CPT code 20970 represents a vascularized iliac crest bone graft with an attached layer of cutaneous tissue used to fill bony defects and repair accompanying soft-tissue loss from trauma or disease. This complex reconstructive surgery combines structural bone replacement with soft-tissue coverage and is typically performed in hospital operating rooms or specialized surgical centers. The code is nationally relevant because it applies to high-complexity surgical reconstructions that have implications for surgical planning, payer coverage decisions, and resource use across inpatient and outpatient surgical settings. Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will learn the clinical context and intended use of CPT code 20970, typical sites of service, common payer coverage considerations, and where to look for related coding and billing guidance. The publication also highlights benchmarks and policy updates where available, and provides practical context for coding teams, billing professionals, and surgical departments handling complex reconstructive procedures. Data not available in the input for specific payor policies, associated taxonomies, ICD-10 diagnoses, and related codes.