Modifier 66 (Surgical Team) is used when three or more physicians work together as a surgical team to perform a single, highly complex surgical procedure. Each physician functions as a primary member of the surgical team and contributes specialized knowledge and technical expertise that cannot reasonably be provided by one or two surgeons alone.

Modifier 66 is far less common than Modifier 62 because it is reserved for exceptionally complex procedures, such as organ transplantation, major craniofacial reconstruction, separation of conjoined twins, or other surgeries requiring multiple surgical specialties working simultaneously.

Under Medicare, Modifier 66 is only appropriate for procedures that have an eligible Team Surgery Indicator in the Medicare Physician Fee Schedule Database (MPFSDB). Each surgeon reports the same CPT® procedure code with Modifier 66, and payment is generally determined “by report” after review of the submitted documentation.

Modifier Number

Modifier Name

Surgical Team

Note: The official CPT® descriptor is maintained by the American Medical Association (AMA). Always consult the latest licensed CPT® codebook for the official wording.

Plain English Explanation

Modifier 66 tells the payer:

“This surgery required a team of three or more surgeons working together because the procedure was unusually complex and demanded multiple areas of surgical expertise.”

Unlike Modifier 62, which involves two primary surgeons, Modifier 66 involves an organized surgical team consisting of three or more surgeons.

Purpose of Modifier 66

Modifier 66 is used to:

Report highly complex team surgery.
Identify procedures requiring three or more primary surgeons.
Support reimbursement for multidisciplinary surgical care.
Differentiate surgical teams from co-surgery and assistant surgery.
Comply with CMS and payer-specific billing policies.

Understanding Surgical Team Procedures

A surgical team is required when:

Multiple surgical specialties are necessary.
The patient’s condition is extremely complex.
One or two surgeons cannot safely perform the procedure alone.
Specialized equipment and personnel are required.
Several surgeons perform different essential portions of the same procedure simultaneously.

Typical procedures include:

Multi-organ transplantation.
Separation of conjoined twins.
Complex craniofacial reconstruction.
Major oncologic resections involving several specialties.
Highly complex congenital anomaly reconstruction.

CMS notes that team surgery generally involves more than two surgeons of different specialties and often includes other highly skilled personnel and specialized equipment.

Team Surgery Indicators (Medicare)

The Medicare Physician Fee Schedule Database assigns a Team Surgery Indicator to eligible procedures.

Indicator	Meaning
0	Team surgery not permitted.
1	Team surgery may be paid; documentation required to establish medical necessity.
2	Team surgery permitted.
9	Concept does not apply.

Always verify the Team Surgery Indicator before billing Modifier 66.

When to Use Modifier 66

Modifier 66 may be appropriate when:

Three or more surgeons perform one highly complex procedure.
Each surgeon performs a distinct essential component.
The procedure is eligible for team surgery.
Medical necessity supports the use of a surgical team.
Documentation clearly identifies each surgeon’s responsibilities.

Common Examples

✔ Liver transplant involving transplant, vascular, and hepatobiliary surgeons.

✔ Separation of conjoined twins.

✔ Complex skull-base tumor surgery involving neurosurgery, ENT, and plastic surgery.

✔ Multi-specialty pelvic exenteration.

✔ Complex congenital cardiac surgery requiring several surgical specialists.

When NOT to Use Modifier 66

Do not use Modifier 66 when:

Only one surgeon performs the procedure.
Two surgeons perform the procedure (Modifier 62 may apply instead).
One physician only assists another surgeon (Modifiers 80, 81, 82, or AS may apply).
Surgeons perform separate CPT® procedures instead of sharing one procedure.
The procedure has a Team Surgery Indicator of 0.

Medicare Rules

CMS has strict rules governing Modifier 66.

Important Medicare requirements include:

More than two surgeons must participate.
Each surgeon reports the same eligible CPT® code with Modifier 66.
The procedure must have an eligible Team Surgery Indicator.
Documentation must establish why a surgical team was medically necessary.
Team surgery claims are generally reimbursed “by report” after medical review rather than by a fixed percentage.

Commercial Insurance Rules

Commercial payer policies vary.

Many insurers:

Follow CMS guidance.
Require detailed operative reports.
Require documentation explaining the need for a surgical team.
Review Modifier 66 claims manually.
Use Medicare Team Surgery Indicators as guidance.

Always verify payer-specific policies before claim submission.

Documentation Requirements

Documentation should include:

Complete operative report.
Description of the overall procedure.
Name and specialty of every participating surgeon.
Specific operative responsibilities of each surgeon.
Medical necessity explaining why a surgical team was required.
Procedure date.
Physician signatures.

The operative documentation should clearly demonstrate that each physician functioned as a primary surgical team member, not merely as an assistant.

Real Billing Examples

Example 1 – Liver Transplant

A transplant surgeon, vascular surgeon, and hepatobiliary surgeon jointly perform a complex liver transplant.

Each surgeon performs separate, essential portions of the same procedure.

Modifier 66 may be appropriate.

Example 2 – Separation of Conjoined Twins

A multidisciplinary team consisting of pediatric surgeons, plastic surgeons, orthopedic surgeons, and neurosurgeons performs the separation procedure.

Because multiple surgeons are required to complete one highly complex operation, Modifier 66 may apply.

Example 3 – Skull Base Tumor

A neurosurgeon, ENT surgeon, and reconstructive plastic surgeon perform one skull-base tumor resection requiring simultaneous specialized expertise.

Modifier 66 may be appropriate if payer requirements are met.

Example 4 – Incorrect Use

Two orthopedic surgeons jointly perform a spinal fusion.

Modifier 66 should not be reported.

Modifier 62 may be appropriate if the procedure qualifies for co-surgery.

CMS-1500 Claim Example

Field	Example
CPT Code	Eligible surgical CPT® code
Modifier	66
Diagnosis Pointer	Appropriate ICD-10-CM diagnosis
Units	1
Charges	Provider’s billed amount

Each surgeon submits an individual claim using the same CPT® code with Modifier 66.

Common Denial Reasons

Procedure not eligible for team surgery.
Fewer than three surgeons participated.
Documentation does not support medical necessity.
Missing operative reports.
Incorrect use instead of Modifier 62.
Team Surgery Indicator does not permit Modifier 66.

How to Correct the Denial

Review the Explanation of Benefits (EOB) or Electronic Remittance Advice (ERA).
Verify the Team Surgery Indicator.
Confirm that three or more surgeons participated.
Submit complete operative reports.
Include documentation supporting medical necessity.
Appeal with complete clinical records when appropriate.

Coding Tips

Always verify the Team Surgery Indicator before billing.
Modifier 66 applies only to three or more surgeons.
Do not confuse Modifier 66 with Modifier 62.
Ensure every participating surgeon reports Modifier 66.
Maintain detailed documentation because most claims are reviewed individually.

Modifier 66 vs Modifier 62 vs Modifier 80

Modifier	Purpose
62	Two primary surgeons perform distinct portions of the same procedure.
66	Three or more surgeons function as a surgical team.
80	Assistant surgeon assists the primary surgeon.

Modifier 66 vs Surgical Team Members

Role	Appropriate Modifier
Two primary surgeons	62
Three or more primary surgeons	66
Assistant surgeon	80
Minimum assistant	81
Assistant when qualified resident unavailable	82
PA/NP/CNS assistant	AS

Frequently Asked Questions (FAQs)

Q1. What is Modifier 66 used for?

Answer: Modifier 66 identifies a highly complex surgical procedure performed by a team of three or more surgeons working together as primary surgeons.

Q2. What is the difference between Modifier 62 and Modifier 66?

Answer: Modifier 62 is used when two primary surgeons perform one procedure. Modifier 66 is used when three or more surgeons are required because of the procedure’s complexity.

Q3. How does Medicare reimburse Modifier 66?

Answer: Unlike Modifier 62, which has a defined payment methodology, Modifier 66 is generally reimbursed by report after review of documentation supporting medical necessity.

Q4. Does every surgeon report Modifier 66?

Answer: Yes. Each participating surgeon reports the same eligible CPT® code with Modifier 66, along with supporting documentation.

AR Caller Tips

When following up on a denied Modifier 66 claim:

Verify the Team Surgery Indicator in the MPFSDB.
Confirm that at least three surgeons participated.
Ensure each surgeon billed the same CPT® code with Modifier 66.
Submit operative reports describing each surgeon’s responsibilities.
Record the payer representative’s name, call reference number, and follow-up instructions.

Interview Questions

Question 1

What is Modifier 66?

Answer: Modifier 66 identifies a surgical procedure performed by a team of three or more primary surgeons because of exceptional complexity.

Question 2

What is the biggest difference between Modifier 62 and Modifier 66?

Answer: Modifier 62 involves two primary surgeons, whereas Modifier 66 requires three or more surgeons functioning as a surgical team.

Question 3

What should a biller verify before submitting Modifier 66?

Answer: Verify that the CPT® code has an eligible Team Surgery Indicator, confirm that three or more surgeons participated, ensure each surgeon billed Modifier 66, and confirm documentation supports medical necessity.

Practice Scenario

Scenario

A patient undergoes a highly complex liver transplant. A transplant surgeon performs the graft implantation, a vascular surgeon completes complex vascular reconstruction, and a hepatobiliary surgeon performs extensive biliary reconstruction. All three surgeons work together throughout the operation, and each documents a distinct, medically necessary portion of the same procedure.

Question

Should Modifier 66 be reported?

Answer

Yes. Because three primary surgeons participated in one highly complex eligible procedure and documentation supports the need for a surgical team, Modifier 66 may be appropriate, subject to the applicable Team Surgery Indicator and payer policy.

Related Modifiers

Modifier 62 – Two Surgeons
Modifier 80 – Assistant Surgeon
Modifier 81 – Minimum Assistant Surgeon
Modifier 82 – Assistant Surgeon (Qualified Resident Unavailable)
Modifier AS – Physician Assistant, Nurse Practitioner, or Clinical Nurse Specialist Assistant at Surgery

Common Billing Mistakes

Reporting Modifier 66 when only two surgeons participated.
Using Modifier 66 instead of Modifier 62.
Failing to verify the Team Surgery Indicator.
Not documenting why a surgical team was medically necessary.
Confusing assistant surgeons with surgical team members.

Key Takeaways

Modifier 66 identifies team surgery involving three or more primary surgeons.
It is reserved for highly complex procedures requiring multiple surgical specialties.
Verify the Medicare Team Surgery Indicator before billing.
Each surgeon should report the same eligible CPT® code with Modifier 66.
Complete operative documentation is essential because reimbursement is generally determined by report.

References

CMS Medicare Claims Processing Manual, Chapter 12 – Team Surgery.
CMS Medicare Learning Network – Global Surgery Booklet.
Noridian Medicare – Modifier 66 Guidance.
AMA CPT® Professional Edition (licensed codebook).

Conclusion

Modifier 66 is a specialized procedural modifier reserved for highly complex surgeries requiring the coordinated expertise of three or more primary surgeons. Correct use requires confirming procedure eligibility, reviewing the Medicare Team Surgery Indicator, ensuring every participating surgeon reports Modifier 66 appropriately, and maintaining detailed operative documentation. Accurate reporting helps support compliant billing, reduce denials, and ensure appropriate reimbursement for multidisciplinary surgical care.

Educational Disclaimer

This article was prepared with the assistance of artificial intelligence (AI) for educational and informational purposes. It is based on publicly available CMS guidance, Medicare billing resources, and general medical billing principles. It is not an official publication of the American Medical Association (AMA), CMS, or any insurance payer. CPT® is a registered trademark of the American Medical Association. Always consult the latest AMA CPT® codebook, CMS manuals, Medicare Administrative Contractor (MAC) guidance, the Medicare Physician Fee Schedule Database, National Correct Coding Initiative (NCCI) policies, and payer-specific billing policies before coding, billing, or submitting claims.