This month’s coding column addresses commonly asked questions related to coding or reimbursement issues.

Pediatric spine
Q: A new pediatric spine surgeon has joined the practice. He is planning a surgical procedure in which he will be placing instrumentation, but will not be doing any additional procedures at that session. How is this case coded when the surgery is performed, because the instrumentation codes are add-on codes?

A: The placement of instrumentation prior to a major spine procedure, common in pediatric structural deformity procedures, is reported using an unlisted spine code, 22899. Compare the fee for the unlisted procedure to the same instrumentation code that would have been submitted in the presence of an arthrodesis procedure.

Hardware removal at TKA
Q: The surgeon performed a total knee arthroplasty (TKA) on a patient who had previous knee surgery; the hardware was still in place. The original surgery was not performed by a member of our group and there was no transfer of care between the surgeons. The surgeon had to remove the hardware to complete the TKA. How should the hardware removal be coded? Would using a modifier (in case the patient is still in the global period for the other surgeon) be appropriate?

A: First, the hardware removal (20680—removal of deep implant) is not separately reportable at the site of more extensive surgery. Second, because the primary procedure was performed by a surgeon who is not part of the group, it would be inappropriate to use a modifier, because the practice is not in a global period for that patient.

Spine bone grafts
Q: How do I differentiate between CPT code 20937 and CPT code 20938 for a spinal bone graft using bone harvested from the iliac crest? The surgeon dictated that he removed a bone plate and harvested cancellous bone from the iliac crest. He then mixed the cancellous bone with an allograft and used it, for example, for a posterior fusion. I have been using CPT code 20938 because of the removal of the bone plate, but now I am not sure.

A: CPT code 20937 is defined as “Autograft for spine surgery only (includes harvesting the graft); morselized (through separate skin or fascial incision) (List separately in addition to code for primary procedure).”

CPT code 20938 is defined as “Autograft for spine surgery only (includes harvesting the graft); structural, bicortical or tricortical (through separate skin or fascial incision) (List separately in addition to code for primary procedure).”

Based on these definitions and the information provided, the correct code is 20937. CPT code 20937 specifies “morselized,” which allows the cancellous bone to be mixed with the allograft. CPT code 20398, on the other hand, defines a structural autograft that may more commonly be placed within an interspace to maintain height between the vertebrae. Although the cancellous bone provides “structural” support, the more accurate code in this example is 20937.

Abrasion arthroplasty
Q: An increased number of abrasion arthroplasty procedures reported with meniscectomy codes are being denied. What documentation is required to support this code?

A: An abrasion arthroplasty (CPT code 29879) is more extensive than a chondroplasty, and the documentation should support that. The surgeon is performing a more extensive procedure and débrides to “subchondral bleeding bone.” This language is important to differentiate between an abrasion arthroplasty and a chondroplasty. Regardless of the number of compartments involved, chondroplasty is now inclusive to a meniscectomy.

An abrasion arthroplasty code may also be reported when the surgeon performs a microfracture (making tiny fractures in the bone) and documents the subchondral bleeding bone that results from the tiny fractures (Fig. 1). The definition of CPT code 29879 includes a chondroplasty as noted: “Arthroscopy, knee, surgical; abrasion arthroplasty (includes chondroplasty where necessary) or multiple drilling or microfracture.” Physicians should be sure to provide a description of the clinical necessity of the abrasion arthroplasty in their operative report.

Mary LeGrand, RN, MA, CCS-P, CPC, is a senior consultant with KarenZupko & Associates, Inc., who focuses on coding and reimbursement issues in orthopaedic practices. Information in this article has been reviewed by members of the AAOS Coding, Coverage, and Reimbursement Committee.