Orthopaedic practices commonly question how to correctly code and bill for surgical assistant services for both physicians and nonphysician providers (NPPs). Although commercial rules for reporting surgical assistant services can and do vary markedly, the Medicare rules apply across the country and are quite clear. In addition, Current Procedural Terminology® (CPT) clearly defines relevant modifiers and their use.

The March/April 2007 issue of AAOS Now addressed the use of modifier AS for surgical assistant services provided by NPPs. This issue will examine the use of other modifiers for surgical assistant services.

Modifier 80—Assistant Surgeon
Surgical assistant services may be identified by adding modifier 80 to the usual procedure number(s). This modifier is intended for use by physicians acting as assistant surgeons in conjunction with other physicians. Although primary surgeons do not need to affix a modifier, assistant surgeons must affix modifier 80 on bills for the surgical codes. For example, if Dr. Primary bills 27447, Dr. Assistant should bill 27447-80.

Modifier 81—Minimum Assistant Surgeon
Although not widely used, modifier 81 added to the usual procedure number(s) indicates minimum surgical assistant services. This modifier is appropriate in those instances in which the assistant surgeon assists with part of a surgical procedure, but is not present for the entire procedure. There are no written guidelines on what constitutes a “minimum” presence to report the service; the physician’s discretion determines when reporting services with modifier 81 is appropriate.

Commercial insurance companies may direct practices to use modifier 81 to designate assistant-at-surgery services performed by NPPs such as physician assistants, nurse practitioners, and clinical nurse specialists. Practices are strongly encouraged to obtain such directives in writing and retain that information on file, because the use of modifier 81 for NPP services is not in keeping with the definition per CPT. In fact, if an audit is conducted, practices that use modifier 81 to signify NPP-assisted services at the verbal directive of the payor may be required to return those payments unless they have written proof of the directive from the plan.

Modifier 82—Assistant Surgeon (when qualified resident not available)
The unavailability of a qualified resident is a prerequisite for use of modifier 82 appended to the usual procedure code number(s). Because Medicare reimburses academicinstitutions for resident services, practices in those settings will have to justify claims for assistant surgeon services.

Medicare will reimburse for assistant surgeon services—even in a setting with residents—if there is no qualified resident available. This may mean that no residents are available (a distinct possibility because of the 80-hour work restrictions) or that the residents available do not have sufficient training to properly assist with the procedure.

When submitting Medicare claims with modifier 82, the practice/department must have a signed attestation on file confirming that no qualified residents were available. This attestation would be needed during an audit of practice records, so it should be filed in the patient’s medical record or scanned into the electronic medical record.

Occasionally, commercial plans will attempt to deny assistant surgeon services, citing the availability of residents. But unlike Medicare, these commercial plans do not pay into graduate medical education funds. Thus, these attempts to circumvent payment for medically necessary assistant surgeon services are unacceptable. Although this issue is perhaps best managed during contract negotiations, the plans may have claim adjudication systems with automatic edits, based on place of service, which are difficult to adjust. If such denials occur, the practice may need to use modifier 82 and note that a signed attestation is on file to bypass system edits.

Surgical Assistant Procedure Coverage
Not all surgical services are eligible for surgical assistant payment. For each surgical CPT code, Medicare publishes the assistant payment status: payable, not payable, or possibly payable based on submitted documentation.

For example, total hip arthroplasty (27130) has a Medicare assistant payment status of “2—Assistant surgery may be paid.” In contrast, carpal tunnel release (64721) has a Medicare assistant payment status of “1—Assistant surgery may not be paid.” Although many of these status codes may seem intuitive, orthopaedic surgeons are often surprised to learn that several knee arthroscopy codes—including meniscectomy (29881)—are rated as “0—Payment restrictions for assistants at surgery apply to this procedure unless supporting documentation is submitted to establish medical necessity.”

If the CPT code has a “0” status indicator, the operative note will need to clearly state why the assistant was required and the extent of the work performed by the assistant to support payment. The primary surgeon is responsible for including this enhanced documentation in the operative note. Without such information, billing personnel will find appeal efforts difficult.

Commercial payers may follow Medicare’s surgical assistant payment guidelines or may create their own. Practices should ask their top commercial payers how surgical assistant payment status is determined. In some instances, payers use the American College of Surgeons surgical assistant survey (available at www.facs.org/ahp) to determine payment.

Billing staff must have access to assistant payment status lists when they review related denials to ensure proper action and appeal efforts.

No appeal is needed if ineligible codes were billed for assistant services, but an “assistant surgery coded in error” adjustment is appropriate.

Commercial claims for assistant services that are payable per the Medicare guidelines should be appealed unless the plan has clarified their own assistant payment guidelines.

Action Steps

1. Review available modifiers for surgical assistant services and outline which modifiers are appropriate to report services performed in the practice.
2. Ensure that NPP assistant services billed to Medicare are submitted under the NPP’s name and number, with the modifier AS, and that services are eligible for assistant payment.
3. Inquire about relevant state legislation governing payment for assistant-at-surgery services by clinical personnel such as nurses or technicians.
4. Inquire what modifier is required to signal NPP (or additional clinician if allowed) assistant services for top commercial plans; also find out how the plans determine assistant payment status (Medicare or other list).
5. Review explanation of benefit statements containing surgical assistant denials to understand payment issues the practice is experiencing.

For additional information on this subject, consider the following resources:

Wiskerchen S: Billing basics for physician assistants and nurse practitioners. J Med Pract Manage 2004;19:175-178.

Bever J: Podcast: Avoiding common billing pitfalls: Non-physician providers. SoundPractice.net (Visit: http://www.soundpractice.net to download).

AAOS/KZA 2007 Reimbursement Course: Before and Beyond the Codes: How to Improve Your Business. Visit http://www.karenzupko.com for information and registration.

Jennifer Bever, MS, FACHE, is a consultant with KarenZupko & Associates, Inc.