Modifier 58: Staged Procedure During a Global Period
Modifier 58 reports a planned, staged or more extensive procedure during a global period. When it applies, how Medicare pays it, and 58 vs 78 vs 79 explained.
Modifier 58 is a billing modifier for a procedure the same surgeon performs during an earlier surgery's global period when the second procedure was planned, is more extensive, or is treatment that follows a diagnostic procedure. It gets the second procedure paid in full instead of denied as part of the first surgery's package, and it starts a new global period.
Key takeaways
- Medicare recognizes three reasons for 58: the procedure was planned at the time of the first one, it is more extensive than the first, or it is therapy after a diagnostic surgical procedure.
- 58 doesn't reduce payment. The procedure is paid at its normal fee schedule amount and a new postoperative period begins.
- A complication that sends the patient back to the operating room is 78, not 58.
- A procedure with nothing to do with the first surgery is 79.
- Codes with an XXX global indicator never need 58.
Modifier 58 · payment effect
With and without the modifier
27447 without 58 · national facility
$1,159.35
Total knee replacement
27447-58 · No change to the rate
$1,159.35
Staged or related procedure during a global period: paid at its full rate and starts a new global period.
When to use modifier 58
The Claims Processing Manual (Pub. 100-04, ch. 12, §40.2.A.6) lets surgeons report a procedure in the postoperative period of an earlier one with 58 when it was:
- Planned prospectively or at the time of the original procedure. Staged reconstructions, a series of debridements and grafts, or a second-stage hardware procedure decided on at the first operation.
- More extensive than the original procedure. A less invasive approach fails and the surgeon moves to a bigger operation. CMS lists this among services not included in the global package (§40.1.B).
- Therapy following a diagnostic surgical procedure. A biopsy shows cancer and the surgeon goes on to the definitive resection, such as a breast biopsy followed by a mastectomy (19303).
The surgeon must be the same physician, or a partner in the same group and specialty, who billed the first procedure. The first surgery's global days decide whether you need the modifier at all; the global period calculator shows the window.
Example. A surgeon performs a knee arthroscopy with meniscectomy (29881) on March 2, 2026. Symptoms continue and in May the same surgeon performs a total knee replacement (27447) on the same knee. The replacement is more extensive than the original procedure: bill 27447-58.
Global surgery period · 29881
Knee meniscectomy
90-day global period ends
May 31, 2026
Covers Mar 1, 2026 through May 31, 2026 (92 days, including the day before surgery).
Visit on Apr 1, 2026
Day 30 of the 90-day post-op period: related follow-up care is included in the surgical payment.
Pre-op dayGlobal period
When not to use modifier 58
- The procedure is unrelated to the first surgery. Use modifier 79.
- It's a visit. Unrelated postoperative visits take 24; the visit that decides on a major surgery takes 57.
- The code has an XXX global indicator. Medicare pays these without a global-surgery modifier (ch. 12, §40.4.A).
- It's a same-session bundling problem. Two procedures on the same day that NCCI bundles need 59 or an X modifier, not 58.
How modifier 58 affects payment
Modifier 58 carries no percentage. Medicare allows separate payment for procedures billed with 58 (ch. 12, §40.4.A), at the full fee schedule amount, with the usual multiple-procedure ranking if other procedures are done in the same session (modifier 51). Two consequences follow:
- A new global period begins when the next procedure in the series is billed (§40.2.A.6). Follow-up after the 58 procedure is bundled into its own package.
- Unlike 78, there's no cut to the intraoperative portion, because the staged procedure is expected work, not treatment of a complication.
Decide
Is the new service inside the global period of a surgery the same surgeon (or same-specialty group partner) already billed?
Modifier 58 vs 78 and 79
The question that separates them: was this next procedure part of the plan or a natural escalation (58), a fix for something that went wrong (78), or a different problem entirely (79)?
FAQ
What is modifier 58 used for?
To report a procedure performed during another procedure's postoperative period by the same surgeon when it was planned, more extensive than the first, or therapy after a diagnostic procedure. It lets Medicare pay the second procedure in full instead of bundling it into the first.
What modifier is used for unrelated procedures in the global period?
Modifier 79. Modifier 58 is for related procedures that were staged or expected; 79 is for procedures with no connection to the earlier surgery.
Does modifier 58 start a new global period?
Yes. CMS says a new postoperative period begins when the next procedure in the series is billed (Pub. 100-04, ch. 12, §40.2.A.6).
Does modifier 58 reduce payment?
No. Medicare pays a procedure billed with 58 at its normal fee schedule amount. Only modifier 78 limits payment to the intraoperative portion, because it covers unplanned returns to the operating room.
What's the difference between modifier 57 and 58?
Modifier 57 goes on an E/M visit that led to the decision to perform a major surgery. Modifier 58 goes on a procedure that is a planned or more extensive follow-on to an earlier surgery.
Keep reading
- Modifier 78 and modifier 79, the other procedure modifiers in the global period.
- Modifier 57 for the decision-for-surgery visit.
- Global period calculator to find the postoperative window for any surgery date.
- Codes on this page: 29881 27447 19303
Sources: CMS Medicare Claims Processing Manual, Pub. 100-04, ch. 12, §§40.1, 40.2.A.6 and 40.4; CMS MLN907166, Global Surgery (December 2025). Verified October 6, 2026.
