CPT code 61684 defines a neurosurgical craniotomy and resection of a simple infratentorial arteriovenous malformation (AVM) — specifically a lesion 3 cm or smaller, readily accessible, without deep venous drainage or involvement of eloquent cortical areas. This procedure represents a high-complexity operative service within neurosurgery and is significant nationally due to its association with specialized surgical teams, facility resource use, and potential for substantial variability in payer coverage and authorization requirements. Key payers addressed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise clinical and billing context for CPT code 61684, including typical site of service and service-line designation; a summary of common modifiers encountered in neurosurgical operative billing; and where available, payer coverage patterns and authorization considerations. The publication highlights benchmarks and policy updates relevant to complex cranial procedures, outlines clinical indications implicit in the code description, and identifies gaps where diagnosis coding and taxonomy mappings are not provided. Data not available in the input are explicitly noted.