CMS Co-Surgeon Guidelines: Modifier 62, Payment, and Denials

Under CMS co-surgeon guidelines, Modifier 62 is the billing modifier two surgeons of different specialties append to the same CPT code when each performs a distinct, medically necessary part of a single procedure. Each surgeon is paid 62.5% of the Medicare Physician Fee Schedule amount for that code, and the arrangement only works on procedures CMS has flagged as eligible for co-surgery.¹

When Two Surgeons Count as Co-Surgeons

Co-surgery means two surgeons, each from a different specialty, working together as primary surgeons on one procedure during the same operative session. Each performs a distinct, necessary portion of the operation. A heart transplant is the textbook case: one surgeon removes the diseased heart while the other prepares and implants the donor organ.²

An assistant surgeon is a different role and a different payment. An assistant helps the primary surgeon without independently performing a separate component of the procedure, and Medicare pays the assistant only 16% of the fee schedule amount.³ Calling a co-surgeon an assistant underpays the work. Calling an assistant a co-surgeon creates an overpayment that CMS will recoup. The role each surgeon actually played, as shown in the operative report, controls the answer.

Checking Whether the Procedure Is Eligible

Modifier 62 does not work on every CPT code. CMS assigns each code a co-surgeon Payment Policy Indicator in the Medicare Physician Fee Schedule Database, and that indicator decides whether co-surgery billing is even allowed.¹ Look up the code before the case, not after.

Indicator 2: co-surgeons are permitted without extra documentation, as long as the two surgeons are from different specialties.
Indicator 1: co-surgeons may be paid, but the claim must include documentation establishing medical necessity for two primary surgeons on that particular case.
Indicator 0: co-surgeons are not permitted. A Modifier 62 claim on this code will be denied.
Indicator 9: the co-surgery concept does not apply, which is typical for non-surgical services like evaluation and management codes.⁴

Do not assume that because a similar code was eligible last time, this one is too. Verify each code, each case.

The Different-Specialty Requirement

CMS defines co-surgery as requiring two surgeons “each in a different specialty.”¹ On indicator “2” procedures, Medicare Administrative Contractors will deny the claim outright if the two surgeons share a specialty. There is no workaround.

Indicator “1” procedures leave a narrow opening. Because those codes already demand documentation to establish medical necessity, two same-specialty surgeons could in theory justify the arrangement with strong enough clinical reasoning. In practice it rarely survives audit, and most billing departments treat different specialties as a firm requirement across the board. If your case involves two same-specialty surgeons on an indicator “1” code, confirm with your MAC before submitting.

How to Bill Modifier 62

Both co-surgeons bill the same CPT code with Modifier 62 appended, on the same date of service.⁵ Medicare processes the two claims as a pair, so they need to mirror each other on the procedure code and the date. Both surgeons also need to link the same ICD-10 diagnosis code to the shared procedure code; a mismatch there can trip up processing.

The most common way this goes wrong is one surgeon appending Modifier 62 and the other forgetting it. The surgeon without the modifier may initially be paid at 100% of the allowed amount, and CMS will eventually recoup the overpayment.⁶ CMS has flagged modifier omission as a significant source of Medicare payment errors. The fix is coordination: before submitting, the two surgical offices should confirm they are using the same CPT code, the same date, and that both are appending Modifier 62.

How Much Each Co-Surgeon Gets Paid

Each co-surgeon is paid the lesser of their actual charges or 62.5% of the Medicare Physician Fee Schedule amount for the procedure. Together, the two surgeons receive 125% of the fee schedule amount.¹ The calculation uses the facility fee schedule rate, since co-surgery almost always happens in a hospital or ambulatory surgical center.

A worked example: if the facility fee schedule amount is $1,350.62, each co-surgeon receives $844.14 (62.5%), for a combined $1,688.28.⁵ An assistant surgeon on that same procedure would receive $216.10 (16%).³

Watch the “lesser of” language. If a co-surgeon’s charge is set below 62.5% of the fee schedule amount, Medicare pays the lower figure. Charge amounts should be high enough to capture the full allowed payment.

Documentation Each Surgeon Must Produce

Each co-surgeon writes a separate operative report describing the portion of the procedure that surgeon personally performed. Identical reports or a note that a second surgeon was “present” will not satisfy CMS.⁷

Each operative report should include:

A detailed description of the distinct surgical work that surgeon performed.
The name of the other co-surgeon involved in the case.⁷
A clinical explanation of why two primary surgeons were needed rather than one primary with an assistant.
The same ICD-10 diagnosis code both surgeons will link to the shared procedure on their claims.

On indicator “1” procedures the documentation bar is higher, and the operative report needs to tie the medical necessity of two primary surgeons to the specific patient’s condition or the procedure’s technical demands.¹ Vague references to “complexity” will not hold up on review. MACs set their own local guidance on what counts as sufficient, so check your contractor.

Splitting Postoperative Care

Most surgical procedures carry a 10- or 90-day global period during which follow-up visits are bundled into the surgical payment.⁸ Co-surgeons need to decide up front who manages that follow-up. Often one surgeon’s role ends at the close of the operative session while the other handles recovery.

When care is formally transferred, the surgeon performing only the operative portion bills the procedure code with Modifier 54 (surgical care only), and the surgeon taking over follow-up bills the same code with Modifier 55 (postoperative management only).⁹ Both claims use the same procedure code and date of service. A written transfer agreement must be kept in the patient’s medical record.⁸

If no formal transfer happens and the two co-surgeons share postoperative care, the global period payment is already inside each surgeon’s 62.5% share. Any unrelated provider who happens to see the patient during the global period bills their visit with standard evaluation and management codes, no special modifier.

Situations That Look Like Co-Surgery But Aren’t

Modifier 62 only applies when both surgeons perform parts of the same procedure under a single CPT code. If two surgeons from different specialties each perform a separate procedure with its own CPT code during the same operative session, that is not co-surgery, even if both procedures share an incision.² Each surgeon simply bills their own code as the primary surgeon. If one surgeon does multiple procedures in the session, the standard multiple procedure payment reduction applies to that surgeon’s claims. CMS specifically calls this out as a common billing error.

When a procedure is so complex it needs three or more surgeons from different specialties, it becomes team surgery, billed with Modifier 66 instead of Modifier 62.¹⁰ Team surgery is priced “by report” rather than by a fixed percentage split, which means slower processing and more scrutiny. The same 0/1/2/9 indicator system in the MPFSDB governs whether team surgery is allowed for a given code.⁴

Why Co-Surgery Claims Get Denied

Denials cluster in a few predictable patterns:

Modifier 62 appended to an indicator “0” code. Denied with Claim Adjustment Reason Code 54 (multiple physicians not covered for that procedure).¹
Both co-surgeons from the same specialty on an indicator “2” code. Same Reason Code 54 denial.
One surgeon appends Modifier 62 and the other omits it. The mismatched claim is denied under Reason Code 4 for an inconsistent or missing modifier.¹
Indicator “1” procedure with documentation that fails to show why two primary surgeons were medically necessary.
Mismatched CPT codes or dates of service between the two claims, preventing the system from recognizing them as a pair.

Appeals follow standard Medicare redetermination timelines. The strongest appeals put both operative reports side by side, showing each surgeon’s distinct contribution and the clinical reason for their combined role. That same documentation, produced correctly the first time, is what keeps most co-surgery claims from being denied at all.

1
Centers for Medicare & Medicaid Services. Payment for Co-Surgeons in a Method II Critical Access Hospital (CAH)
2
Centers for Medicare & Medicaid Services. Co-Surgery Not Billed with Modifier 62
3
Centers for Medicare & Medicaid Services. Medicare Claims Processing Manual – Assistant at Surgery
4
Centers for Medicare & Medicaid Services. Status Indicators
5
Noridian Medicare. Modifier 62 – JE Part B
6
Centers for Homepage Medicare & Medicaid Services. Co-Surgery Not Billed with Modifier 62
7
Novitas Solutions. Modifier 62 Fact Sheet
8
Centers for Medicare & Medicaid Services. Global Surgery Booklet
9
Centers for Medicare & Medicaid Services. Billing and Coding – Pre/Postoperative Care Date of Service
10
Noridian Medicare. Modifier 66 – Team Surgeons – Surgical Team