At a recent ASCA industry focus group, experts weighed in on the topic of coding and reimbursement for today’s minimally invasive sacroiliac joint (SI joint) procedures. SI joint procedures include two distinct types: one type that uses laterally placed transfixing devices via a transiliac approach (crossing the joint), and another that uses intra-articular placement of bone allograft products or devices typically placed via a posterior, or “dorsal,” approach (within the joint). Medicare data shared with the focus group on the current site of service mix for procedures coded under CPT code 27279* reveals a significant shift to ASCs has been occurring since 2018.

Pioneering SI joint fusion procedures

In 2009, a minimally invasive SI joint fusion procedure was introduced to U.S. patients (the iFuse Procedure, SI-BONE, Inc.), performed by orthopedic surgeons and neurosurgeons. Each year, iFuse implants are used in more than 7,000 SI joint procedures performed in the U.S., and have been used in over 65,000 procedures worldwide as of January 2022. iFuse implants are placed via a lateral, transiliac trajectory that places implants through the ilium bone, across the SI joint, and into the sacrum.

Today, an entire market is driven by a single CPT code

In 2015, CPT code 27279 was added by the AMA to describe procedures, like the iFuse Procedure, which use a “transfixing device” and a lateral, transiliac approach, where implants traverse three cortices of bone (“across the ilium, across the SI joint, and into the sacrum”). The AMA has since clarified this point further and stated that appropriate use of CPT 27279 requires a lateral, transiliac approach to transfix the joint.

SI joint procedural market data shows ~12,000 SI joint procedures are performed in hospitals and ASCs each year, the majority being reported as CPT 27279, “Arthrodesis, sacroiliac joint, percutaneous or minimally invasive (indirect visualization), with image guidance, includes obtaining bone graft when performed, and placement of transfixing device.”

Today, there are more than 30 metallic devices marketed in the U.S. that use a lateral, transiliac “transfixing device” approach, with either a lateral trajectory like the iFuse Procedure (crossing the joint, e.g., depiction (A) in the graphic below), or a posterolateral trajectory like the Rialto procedure (Medtronic) (e.g., depicted in (B) below). These procedures are typically coded under CPT code 27279 (“…placement of a transfixing device”).

Lateral transiliac transfixing devices. (A) Typical lateral transiliac trajectory. (B) Posterolateral transiliac trajectory.

Should newer SI joint procedures use CPT 27279, too?

Since 2018, a more novel SI joint procedure, with a different stabilization strategy, has been performed in ASCs with increasing popularity. The newer procedure intends to place an “interpositional” or “intraarticular” device or structural bone graft product from a posterior or “dorsal” approach, within the posterior ligamentous SI joint. E.g., CornerLoc (Foundation Fusion Solutions), LinQ (PainTEQ), SiLO (Aurora Spine), SIrten (Genesys Spine), PsiF (Omnia Medical). In this procedure, the implant does not cross or transfix the SI joint in a transiliac trajectory, but instead is placed within the joint.

Position of minimally invasive surgical intraarticular/“dorsal” products.

(c) 2019 International Society for the Advancement of Spine Surgery. Lorio MP. Editor's Introduction: Update on Current Sacroiliac Joint Fusion Procedures: Implications for Appropriate Current Procedural Terminology Medical Coding. Int J Spine Surg. 2020;13(2):853-859. doi:10.14444/7136. Reprinted with permission.

The AMA advises coders that CPT 27279 should not be used for these newer procedures. The AMA has confirmed that CPT 27279 was only intended to describe lateral, transiliac procedures (resulting in a transfixation of the joint). In June 2022, the CPT Editorial Panel posted its decision to add a Category III code (Cat III code or “t-code”) to describe non-transfixing, intraarticular implant placement into the sacroiliac joint effective January 1, 2023. These procedures are contrasted from CPT 27279 procedures, where the vignette details in numerous places the lateral, transiliac placement of implants, and the implant placement trajectory taken by the surgeon (“across the ilium, across the SI joint, and into the sacrum”).

Numerous articles have been written on this evolving topic:

• www.aapc.com/blog/51949-make-a-case-for-unlisted-codes
• www.aapc.com/blog/69274-coding-for-mis-procedures-with-direct-visualization

Coding Expert: Machelle Morningstar, CPC, COC, CEMC, COSC

Machelle Morningstar is the president of Morningstar Coding and Reimbursement Consultants, focusing on the medical device field. Machelle has been coding for 39 years and specializes in orthopedics. She is an active member of the American Academy of Professional Coders (AAPC), and is the founder and past president of the Washington, D.C., local AAPC chapter.

Access Machelle’s AAPC Healthcare Business Monthly articles on sacroiliac joint procedural coding:

aapc.com/blog/author/mmorningstar

Increase to Work RVUs based on lateral SI joint procedures

The interpretation that CPT 27279 is a lateral, transiliac “transfixing device” procedure is now a consensus among the coding community. This interpretation is also shared by providers who routinely perform the procedure. In the CY 2020 Medicare Physician Fee Schedule Final Rule, more than 80 orthopedic surgeons and neurosurgeons with expertise in SI joint procedures commented publicly to the Medicare program about the need to increase Work RVUs for CPT 27279, based on the lateral, transiliac “transfixing device” procedure they perform for their patients. After hearing the comments directly from surgeons performing lateral, transiliac SI joint fusion procedures, CMS increased the Work RVUs associated with the code, to reflect the work intensity and effort required.

In December 2020, the International Society for the Advancement of Spine Surgery (ISASS) issued clinical guidelines and coding recommendations for SI joint procedures. In its guidance, ISASS distinguishes the lateral, transiliac “transfixing device” SI joint procedure from the newer interpositional dorsal procedure, and specifically recommends that physicians do not use CPT 27279 to report the newer interpositional dorsal procedure because they consider it to be substantially different from anything described in CPT.

What should ASCs and coders do now?

ASC operators, as well as their coding and billing teams, should ask for more documentation from physicians reporting SI joint procedures to determine the appropriate CPT to report; and providers should plan to develop the most specific operative notes possible for their coders. If details are lacking, coders should query the physician to elicit details about the case, including surgical approach, incision size, and device(s) or implant(s) used, to make the best determinations on coding and claims filing.

Coders are taught to use unlisted coding, such as those for spine (22899) or hip/pelvis (27299) procedures, when there is no code available in CPT to describe a procedure or service; a CPT code may not be selected merely because it approximates a service or procedure. Machelle recommends that coders consult resources such as the AMA CPT Assistant journal and the CPT Knowledge Base, ask for more operative documentation, and make a plan to report unlisted CPT code(s) to third-party payors as applicable, to describe any new service not described in CPT.

*CPT® 27279, Arthrodesis, sacroiliac joint, percutaneous or minimally invasive (indirect visualization), with image guidance, includes obtaining bone graft when performed, and placement of transfixing device. CPT® is a registered trademark of the American Medical Association.