Assistant-at-Surgery

Assistant Surgeon 

When it comes to surgery, the assistant surgeon plays a hands-on role in helping the primary surgeon carry out the procedure. This isn’t just someone standing by to offer occasional support—they’re actively involved in the operation. To reflect this, the surgical report should clearly outline what the assistant did during the procedure, showing that their contribution went beyond basic support.

Modifier -80 (Assistant at Surgery performed by a Physician)

• For use in procedures outside of an academic setting

Documentation:

• The procedures or services performed and support the use of modifiers
• The name of the assistant
• Evidence the assistant surgeon actively participated in the procedure
• Clearly document the assistant’s role during the operative session.
  • Primary surgeon must demonstrate medical necessity for assistant surgeon
  • Assistant’s role provides more than ancillary services
• Primary surgeon’s signature.
  • Assistant is not required to sign the operative report.
  • Best practice, assistant write a brief note tying to the operative report in the event that the primary surgeon omits their name and role in the surgery.

Clinical Example:

During a total knee replacement, the primary orthopedic surgeon performs the procedure, but a second physician assists throughout—helping with exposure, retraction, and closure.

• Use Modifier -80 to bill for the assistant surgeon’s role.
• This is a full assist, not just a brief or minimal one

Modifier -82 (A qualified Resident was not Available)

• Unavailability of a qualified Resident in a teaching setting
• This modifier is not intended for use by non-physician providers (see -AS modifier).

Documentation:

When billing for an assistant surgeon in a teaching hospital, it’s crucial to document why a resident or fellow wasn’t available—or wasn’t qualified—to assist in the procedure. This detail should be clearly stated in the medical record, especially if the operative report mentions a resident or fellow alongside the assistant surgeon, or advanced practice provider.

Why is this important? Because if a resident or fellow was present, the documentation must explain why they couldn’t fulfill the assistant role. Without that clarification, it may appear that the assistant surgeon wasn’t necessary.

Here are a couple of valid reasons that should be documented:

• Resident or fellow was present but not scrubbed in – They may have been observing or assisting in a non-sterile capacity.
• Resident or fellow wasn’t qualified for the complexity of the procedure – For example, in highly specialized or technically demanding surgeries, a more experienced assistant may be required.

Clear documentation helps ensure compliance and supports the medical necessity of billing for an assistant surgeon in a teaching environment.

Clinical Example:

In a teaching hospital, a general surgeon performs a laparoscopic cholecystectomy. Normally, a surgical resident would assist, but none are available. A second attending surgeon steps in to assist.

Assistant-at-Surgery 

Though an assistant at surgery may also be a physician, most often it is referred to when the assistant is other than a physician (NP, PA, or CNS). When an advanced practice provider assists at surgery, modifier -AS should be appended to the service, not -80, -81, or -82.

Modifier -AS (Assistant at surgery services provided by a physician’s assistant (PA), nurse practitioner (NP), or clinical nurse specialist (CNS).

Documentation:

1. Statement of Resident Unavailability (if performing in an academic facility)
   • The medical record must clearly state that no qualified resident was available to assist during the procedure.
2. Clinical Justification for NPP Assistance
   • Include a brief explanation of why the NPP was needed, such as complexity of the case or urgency.
3. Operative Note Details
   • The operative report should describe:
     • The specific tasks performed by the NPP.
     • The extent of their involvement in the procedure.
     • Confirmation that the NPP was scrubbed in and actively assisting.

Clinical Scenario:

A physician assistant (PA) assists a cardiovascular surgeon during a coronary artery bypass graft (CABG). The PA helps with harvesting the saphenous vein and assists with suturing.

Academic Setting:

A qualified resident was not available due to a conflict with rounds.  Therefore, Sue Smith, PA assisted the cardiovascular surgeon during a coronary artery bypass graft (CABG). She helped with the harvesting of the saphenous vein and suturing.

Minimal Assistant Surgeon 

-81 is used to indicate minimal surgical assistance provided by a physician during a procedure. This modifier applies when the assistant surgeon is involved only for a specific portion of the surgery—typically due to an unexpected complication—and not throughout the entire operation.

• The assistant helps with a specific task, like controlling bleeding or managing tissues.
• The help is brief and limited, not continuous throughout the procedure.
• The procedure must be eligible for assistant services under Medicare’s guidelines (Assistant Surgeon Indicator 2 or 0 with documentation).

Modifier – 81

Documentation:

• Why the assistant was needed (e.g., surgical complication).
• What specific tasks they performed.
• How long they were involved.

Clinical Scenario:

If a surgeon performing a laparoscopic gallbladder removal accidentally punctures the gallbladder and calls in another physician to help drain bile and prevent infection, that second physician’s role would be billed using Modifier 81.

Co-Surgeons

The individual skills of two surgeons are required to perform surgery on the same patient during the same operative session. This may be required because of the complex nature of the procedure(s) and/or the patient’s condition and the additional physician is not acting as an assistant at surgery.

If the two surgeons (each a different specialty) are required to perform a specific procedure, each surgeon bills for the procedure with a modifier 62.

There are some cases where two surgeons from the same specialty may perform as co-surgeons, such as a heart transplant or bilateral knee replacements. Be prepared to submit operative reports for each co-surgeon.

Modifier – 62

Documentation:

When billing for co-surgery using Modifier 62, proper documentation is essential—especially when the Medicare Physician Fee Schedule Database (MPFSDB) indicator is “1.” This means co-surgery may be allowed, but only if medical necessity is clearly supported.

To ensure compliance, the documentation should paint a clear clinical picture and include the following:

• Details of the procedure or service performed, with justification for using Modifier 62
• Name of the co-surgeon involved
• Clinical necessity for having a co-surgeon
• Signature of at least one surgeon
• Description of the distinct surgical roles each co-surgeon performed
• Additionally, if the procedure involves two different specialties, include the National Provider Identifier (NPI) of the rendering physician.
•  Note: If the two-specialty requirement is met, no further documentation is needed.

However, if these requirements aren’t met, each surgeon must provide documentation that clearly supports the medical necessity of their involvement.

Finally, claims submitted with Modifier 62 should follow the Unsolicited Paperwork (PWK) process to ensure all required documentation is properly attached and reviewed.

Clinical Scenario:

An orthopedic surgeon and a general surgeon perform an anterior lumbar interbody fusion. The general surgeon handles the anterior approach, while the orthopedic surgeon performs the fusion and instrumentation.

• Both surgeons bill the same CPT code (e.g., 22558) with Modifier -62, each submitting their own operative note.

Final Thoughts
Navigating assistant surgery modifiers can feel complex, but understanding the roles, requirements, and documentation standards makes all the difference. Hopefully, this guide has helped clarify the who, what, when, and where of reporting an assistant or co-surgeon—giving you a solid foundation to move forward with confidence.

Resources:

CMS – Global Surgery

Novitas – Assistant at Surgery Fact Sheet

Novitas Modifiers:  -80, -81, -81 and -AS

Novitas Modifiers: -62 Co-Surgeon Fact Sheet

Weill Cornell Medicine – Assistant-at-Surgery Policy

MSHBC (Internal Link Only)

Assist Surgery Audit Check List