Fibula bone graft microvasc

CPT 20955 describes a complex surgical procedure where a surgeon harvests bone from the fibula (lower leg bone) and transplants it to another location in the body, reconnecting tiny blood vessels under a microscope to keep the graft alive.

Showing rates for

National Average

Base Medicare rate

$2,371.32

This calculator gives a typical-case estimate using standard Medicare modifier rules. Actual payment depends on payer policies, documentation, code-specific CMS status indicators, and locality. Verify before billing.

RVU breakdown

Work RVU

40.26

PE RVU (NF)

26.74

MP RVU

6.31

Total RVU

73.31

Conversion factor: 32.3465 · Source: CMS MPFS RVU25A · Confidence: High

NCCI bundling edits

Loading bundling edits…

Billing tips

Document total operative time from incision to closure, number of arterial and venous anastomoses performed, and use of operating microscope with magnification level
Impact: Missing operative time documentation triggers 15-25% denial rate; complete documentation supports $2,371.32 full payment and potential modifier 22 claims worth $474-$1,186 additional
Bill the microvascular anastomosis as inclusive to 20955; do not separately report CPT 69990 (operating microscope) as it is bundled and will be denied
Impact: Separately billing 69990 results in automatic denial and creates audit flag; avoiding this prevents $350-500 denial and subsequent appeal costs
Verify pre-authorization requirements with payer before surgery; most commercial payers require prior authorization for free flap reconstruction with specific medical necessity criteria
Impact: Lack of pre-authorization causes 60-80% of initial denials for this high-cost procedure; proper authorization prevents $2,000-$8,000 in delayed or denied revenue
Document recipient site preparation and defect measurements separately from donor site harvest; include photos when possible to demonstrate complexity
Impact: Comprehensive site documentation reduces post-payment audits by 40% and strengthens modifier 22 claims; supports medical necessity determination
Bill modifier 62 co-surgery when appropriate rather than modifier 80 assistant surgeon; two qualified surgeons each receive 62.5% versus primary at 100% and assistant at 16%
Impact: Correct co-surgery billing increases total facility reimbursement by 9% ($213.42 additional) and compensates both surgeons appropriately

Live Field Datano reports yet

Real billers contribute denial patterns and appeal strategies for this code. Once 5+ reports come in, you’ll see live aggregated data here — the only place this exists, free.

Working with CPT 20955?

Get the free Revenue Protection Toolkit — the denial triggers, modifier pitfalls, and bundling conflicts that quietly cost you reimbursement. Instant download.

Help build the field knowledge

MedPayIQ gets smarter as billers contribute. If you've had this code denied, share what happened so others learn from it. Anonymous, no patient info.

Related actions

Frequently asked questions

What is the Medicare reimbursement rate for CPT 20955 in 2025?

The 2025 Medicare national average reimbursement for CPT 20955 is $2,371.32 for both facility and non-facility settings, based on 73.31 total RVUs and the conversion factor of 32.3465. This rate applies to the professional component; facility fees are billed separately by the hospital.

Can CPT 20955 be billed with an assistant surgeon modifier?

Yes, modifier 80 (assistant surgeon) is commonly used with CPT 20955 given the complexity and duration of microvascular fibula harvest. The assistant surgeon receives 16% of the allowed amount ($379.41), while the primary surgeon receives the full $2,371.32. Documentation must support medical necessity for a qualified surgeon assistant rather than a first assist.

What is the difference between CPT 20955 and 20956?

CPT 20955 describes a fibula bone graft with microvascular anastomosis, while CPT 20956 describes an iliac bone graft with microvascular anastomosis. The key distinction is the donor site anatomy; 20955 uses the fibula (leg bone) and 20956 uses the iliac crest (hip bone). Both include microvascular work but are anatomically distinct procedures selected based on recipient site requirements.

How many RVUs is CPT code 20955 worth?

CPT 20955 has 73.31 total RVUs in 2025, consisting of 40.26 work RVUs, 26.74 practice expense RVUs, and 6.31 malpractice RVUs. This makes it one of the highest-valued surgical codes, reflecting the 6-12 hour operative duration and complex microsurgical skills required.

Does CPT 20955 require prior authorization from insurance?

Most commercial payers and Medicare Advantage plans require prior authorization for CPT 20955 due to the high cost and complexity of microvascular bone grafting. Traditional Medicare does not require prior authorization but does require clear medical necessity documentation. Verify specific payer requirements before surgery to prevent denials.

Can you bill CPT 69990 for operating microscope use with CPT 20955?

No, CPT 69990 (operating microscope) should not be billed separately with CPT 20955. The use of the operating microscope for microvascular anastomosis is included in the 20955 code descriptor and bundled per NCCI edits. Billing both codes will result in denial of 69990 and potential audit flags.

What diagnosis codes support medical necessity for CPT 20955?

Common supporting diagnoses include C41.x (malignant bone neoplasm requiring resection), M87.x (osteonecrosis requiring vascularized reconstruction), S72.x or S82.x (traumatic bone defects), M84.x (pathological fracture/nonunion), and Q75.x (congenital mandibular defects). Documentation must specify defect size >6cm and explain why non-vascularized grafts are inadequate for the specific clinical scenario.