expanded beyond the traditional lateral transarticular (transfixing) approach. Newer devices—especially intra-articular systems—created confusion because old code language didn’t fit newer techniques.

To fix this, the AMA:

• Updated the code descriptors for 27278 and 27279

• Added anatomical and procedural terms (cortex, pierce, intra-articular vs transarticular)

• Clarified how hybrid procedures are coded

2. Updated Code Descriptors (Effective 1/1/2026)

27278 – Intra-articular device(s) WITHOUT cortical piercing

Key points:

• Devices stay entirely inside the SI joint space

• Device does NOT pierce the ilium or sacrum cortices

• No transfixation across the joint

• Includes image guidance and grafting when performed

27279 – Intra-articular and/or transarticular device(s) WITH cortical piercing

Key points:

• Device pierces lateral or medial cortex of the ilium

• AND pierces the lateral cortex of the sacrum

• Can include transarticular devices, or intra-articular devices with built-in fixation (e.g., blades, screws, flanges) that pierce cortices

• Used for hybrid procedures when at least one device pierces cortices

3. Key Terms Coders Must Know

These terms appear in the revised code descriptors:

4. The New CPT® Guideline for 2026

Use 27278
→ For intra-articular devices that do not pierce either the ilium or sacrum cortices.

Use 27279
→ For devices that pierce any required cortex
→ For any transarticular placement
→ For hybrid constructs where at least one device pierces cortical bone

5. What Coders MUST Review

To code SI joint fusion correctly, review:

1. Implant material (titanium, allograft, cage, wedge, etc.)

2. Indications for Use (from FDA/manufacturer)

3. Operative note details:

   • Does the device stay inside the joint?

   • Does it pierce cortical bone?

   • Does it cross from ilium to sacrum?

   • Is fixation intrinsic, such as blades/screws integrated into the implant?

These details determine 27278 vs 27279.

6. Implant Types and How They Map to Codes

Report 27279 When:

• The device crosses the SI joint (transarticular)

• A guide pin, drill, or implant enters ilium → sacrum

• The device has built-in fixation (e.g., screws, blades, flanges) that pierce bone

• The surgeon uses a lateral transarticular approach

• Any implant in a hybrid construct pierces dense cortex

  FREE CPT Code Search Tool (Click Here)

  

  MUST BUY CPT & ICD-10 CM  CODING EBOOKS 

Report 27278 When:

• Device stays entirely inside the joint space

• No cortical bone is pierced

• Implant acts as an intra-articular spacer, cage, wedge, or allograft

• The purpose is joint distraction and stabilization without transfixation

7. Coding Scenarios (Simplified for Coders)

Scenario 1: 27279

Procedure: Titanium triangular implant(s) placed from ilium → sacrum (traditional lateral transarticular technique).

Coding rationale:

• Implants pierce ilium and sacrum cortices

• Guide pin and implants cross the SI joint

• Uses transarticular fixation

✅ Correct code: 27279

Scenario 2: 27278

Procedure: Rectangular titanium intra-articular cage placed entirely within the SI joint; no cortical breach.

Coding rationale:

• Device remains inside the joint space

• Does not pierce ilium or sacrum

• No transfixation across the joint

✅ Correct code: 27278

8. 2026 Key Takeaway for Coders

Know the device. Know how it is implanted. Know whether cortices are pierced.

To code SI joint fusion accurately:

• Study your provider’s preferred SI joint systems

• Look up FDA indications and manufacturer details

• Identify exactly where the implant sits and whether it pierces bone

Correct assignment of 27278 vs 27279 depends entirely on implant behavior and surgical technique, not marketing terms like “transfixing” or “stabilizing.”