CPT code 45999 is an unlisted procedure code used to report surgical procedures on the rectum that lack a specific CPT descriptor. As an unlisted code, 45999 matters nationally because it requires additional documentation to explain the clinical work performed and justify payment, and it is commonly used when novel or uncommon rectal procedures are performed.

Key payers in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of how 45999 is reported, the clinical contexts that commonly prompt its use, and the administrative requirements that typically accompany unlisted procedure codes, such as detailed operative reports and rationale for code selection.

The publication presents benchmarks for reporting frequency and payment handling where available, highlights relevant policy and documentation considerations for payers and providers, and summarizes the clinical settings in which the code appears (operating room and ambulatory surgical center). Data not available in the input is noted explicitly where applicable.