Summary & Overview
CPT 20956: Vascularized Iliac Crest Bone Graft with Microvascular Anastomosis
CPT code 20956 denotes a surgical microvascular procedure in which bone graft material is harvested from the hip with its vascular supply and reconnected at the recipient site using an operative microscope. This technique — often described as a vascularized iliac crest bone graft — is used to promote faster and more reliable healing where bone is missing or damaged from trauma, infection, tumor resection, or other pathology. Nationally, the code is relevant for complex reconstructive orthopedics, plastic surgery, and maxillofacial procedures that require living bone transfer and microsurgical expertise.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical context, expected site-of-service settings, and the service type tied to this code. The publication summarizes common billing considerations, typical utilization patterns, and where CPT code 20956 fits within reconstructive and orthopedic surgical coding frameworks. It also highlights benchmarks and policy updates where available and notes where input data was not provided. The goal is to give clinicians, coding professionals, and policy analysts a clear, national-level reference for the clinical intent and billing context of CPT code 20956.
Billing Code Overview
CPT code 20956 describes a vascularized bone graft harvested from the hip (iliac crest) with microvascular anastomosis at the recipient site. The procedure involves removing bone graft material together with its attached vascular supply and using an operative microscope to reconnect blood vessels at the defect site to promote healing of missing or damaged bone due to injury or disease.
Service type: Surgical — microvascular reconstructive bone grafting
Typical site of service: Hospital operating room or ambulatory surgery center
Clinical & Coding Specifications
Clinical Context
A 48-year-old male patient presents after a high-energy pelvic fracture with segmental bone loss of the proximal femur and persistent nonunion despite prior fixation. Imaging demonstrates a 4-cm osseous defect with compromised local blood supply. The orthopedic microsurgical team plans a vascularized iliac crest bone graft with microvascular anastomosis to restore structural continuity and provide a living bone graft to promote faster revascularization and healing.
Preoperative workflow includes history and physical, informed consent that documents the need for vascularized autograft, surgical planning with CT or MRI to assess defect size and donor-site anatomy, and coordination with anesthesia for general anesthesia and potential invasive monitoring. Intraoperative workflow includes harvest of the vascularized iliac crest bone graft, preparation of the recipient site, microsurgical anastomosis of artery and vein under an operative microscope, and fixation of the graft to native bone. Postoperative workflow includes flap monitoring for perfusion, pain control, DVT prophylaxis, radiographic surveillance of graft incorporation, and outpatient follow-up with progressive weight-bearing as tolerated based on radiographic healing.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
62 | Two surgeons | When two surgeons of different specialties work together and each performs distinct portions of the procedure (e.g., orthopedic surgeon and microvascular surgeon). |
66 | Surgical team | When a surgical team approach is reported for exceptionally complex cases requiring multiple surgeons functioning as a team. |
50 | Bilateral procedure | When the same procedure is performed on both left and right sides during the same operative session. |
52 | Reduced services | When the procedure is partially reduced or not completed as planned (e.g., graft harvest attempted but limited by anatomy). |
53 | Discontinued procedure | When the procedure is started but terminated due to unforeseen circumstances prior to completion. |
62 | Two surgeons | Duplicate entry removed in final use; see above. |
76 | Data not available in the input. | Data not available in the input. |
78 | Return to the operating room for a related procedure during the global period | When unplanned return to OR occurs for takeback of the vascular anastomosis. |
79 | Data not available in the input. | Data not available in the input. |
58 | Data not available in the input. | Data not available in the input. |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
| Data not available in the input. | Data not available in the input. | Data not available in the input. |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
| Data not available in the input. | Data not available in the input. | Data not available in the input. |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
20956 | Vascularized bone graft; includes harvest and microvascular anastomosis | Primary procedure: harvest and microvascular transfer of iliac crest bone graft to recipient site. |
15738 | Muscle, myocutaneous, or fasciocutaneous free flap with microvascular anastomosis | Performed when additional soft-tissue coverage is required over the bone graft site. |
27299 | Unlisted procedure, pelvis or hip joint | Used for ancillary or nonstandard pelvic procedures related to complex reconstruction when no specific code exists. |
20955 | Bone graft, any donor site, morcelized or structural, without microvascular anastomosis | Alternative when a nonvascularized iliac crest graft is used instead of a vascularized graft. |
69990 | Microsurgical techniques, requiring use of an operating microscope (list separately in addition to primary procedure) | Billed adjunctively when microsurgical microscope services are separately reportable. |