Open circular (guillotine) amputation of the forearm, transecting both the radius and ulna at any level along their shafts, leaving the wound open for staged management.

Verified May 8, 2026 · 6 sources ↓

Medicare: $660.00
Total RVUs: 19.76
Global, days: 90
Region: Wrist

Drawn from CMSAAPCFindacodeNIHAxogeninc

Documentation requirements

What must appear in the operative or office note to support the claim.

Source · Editorial brief grounded in 6 cited references ↓

Operative note must state 'open, circular (guillotine)' technique explicitly — 'amputation of forearm' alone doesn't distinguish 25905 from 25900.
Document the level of transection on the radius and ulna (proximal, mid-shaft, distal third) to support medical necessity and future revision planning.
Record the indication driving the guillotine approach: acute infection with systemic sepsis, traumatic devascularization, severe wound contamination, or other cause requiring staged closure.
If modifier 22 is appended, the operative note must quantify the additional work — e.g., extensive debridement of necrotic tissue, abnormal anatomy, prolonged operative time with reason.
Informed consent documentation should reflect the staged nature of the procedure and anticipated second-stage closure or revision.
Anesthesia and pathology consult notes (if bone or tissue sent) should align with the operative account for audit consistency.

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity 50 Bilateral procedure 51 Multiple procedures 52 Reduced services 58 Staged or related 78 Unplanned return — related 79 Unrelated during global 80 Assistant surgeon AS PA/NP/CNS assistant LT Left side RT Right side

What this code covers

Source · Editorial summary grounded in 6 cited references ↓

CPT 25905 describes a guillotine-technique forearm amputation in which the surgeon transects the radius and ulna with a circumferential incision, leaving the wound open rather than closing it primarily. This open approach is the defining distinction from CPT 25900 (primary closure). Guillotine amputation is typically the first stage in a two-step sequence: the open wound controls life- or limb-threatening infection, devascularization, or severe contamination, with formal revision, stump shaping, or skin closure billed separately under 25907 (secondary closure/scar revision) or 25909 (re-amputation) at a later operative session.

The 90-day global period means all routine post-op visits, dressing changes, and wound checks through day 90 are bundled. A return to the OR for the planned secondary closure during that window is reported with modifier 58 (staged or related procedure). An unplanned return for a complication related to the original amputation uses modifier 78. An unrelated procedure in the same global window requires modifier 79.

Assistant surgeon services are eligible — report with modifier 80 for an MD assistant or AS for a PA/NP/CNS assistant at surgery. Bilateral forearm amputation in the same session is exceptionally rare but would use modifier 50 for physician billing (LT/RT on separate lines at the ASC). Modifier 22 applies when operative complexity materially exceeds the typical case — document specific factors driving the increased work in the operative note.

RVU & reimbursement

Component RVUs and Medicare national rate. Actual payment varies by GPCI locality.

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	9.35
Practice expense RVU	8.42
Malpractice RVU	1.99
Total RVU	19.76
Medicare national rate	$660.00
Global period	90 days

Payment by site of service

Medicare pays different rates by setting. HOPD typically pays substantially more than ASC for the same procedure.

Source · CMS OPPS Addendum B·ASC HCPCS payment rates·2026

Setting	Medicare rate (national)
Office (PFS non-facility) Procedure performed in physician's office	$660.00
HOPD (APC 5114) Hospital outpatient department	$7,413.38
ASC (PI G2) Ambulatory surgical center (freestanding)	$3,695.53

Common denial reasons

The recurring reasons claims for CPT 25905 get rejected.

Source · Editorial brief grounded in CMS NCCI edits, AAOS coding appeals, and cited references ↓

Billing 25905 when the operative note describes primary skin closure — payers recode to 25900, reducing payment.
Missing or vague indication: notes that say 'infected wound' without specificity (organism, failed conservative treatment, severity) trigger medical necessity denials.
Modifier 58 omitted on same-global secondary closure (25907) — payer denies as duplicate or global-included service.
Modifier 78 and 79 confused on return-to-OR claims — inverting these modifiers causes denial or incorrect global period application.
Unbundling wound debridement codes performed as part of the guillotine technique without documentation that debridement was a separately identifiable, distinct service.

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 6 cited references ↓

01What is the difference between CPT 25905 and CPT 25900?

25900 is forearm amputation with primary closure — the wound is closed at the time of surgery. 25905 is the open guillotine variant where the wound is intentionally left open for staged management. The distinction hinges entirely on the closure technique documented in the operative note.

02When is CPT 25907 reported after a 25905 case?

25907 covers secondary closure or scar revision of the forearm stump. When performed during the 90-day global period of the original 25905, append modifier 58 to indicate it was a planned, staged procedure. Without modifier 58, the payer treats it as bundled and denies it.

03Can I bill for wound debridement separately at the time of the guillotine amputation?

Generally no. Debridement performed as part of the guillotine amputation technique is bundled into 25905. To bill debridement separately, the operative note must document it as a distinct, separately identifiable service beyond what the amputation itself required.

04Does the 90-day global apply if the patient is seen in the ED for a wound complication?

Routine post-op wound issues within the global are bundled. If the complication requires a return to the OR for an unplanned procedure related to the amputation, report that service with modifier 78. Truly unrelated procedures use modifier 79.

05Is modifier 50 realistic for CPT 25905?

Bilateral simultaneous forearm amputation is exceedingly rare but not excluded from billing rules. If it occurs, physician billing uses modifier 50 on a single line. At the ASC, report two lines — one with LT, one with RT.

06What ICD-10 diagnoses most commonly support 25905?

Gas gangrene (M00.x / A48.0), severe necrotizing fasciitis, traumatic devascularization with non-viable limb, and advanced osteomyelitis with sepsis are the primary drivers. The diagnosis code must match the documented clinical urgency for the open technique.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

Mira AI Scribe

Mira's AI scribe captures the technique descriptor ('open, circular guillotine'), the anatomical level of radius and ulna transection, and the clinical indication driving the staged open approach — infection severity, vascular status, wound contamination. That specificity prevents the most common recode from 25905 to 25900, which occurs when the operative note fails to document the open wound intent. The scribe also flags when a secondary closure or re-amputation is anticipated, prompting the billing team to plan modifier 58 for the follow-on case.

See how Mira captures CPT 25905 documentation