Surgical · Elbow

Transhumeral amputation performed using an open, circular (guillotine) technique — cutting through the soft tissue circumferentially and dividing the bone at the same level, leaving the wound open for subsequent closure.

Verified May 8, 2026 · 6 sources ↓

Medicare: $687.06
Total RVUs: 20.57
Global, days: 90
Region: Elbow

Drawn from CMSAAPCAxogenincAAOSFindacode

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 explicitly name the open, circular (guillotine) technique — not just 'amputation of upper arm'
Document the clinical indication for open technique rather than primary closure (e.g., infection, vascular compromise, traumatic contamination)
Record the level of bone transection on the humerus (proximal, mid, distal third)
Specify laterality — right or left upper arm — to support LT/RT modifier on the claim
If staged procedure is planned, document intent for secondary closure so modifier 58 on subsequent 24925 claim is supported
Neurovascular structures addressed (nerve ligation, vessel ligation) should be itemized in the operative note

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 74 Discontinued post-anesthesia 76 Repeat, same physician 77 Repeat, another physician 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 24920 describes a guillotine-style transhumeral amputation in which the surgeon divides soft tissue in a single circular pass around the upper arm and transects the humerus at that level, intentionally leaving the wound open. This open technique is chosen when primary closure is contraindicated — typically in the setting of severe infection, vascular compromise, blast injury, or traumatic amputation requiring débridement before definitive closure. It is the planned first stage of a staged amputation sequence, not a technically inferior alternative to 24900 (primary closure).

The 90-day global period covers the guillotine procedure itself and all routine postoperative management through day 90. If the patient returns for secondary closure or scar revision, that is billed separately under 24925 with modifier 58 (staged procedure). Re-amputation at a more proximal level goes under 24930, also with modifier 58 if within the global. Any neuroma management using nerve cap or targeted muscle reinnervation techniques performed at a separate session requires separate coding — the primary amputation code alone does not capture those services.

Laterality modifiers (LT/RT) are required on every claim. If the contralateral limb is amputated at the same operative session — uncommon but seen in bilateral trauma — append modifier 50 or use LT and RT on separate line items per payer preference. Surgeon documentation must distinguish this procedure from 24900 (primary closure) and 24930 (re-amputation); the operative note needs to state the open, circular technique explicitly and document the clinical rationale for staging.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	9.88
Practice expense RVU	8.59
Malpractice RVU	2.1
Total RVU	20.57
Medicare national rate	$687.06
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	$687.06
HOPD (APC 5115) Hospital outpatient department	$13,116.76
ASC (PI G2) Ambulatory surgical center (freestanding)	$6,804.43

Common denial reasons

The recurring reasons claims for CPT 24920 get rejected.

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

Missing laterality modifier (LT or RT) — required on all upper extremity amputation claims
Code billed as 24920 when wound was primarily closed — that maps to 24900, not 24920; mismatched operative note triggers edit
Subsequent closure (24925) denied when 24920 global is active and modifier 58 was omitted, failing to identify it as a planned staged procedure
ICD-10 diagnosis code does not support open technique — e.g., elective amputation without documented wound contamination or infection raises medical necessity flags
Re-amputation billed under 24920 instead of 24930, causing a code-to-clinical-scenario mismatch on audit

Frequently asked questions

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

01What is the difference between CPT 24920 and CPT 24900?

24900 is transhumeral amputation with primary closure — the wound is closed at the time of surgery. 24920 is the open, circular (guillotine) technique where the wound is intentionally left open for subsequent closure, typically because infection or contamination makes immediate closure unsafe.

02If I perform the guillotine amputation (24920) and then return to close the wound, how do I bill the second procedure?

Bill the secondary closure under CPT 24925 with modifier 58 to indicate it is a planned staged procedure within the global period of 24920. Without modifier 58, the claim will deny as a global-period violation.

03Does CPT 24920 require a laterality modifier?

Yes. Append LT or RT on every claim. Some payers accept modifier 50 for bilateral same-session amputations, but most prefer separate line items with LT and RT. Check your MAC's preference before submitting.

04Can I separately bill for nerve management (neuroma prevention) performed at the time of 24920?

Nerve ligation incidental to the amputation is included in 24920 and not separately billable. Distinct neuroma prevention techniques — such as nerve cap application or targeted muscle reinnervation — may be separately reportable; use 64999 with modifier 22 or the appropriate nerve code and submit the operative report. Payer policies on this vary.

05What ICD-10 diagnoses support medical necessity for the open guillotine approach?

Common supporting diagnoses include traumatic amputation with open wound, necrotizing infection, gas gangrene, severe crush injury, and vascular occlusion with tissue necrosis. The diagnosis must explain why primary closure was not performed — a clean elective amputation coded to 24920 will draw scrutiny.

06Is 24920 subject to SNF consolidated billing?

Yes. CMS consolidated billing rules include 24920 in the SNF payment bundle. If the patient is a Part A SNF beneficiary at the time of surgery, the professional fee may still be billed separately to Part B, but confirm Part A versus Part B status before submitting.

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 guillotine technique, level of humeral transection, laterality, and the clinical rationale for leaving the wound open (infection, contamination, vascular status). It flags if the dictation says 'primary closure' — which maps to 24900, not 24920 — preventing a downstream coding mismatch that auditors catch on operative note review. For staged cases, the scribe notes planned secondary closure to pre-populate modifier 58 on the follow-up 24925 claim.

See how Mira captures CPT 24920 documentation