E&M services within the 90 day global period in dialysis access creation and maturation: Part 1

Question: If a staged procedure is proposed for creation of dialysis access (e.g., a preliminary AV fistula followed by superficialization or transposition) can a E&M service with supporting ultrasound be billed at the follow-up visit within the 90 global period when the patient is advised to have the second procedure? This assumes that progress of the preliminary fistula must be assessed for adequate maturation and size prior to the decision for second surgery. If so, would it be billed with 24 modifier or 57 modifier, or both?