Assistants-at-surgery, who serve as members of surgical teams, perform tasks under the direction of surgeons and aid them in conducting operations. These tasks may include making initial incisions (“opening”), exposing the surgical site (“retracting”), stemming blood flow (“hemostasis”), surgically removing veins and arteries to be used as bypass grafts (“harvesting”), reconnecting tissue (“suturing”), and completing the operation and reconnecting external tissue (“closing”). Some of these tasks, like retraction, are relatively simple, while others, such as harvesting, are more complex. An assistant-at-surgery may perform one or more simple or complex tasks during an operation. Tasks performed by others on the surgical team differ from those performed by assistants-at-surgery. Scrub staff work within the sterile field—the area within the operating room that is kept free from harmful microorganisms—passing instruments, sponges, and other items directly to the surgeon and assistant-at-surgery who work within the sterile field. Circulators work outside the sterile field, responding to the needs of team members within the sterile field. Anesthesiologists, or anesthetists, who administer and monitor anesthesia, painkillers, and other drugs, are also present during an operation. Decisions by a hospital or surgeon to use an assistant-at-surgery depend on the complexity of the operation and medical condition of the patient. Physician associations, such as the ACS and the American Society of General Surgeons, maintain that the surgeon should be responsible for determining if an assistant-at-surgery is needed, although some hospitals require the use of an assistant for certain surgical procedures. Hospitals that employ assistants-at-surgery may assign them to a procedure without consulting the surgeon performing the procedure. Since 1994, the ACS, with other surgical specialty organizations, has conducted studies to determine which surgical procedures require physicians as assistants-at-surgery. These studies classify surgical procedures as “almost always,” “sometimes,” or “almost never” requiring an assistant-at-surgery. The 2002 study classifies approximately 5,000 surgical procedures, about 1,750 of which are designated as “almost always” requiring a physician to serve as an assistant-at-surgery. A small number of surgical procedures have accounted for the majority of the assistant-at-surgery services paid for under the Medicare physician fee schedule: In 2002, 100 procedures accounted for almost 75 percent of the assistant-at-surgery services that Medicare paid under the physician fee schedule. ACS designated 81 of these procedures as “almost always” requiring a physician as an assistant-at-surgery, and the remaining 19 procedures were designated as “sometimes” requiring a physician as an assistant. Medicare pays for medically necessary services, including those performed by assistants-at-surgery, for eligible elderly and disabled patients provided by health professionals and institutions meeting certain requirements. Part A, or Hospital Insurance, pays for inpatient hospital care, care provided by certain other health care facilities, and some home health care. Part B, or Supplementary Medical Insurance, includes payment for the services and items provided by physicians, certain other nonphysician health professionals, suppliers, outpatient hospital departments, and home health care agencies. Medicare makes payments to hospitals under part A through the hospital inpatient PPS for assistants-at-surgery. A fixed payment is made for all the inpatient hospital services, including assistant-at-surgery services, that a hospital provides to a beneficiary with a given diagnosis or receiving a particular type of surgery. Payments under the hospital inpatient PPS reflect the average bundle of services that beneficiaries with a particular diagnosis receive as inpatients in similar hospitals. The hospital’s payment for a bundle of services is the same regardless of whether an assistant-at- surgery is used or who provides the assistant-at-surgery services. Prospective payment systems, such as the hospital inpatient PPS, are designed to promote efficiency: because the payment for a particular bundle of services is almost always the same, regardless of the services a particular patient receives, hospitals are discouraged from providing unnecessary services. Providing additional services would not increase their payments. Consequently, PPS payments to the hospital are sometimes less and sometimes more than the cost of providing care. Payments are also made under the hospital inpatient PPS to teaching hospitals for providing GME to the residents employed by the hospital. In 2001, about 20 percent of the approximately 5,800 U.S. hospitals were considered teaching hospitals. In 2003, surgical residents comprised about 20 percent of all residents at these hospitals. There were about 7,500 residents in general surgery and about 13,000 more surgical residents training for specialties, such as orthopedics, all of whom were required to serve as assistants-at-surgery as part of their training. In addition to these surgical residents, some nonsurgical residents have surgical rotations during which they serve as assistants-at-surgery. Medicare makes part B payments to assistants-at-surgery under the physician fee schedule when assistant services are performed by a physician or by a nonphysician health professional authorized to receive such payment. In 2002, these payments totaled about $158 million, less than 2 percent of the $10.5 billion Medicare paid to surgeons for surgical procedures that year. Medicare also makes global payments to surgeons under the physician fee schedule that cover the surgery and some pre- and postoperative services that the surgeons and their employees perform. Assistant-at-surgery services are not included in this bundle of services. Generally, the amount Medicare pays under the physician fee schedule is based on the resources needed to perform a service: the physician’s time and skill, practice expenses that include the costs of staff, equipment, and supplies, and the cost of liability insurance. While a surgeon’s global fee for a surgical procedure is set to reflect the resources required to perform the service, payments under the physician fee schedule for assistant-at- surgery services are not; they are calculated as a fixed percentage of the surgeon’s global fee. The percentage varies depending on the profession of the assistant-at-surgery. The Medicare physician fee schedule pays physicians more than nonphysician health professionals for assistant-at- surgery services (see table 1). Medicare sets requirements that various health care institutions, suppliers, and professionals must meet to be paid by the program. Institutions, such as hospitals, must meet conditions of participation (CoP)—health and safety rules used to ensure quality of care. Until 1986, HCFA specified some requirements for assistant-at-surgery services in its hospital CoP. Hospitals were required to have physicians serve as assistants-at-surgery for procedures “with unusual hazard to life,” while “nurses, aides, or technicians having sufficient training to properly and adequately assist’’ could assist at “lesser operations.” In a broad revision of the hospital CoP in 1986, the agency eliminated these requirements: it said the purpose of the revisions to the surgical services section, which had included the assistant-at-surgery requirements, was to “delete the overly prescriptive details” about the operation of surgical services. CMS retains requirements for other surgical team members, including scrub and circulating staff. CMS also establishes regulatory requirements for the health professions eligible to receive payment under the Medicare physician fee schedule. Members of that profession can be paid for providing covered services, including assistant-at-surgery services. Although CMS’s rules include the minimum requirements that these professionals must meet to receive payment for services, there are no specific requirements to receive assistant-at-surgery payments in Medicare regulations. General requirements include education, licensure, and certification; no surgical education or experience is mandated. For example, physician assistants must graduate from an accredited physician assistant education program, pass the National Commission on Certification of Physician Assistants certification examination, and be licensed to practice as a physician assistant, but do not have to have experience as an assistant-at-surgery. Members of a wide range of health professions serve as assistants-at- surgery. Hospitals employ residents, international medical graduates, and all the types of nonphysician health professionals who perform the role. Hospital employees likely serve as assistants-at-surgery for a majority of the procedures for which the ACS says an assistant is “almost always” necessary. The number of assistant-at-surgery services performed by physicians and paid for under the physician fee schedule has declined, while the number of such services performed by nonphysician health professionals eligible to receive payment under the physician fee schedule has increased. Physicians, residents in training for licensure or board certification in a physician specialty, several different kinds of nurses, and members of several other health professions serve as assistants-at-surgery (see table 2). Surgical associations state that surgeons or residents are preferred as assistants-at-surgery, but surgeons are often not available to assist at surgery. Hospitals employ the gamut of health professionals who serve as assistants-at-surgery to perform the role. Some hospitals tend to hire assistants-at-surgery from a particular health profession, sometimes offering training courses in assistant services for that profession, to ensure that the hospital has a sufficient number of assistants. To encourage surgeons to use their operating rooms, hospitals may (1) employ assistants-at-surgery, eliminating the need for the surgeons to hire their own assistants, or (2) arrange for health professionals in independent practice to serve as assistants. While teaching hospitals use residents as assistants-at-surgery, these hospitals may also hire nonphysician health professionals to perform the role. In a recent survey of neurosurgery residency program directors, nearly all cited the need to hire nonphysician health professional staff, such as physician assistants, in response to the weekly 80-hour work limit for residents. Teaching hospitals with other surgical specialty programs may also need to hire nonphysician health professionals as assistants-at- surgery because of the limit on resident hours.