Assistant-at-Surgery and Co-Surgery - Understanding the Differences

To be paid the correct amount for surgery, it is important to understand the differences between assistant-at-surgery and co-surgeon. Always check the Medicare Physician Fee Schedule Fee Indicator List and Descriptions in the Resources below.

CPT range 10021 - 69990 with assistant at surgery indicator of 0 or 2 on the Fee Schedule Indicator list column A

  • 0 (Zero) - Payment restriction for assistants at surgery applies to this procedure unless supporting documentation is submitted to establish medical necessity
  • 2 - Payment restrictions for assistants at surgery do not apply to this procedure. Assistant surgeon may be paid

Assistant-at-Surgery

  • Fee Schedule payment - 16 percent of fee schedule amount
  • Append modifier AS when non-physician practitioner is assisting principal surgeon as assistant surgeon
  • Append modifier 80 (assistant surgeon), 81 (minimum assistant surgeon), or 82 (qualified resident surgeon not available) with physician assisting at surgery
  • Non-physician practitioners (physician assistant, nurse practitioner, and clinical nurse specialist) billing direct are paid 85 percent of the assistant-at-surgery amount
  • Must be reported with Type of Service 08

Co-Surgery

  • The individual skill of two surgeons (each in a different specialty) required to perform surgery on same patient during same operative session
    • Can also mean two surgeons performing parts of procedure simultaneously (such as a heart transplant)
  • May be required due to complex nature of the procedure and/or the patient’s condition, and the additional physician is not acting as an assistant-at-surgery
  • Both surgeons must document medical necessity for needing two surgeons in the patient’s medical record
  • Surgical procedures involving two surgeons performing parts of the procedure simultaneously
    • Reimbursement is 62.5 percent of the fee schedule amount
    • Indicator on the Medicare Physician fee schedule must be a 1 or 2
  • Documentation of medical necessity for two surgeons required for certain services
  • If both surgeons are required to perform specific procedures, each surgeon will bill the procedure with modifier 62
    • If both surgeons are performing separate procedures, co-surgery rules do not apply
    • Reimbursement is 62.5 percent of the fee schedule amount

Resources

Last Updated Jan 09 , 2025