Global Surgery Periods Explained: A Guide for Billing Teams

The global surgery package bundles three categories of services into a single payment: pre-operative services, intraoperative services, and post-operative services. The specific components included in each category are defined by CMS policy and don't change based on individual patient circumstances — if a service is in the package, it's in the package regardless of how much or how little post-operative care was actually provided.

Pre-operative services included: The pre-operative visit on the day before or day of surgery (for major procedures with a 90-day global) is included in the global payment. The surgical consultation or evaluation at which the decision for surgery was made is separately billable if it meets the criteria for modifier 57 — but routine pre-operative workup after the surgery is scheduled is generally part of the package.

Intraoperative services included: The entire operative session is included — the procedure itself, any additional services performed during the same operative session that are directly related to the primary procedure, and post-operative recovery room care provided by the surgeon. Complications arising during surgery that require additional intraoperative work by the same surgeon are generally included unless they qualify as a separate procedure under modifier 78.

Post-operative services included: All follow-up care related to the surgical procedure, provided during the global period, by the operating surgeon or their practice. This includes wound checks, suture removal, cast changes, and visits to monitor the expected progression of healing from the procedure. What is not included are services for complications that require a return to the operating room (modifier 78) or conditions that are unrelated to the surgery (modifier 24).

The key phrase throughout is "related to the procedure." Services that are directly connected to the surgical episode — managing expected post-operative pain, monitoring wound healing, managing the complications of the procedure — are in the package. Services for separate medical problems are not.

CMS assigns one of several global period designations to each procedure code. The designation appears in the Medicare Physician Fee Schedule as the "global surgery" indicator. The three standard post-operative periods are 0 days, 10 days, and 90 days, and each defines a different scope of included post-operative services.

0-day global period (indicator: 000): Used for endoscopic procedures and many minor surgical procedures. The global package includes the day of the procedure only. Any care the patient needs after that day — including care for complications or follow-up related to the procedure — is separately billable. A follow-up visit the next day for a procedure with a 0-day global is payable. For E&M services on the same day as a 0-day global procedure, modifier 25 still applies to any separately identifiable E&M service performed by the same physician.

10-day global period (indicator: 010): Used for minor surgical procedures. The package includes the day of surgery plus 10 calendar days after. Post-operative visits during those 10 days for care related to the procedure are not separately billable. The day of surgery and the 10 post-operative days together form a short global period that covers uncomplicated recoveries from minor procedures.

90-day global period (indicator: 090): Used for major surgical procedures — most inpatient surgery, many orthopedic and cardiovascular procedures. The package includes one day before surgery, the day of surgery, and 90 days after. This is the most common source of billing complexity because the 90-day window is long enough that patients frequently present for unrelated problems during the global period.

Two other designations matter: MMM (maternity codes, where the global concept applies but the period is defined by the obstetric package rather than a specific day count) and ZZZ (add-on codes, which carry no global period of their own and instead fall within the global period of the primary procedure they're performed with). XXX indicates the global period concept doesn't apply to that code at all.

For major procedures with a 90-day global period, the global package includes pre-operative visits on the day immediately before surgery. For the decision-for-surgery visit — the encounter at which the physician and patient agreed to proceed with surgery — modifier 57 allows separate billing of that E&M service. Understanding the distinction between these two types of pre-operative encounters is where billing errors occur.

The decision-for-surgery visit (modifier 57 eligible) is the appointment where the clinical evaluation leads to the conclusion that surgery is warranted. The physician examines the patient, reviews relevant findings, discusses the risks and benefits of surgical intervention, and documents the decision to proceed. This is separately billable as an E&M service with modifier 57, because its clinical content goes beyond the routine pre-operative assessment that's built into the global package.

The pre-operative visit that's included in the global package is the routine day-before-surgery encounter — a focused assessment of the patient's readiness for surgery, review of the surgical plan, and any last-minute questions or concerns. This visit is generally brief, doesn't involve a new diagnostic workup, and doesn't constitute a separately identifiable service beyond pre-surgical preparation. It's in the package because its cost is already reflected in the global payment.

The practical billing rule: bill modifier 57 on the E&M code for the encounter at which the decision was made to operate. Don't bill modifier 57 on a routine pre-operative visit for a patient who already decided on surgery at a prior encounter. If the patient presented for surgery after a prior visit decision, the day-before visit is in the global package — not separately billable.

The post-operative component of the global package covers all routine care related to the procedure during the global period. "Routine" means the care you'd expect to provide to a patient recovering normally from this type of surgery — wound management, activity instructions, monitoring for expected complications, suture or staple removal, cast or splint changes.

Services that are not included in the post-operative package, and are separately billable with appropriate modifiers:

• Treatment of complications requiring return to the OR (modifier 78): If a post-operative complication — wound dehiscence, post-operative bleeding, anastomotic leak — requires a return to the operating room, the return procedure is separately billable with modifier 78. The intraoperative services for the return procedure are payable; the pre-operative and post-operative components are not, because they're subsumed by the original global package.
• E&M services for unrelated conditions (modifier 24): If the patient presents during the global period for a problem completely unrelated to the surgery — a new acute illness, a chronic condition flare, an injury unrelated to the operative site — the E&M visit is separately billable with modifier 24. The documentation must clearly establish the unrelated nature of the visit.
• Staged or more extensive procedures (modifier 58): Procedures planned as a staged second phase of the original surgical plan, or procedures required because the initial results were insufficient, are separately billable with modifier 58. A new global period begins with the staged procedure.
• Unrelated surgical procedures (modifier 79): Surgery for a condition entirely unrelated to the original procedure is separately billable with modifier 79. A patient who had abdominal surgery and returns during the global period for a hand procedure receives full separate payment for the hand procedure under modifier 79.

Modifier 24 is the mechanism for billing an evaluation and management service that occurs during a surgical global period but is entirely unrelated to the reason for surgery. Without modifier 24, the payer assumes any E&M during the global period is post-operative follow-up — part of the package, not separately payable.

The documentation requirement for modifier 24 is clear and specific: the medical record for that visit must show that the patient presented for a problem unrelated to the surgical procedure, that the physician evaluated and managed that separate problem, and that the visit's clinical content would be recognizable as a standalone E&M encounter for that unrelated condition. A note that mentions the surgery in passing but focuses entirely on an unrelated problem with a separate diagnosis code supports modifier 24. A note that primarily discusses the surgical recovery with a brief mention of another problem does not.

Diagnosis coding on a modifier 24 visit matters. The primary diagnosis should be for the unrelated condition — not the surgical site diagnosis. If a patient recovering from a hip replacement presents with an acute upper respiratory infection, the E&M should be coded with the URI diagnosis as primary, not the hip condition. The diagnosis code itself is what tells the payer "this visit was for something other than the surgery."

A common audit pattern: payers pull claims with modifier 24 and look for notes where the diagnosis is the same as the surgical indication, or where the note content primarily discusses the surgical recovery. When the documentation doesn't match the modifier's intent — when the visit was really post-operative care but modifier 24 was applied to generate separate payment — that's an overpayment finding. The modifier has to be accurate, not just convenient.

Modifier 25 applies when an evaluation and management service is performed on the same day as a procedure with a 0-day or 10-day global period. It signals that the E&M was a significant, separately identifiable service beyond the pre-procedure evaluation — not the assessment immediately preceding the procedure itself.

The 0-day global procedure scenario is the most common context for modifier 25. A patient comes in for a scheduled injection, wound care, or minor excision. During the visit, the physician also evaluates a different complaint — a new symptom, a medication question, a follow-up on an unrelated condition. That evaluation and management work is separately payable with modifier 25 on the E&M code.

The documentation standard for modifier 25 is identical to modifier 24: the chart must show a separately identifiable clinical service. The key distinguishing feature from a documentation standpoint is a separately stated chief complaint or clinical problem for the E&M portion, distinct from the reason for the procedure. If the note documents only the procedure indication and the procedure itself, there's no support for a separate E&M regardless of what level was billed.

One frequently asked question: does modifier 25 require a separate note, or can the E&M and procedure be documented in a single note? Medicare guidance allows both portions to be in the same note, but the E&M portion and the procedure portion should be clearly distinguishable. In practice, separate documentation sections — "E&M encounter for [problem]" and "procedure note for [procedure]" — make the distinction cleaner and more defensible than interleaving the two in a single narrative.

These three modifiers address procedures that occur during an existing global period but aren't routine post-operative care. Each covers a distinct clinical scenario, and using the wrong modifier — or no modifier at all — generates either an incorrect denial or an overpayment.

Modifier 58 — Staged or Related Procedure: For a procedure that was planned at the time of the original surgery as a staged second step (a planned second-stage reconstruction, for example), or that became necessary because of the results of the original surgery, or that is a more extensive procedure required by the original results. Modifier 58 allows separate billing for the second procedure. It creates a new global period for the second procedure rather than continuing the original one. This distinction matters for billing subsequent post-operative care.

Modifier 78 — Return to Operating Room for Related Complication: When a complication from the original surgery requires a return to the OR, modifier 78 on the return procedure signals that this is a related intraoperative service. Payment is typically 70–75% of the normal fee schedule amount for that procedure, reflecting that only the intraoperative component is being paid — the pre-operative and post-operative care is covered by the original global package. The global period does not restart; the patient remains in the original global period.

Modifier 79 — Unrelated Procedure During Post-Operative Period: For surgical procedures performed during another procedure's global period that are entirely unrelated clinically. Full payment is appropriate because the two surgical episodes are independent. A new global period begins for the unrelated procedure. Proper documentation of the clinical unrelatedness is required — the two procedures should involve different anatomical systems or clearly separate clinical problems.

The common mistake is using modifier 78 when modifier 79 should be used, or vice versa. The test is whether the two procedures share a clinical connection. If the second procedure arises from a complication or expected staging of the first, modifier 78 or 58 is correct. If the two procedures are clinically independent, modifier 79 is correct and full separate payment is appropriate.

When a surgeon performs an operation but transfers post-operative care to another physician — or when a physician who didn't perform the surgery provides the pre-operative evaluation or the post-operative care — the global package can be split between providers using modifiers 54, 55, and 56. Each modifier represents a different component of the global package.

Modifier 54 — Surgical Care Only: The performing surgeon bills the procedure code with modifier 54, indicating that they performed the surgery but are not providing post-operative care. Payment is a percentage of the full global payment — approximately 70% for most major procedures, reflecting the surgical portion of the global package without post-operative follow-up.

Modifier 55 — Post-Operative Management Only: The physician providing post-operative care (typically a primary care physician or a different surgeon who assumed care) bills the same procedure code with modifier 55. Payment is a percentage of the global payment representing the post-operative management portion — approximately 30% for major procedures.

Modifier 56 — Pre-Operative Management Only: Less commonly used, modifier 56 indicates that the physician provided only the pre-operative evaluation and management, not the surgery or post-operative care. This is rare in practice but exists for situations where care is fragmented across providers in a documented way.

The split billing modifiers require coordination between providers — the total payments for all components should not exceed 100% of the global package. Payers typically track these splits and will deny overpayment if the total claimed across all providers exceeds the global rate. When a practice transfers post-operative care, documenting the transfer in the medical record and confirming that the billing reflects only the services actually provided by each provider prevents both underpayment and overpayment.

The global surgery period is one of the most consistently cited areas in MAC audits and OIG work plans. The patterns they find are predictable — and preventable with the right billing processes.

Billing post-operative visits without a modifier: The most common finding is E&M services billed during a global period without modifier 24. The payer adjudicates these as included in the global package and denies them. When auditors review the charts, they typically find that the denied visits were indeed post-operative follow-ups — not unrelated care — and the denial was correct. The issue is that someone in the billing chain billed the visit without knowing it was in the global period.

Using modifier 24 for surgical follow-up: The inverse error: applying modifier 24 to a visit that actually was post-operative care for the surgical condition, in order to generate separate payment. The documentation supports only the surgical follow-up, not a distinct unrelated problem. This is an overpayment finding in an audit.

Not tracking the global period end date: Billing teams that don't track when a 90-day global period expires will sometimes deny reimbursement for visits after the period ends by incorrectly assuming they need a modifier, or — more expensively — will fail to catch visits during the global period that shouldn't have been billed.

Incorrect modifier application on return procedures: Using no modifier on a return-to-OR procedure during an active global period, when modifier 78 or 79 should have been used. Without a modifier, the payer sees a duplicate surgical claim during the global period and denies it. The procedure may be entirely payable with the correct modifier, but without it, the billing team gets a denial and has to rework the claim.

The fix for all of these: a global period tracking field in your practice management system that's populated at the time of surgery and visible on every subsequent claim for that patient during the global window. When a billing team member can see "Patient is in 90-day global period for CPT 27447, ends [date]" on the claim screen, modifier decisions become systematic rather than ad hoc.