Ambulatory Surgery Centers

views updated

Ambulatory Surgery Centers

Historical background
Advantages of ASCs
ASCs within the American health care system
Legal and regulatory issues


Ambulatory surgery centers (ASCs) are medical facilities that specialize in elective same-day or outpatient surgical procedures. They do not offer emergency care. The word ambulatory comes from the Latin verb ambulare, which means “to walk.” It means that the patients treated in these surgical centers do not require admission to a hospital and are well enough to go home after the procedure. Ambulatory surgical centers are also known as surgicenters.


As of 2008, there were more than 5,300 ambulatory surgical centers in the United States, up from about 3,700 in 2003. In 1980, only 275 such centers existed. This rapid increase reflects a general trend toward surgeries performed on an outpatient basis. According to American Medical News, 70% of all surgical procedures performed in the United States in 2000 were done in outpatient facilities, compared to 15% in 1980. As of 2003, over seven million surgeries are performed annually in American ASCs. Between 1990 and 2000, the number of operations performed annually in these centers rose 191%, from 2.3 million procedures in 1990 to 6.7 million in 2000.

The types of surgical procedures performed in ASCs have also undergone significant changes in recent years. Many of the early ASCs were outpatient centers for plastic surgery. Advances in minimally invasive surgical techniques in other specialties, however, led to the establishment of ASCs for orthopedic, dental, and ophthalmologic procedures. According to the Federated Ambulatory Surgery Association (FASA), gastroenterology accounted for only 10% of all procedures performed in ASCs in 1995, while plastic surgery still represented 20%. These proportions changed rapidly. By 1998, only three years later, ophthalmology accounted for more procedures performed in ASCs than any other surgical specialty (26.8%), followed by gastroenterology (18.8%), orthopedic surgery (9.8%), gynecology (9.5%), plastic surgery (7.7%), and otolaryngology (6.9%). The remaining 20.6% included dental, urological, neurological, podiatric, and pain block procedures.

As of 2003, ASCs are not distributed evenly across the United States; they tend to be concentrated in urban areas, particularly those with a high ratio of physicians to the general population.


Ambulatory surgical centers are sometimes classified as either hospital-associated or freestanding. The term freestanding is somewhat confusing because some hospital-associated ASCs are located in buildings that may be several blocks away from the main hospital. As


Ambulatory— Referring to a condition that is treatable without admission to a hospital, or to a surgical procedure performed on an outpatient basis.

Dedicated— Reserved for a specific purpose. An ambulatory surgical center must have at least one dedicated operating room in order to qualify for accreditation.

Elective— Referring to a surgical procedure that is a matter of choice; an elective operation may be beneficial to the patient but is not urgently needed.

Podiatry— The surgical specialty that treats disorders of the foot.

Surgicenter— Another term for ambulatory surgical center.

a result, some states have defined an ASC for legal purposes as “a facility primarily organized or established for the purpose of performing surgery for outpatients and…a separate identifiable legal entity from any other health care facility.” More recently, some ASCs have sought institutional relationships with academic medical centers, hoping to benefit from the prestige associated with teaching and research.

Ambulatory surgery centers should not be confused with office-based surgery practices or with other outpatient centers that provide diagnostic services or primary health care, such as urgent care centers, community health centers, mobile diagnostic units, or rural health clinics. ASCs are distinguished from these other health care facilities by their use of a referral system for accepting patients and their maintenance of a dedicated operating room. The first characteristic means that any patient who wants to be treated in an ambulatory surgery center must first consult their primary health care provider, or PCP, and choose to have their condition treated by surgery rather than an alternative approach. The second feature means that the surgical facility must have at least one room that is used only for operations.

Accreditation and ownership

The Joint Commission on Accreditation of Healthcare Organizations (JCAHO) lists nine types of ASCs that it presently accredits:

  • cosmetic and facial surgery centers
  • endoscopy centers
  • ophthalmology practices
  • laser eye surgery centers
  • centers for oral and maxillofacial surgery
  • orthopedic surgery centers
  • plastic surgery centers
  • podiatry clinics
  • multi-specialty surgery centers

Medicare inspection and certification of ambulatory surgery centers is a separate process from professional accreditation. An ASC does not have to be certified by Medicare in order to be accredited by JCAHO. Office-based surgical practices are accredited by JCAHO under a specialized Office-Based Surgery Accreditation program.

ASCs are sometimes categorized on the basis of ownership. Some are owned by hospitals and others are owned by the physicians who treat patients in them; about half, however, are operated by investor-owned businesses. The rapid growth of ASCs is in part a reflection of the general commercialization of health care in the United States over the past two decades.

Patient care

A patient in an ambulatory surgical center is asked to observe some of the same precautions and preparations that hospital patients undergo, including routine blood tests and a thorough medical history to make certain that they will not have an adverse reaction to anesthesia. In most cases the patient will be told to avoid eating and drinking before the procedure. Patients are asked to have a friend or family member drive them home after surgery; some ASCs request that the friend or relative come with the patient in the morning and stay at the center in a waiting area until the patient feels well enough to leave.

On average, patients leave the ASC within two hours after their surgery. If the patient needs overnight care or has a serious complication, he or she is transferred to an acute care hospital. Most ASCs that are not hospital-owned have arrangements with nearby hospitals to cover emergency situations.

Historical background

The first ambulatory surgical center was opened in 1970 by a group of anesthesiologists in Phoenix, Arizona. Relatively few ASCs were built, however, until the mid-1980s. Two factors that encouraged the rapid spread of ASCs after that point were the development of accreditation programs and standards on the one hand and government approval on the other. In 1980 the American Society of Plastic and Reconstructive Surgeons (ASPRS) established the American Association for Accreditation of Ambulatory Plastic Surgery Facilities, or AAAAPSF, in order to guarantee the quality of outpatient surgical facilities. The AAAAPSF then formed the American Association for Accreditation of Ambulatory Surgical Facilities, or AAAASF, to establish standards for single-specialty and multi-specialty ASCs owned or operated by surgeons who are board-certified in other types of surgery. In 1982 procedures performed at ASCs were made eligible for Medicare payments on the grounds that they were low-risk surgeries provided in less expensive settings. As of 2003, 85% of the ASCs in the United States are certified by Medicare.

Other factors involved in the expansion of ASCs include:

  • Advances in medical technology. The development of instruments that made minimally invasive procedures possible made certain types of surgery less complicated to perform and less painful for the patient. The most important single development that made outpatient surgery increasingly safe, however, is the discovery of new anesthetic agents combined with better techniques for administering anesthesia. The number of anesthesia-related deaths has dropped sharply since the 1980s, from 1:10,000 operations in 1982 to 1:400,000 in 2002.
  • Demographic changes. Instead of a shortage, by the late 1990s there was an oversupply of physicians as well as hospital beds in the United States. This situation has led to increasing competition for patients among both doctors and hospital managers.
  • The increasing commercialization of health care. The rise of investor-owned hospitals and ambulatory surgery centers encouraged many doctors to invest money in these facilities, particularly the ASCs. Since ambulatory surgery centers accept patients only on a referral basis, questions have been raised about the legitimacy of doctors referring patients to facilities in which they have a financial interest. The former editor of the New England Journal of Medicine cites a Florida study revealing that almost 40% of the doctors practicing in that state had money invested in the ASCs to which they sent their patients.

Advantages of ASCs

Surgeons as well as patients tend to prefer ambulatory surgery centers for outpatient procedures for several reasons:

  • Cost. In many cases, an outpatient procedure done in an ASC costs between one-half and one-third as much as the same procedure done in a hospital. It is important, however, for patients to compare costs carefully, because some ASC procedures may cost as much as or even more than hospital-based procedures. For example, the Medicare Payment Advisory Commission found that whereas a cataract operation cost only $942 at an ambulatory surgery center in 2001 as opposed to $1334 at a hospital, after-cataract laser surgery cost $429 at the ASC versus $246 at a hospital. Figures for an endoscopy and biopsy of the upper digestive tract were $429 and $359 respectively; for a diagnostic colonoscopy, $429 and $401; and for epidural anesthesia, $320 and $183.
  • Convenience. There is much less administrative paperwork and “red tape” at an ambulatory surgical center compared to the admissions process at most hospitals. Patients also like the fact that they can leave an ASC relatively quickly after their surgery, which translates into less time lost from work.
  • Presence of family and friends. Whereas most hospitals keep patients recovering from a surgical procedure in separate rooms, in an ASC the patient can usually spend the recovery period after surgery with their loved ones.
  • Greater efficiency. This advantage is particularly important to surgeons. It takes much less time to prepare an operating room in a specialized ASC for the next patient than in a standard hospital. Improved efficiency allows the surgeon to treat more patients in the same amount of time than he or she would be able to do in a hospital; some surgeons maintain that they can do three times the number of procedures in an ASC as they could in a hospital setting.
  • Greater control over procedures and standards. Many doctors prefer working in an ASC because they can set the standards for staffing, safety precauions, postoperative care, etc., rather than having these things decided for them by a hospital manager.

ASCs within the American health care system

As of 2003, there are several areas of tension in the health care system related to ambulatory surgical centers. One is opposition from hospitals. Most hospitals have relied on income from surgical procedures to make up for losses incurred by treating other patients who cannot afford to pay. The movement toward freestanding ambulatory surgery centers means a considerable loss of income for many hospitals.

On the other hand, there is also increasing competition between ASCs and office-based surgical practices. The same improvements in anesthesia and surgical equipment that made outpatient surgery in an ASC safe to perform have also made it safe to do a growing number of fairly complex procedures in a doctor’s office. Such procedures as hernia repair, arthroscopic joint repair, and liposuction are now being performed in office-based facilities. It is estimated that by 2005, 10 million surgical procedures will be performed annually in American doctors’ offices, or twice as many as were done in 1995. The American Society of Anesthesiologists predicts that office-based surgical procedures will account for a steadily growing proportion of outpatient surgeries. The ASA has stated that “…the trend toward office-based surgery is growing at least as fast [as of 2003] as the trend toward ambulatory surgery grew a few years ago.”

Legal and regulatory issues

The growing number of for-profit ASCs as well as government involvement with outpatient facilities through the Medicare program has led to a number of legal and regulatory questions. One issue concerns the level of Medicare reimbursement for procedures performed in ASCs. The present Medicare fee schedule is based on data from 1986, when the operating costs of many ambulatory surgical centers were higher than they are in 2003, due to advances in technology. As a result, some observers think that ASCs are being overpaid for services to Medicare patients. Another issue is a proposal to add more procedures to the list approved by Medicare for ASC patients. The present list has not been updated since 1995. The proposed additions would increase ASC services available to Medicare patients by 20%.

The major legal question facing surgeons who own or have investments in ambulatory surgical centers is whether they are breaking the law by referring patients to ASCs in which they have invested or in which they perform surgery. The existing laws are not entirely clear on this point, but experts in health law do not expect the confusion to be resolved in the near future.



Aker, J. “Safety of Ambulatory Surgery.” Journal of Perianesthesia Nursing 16 (December 2001): 353–358.

Baker, J. J. “Medicare Payment System for Ambulatory Surgical Centers.” Journal of Health Care Finance 28 (Spring 2002): 76–87.

Becker, S. and M. Biala. “Ambulatory Surgery Centers—Current Business and Legal Issues.” Journal of Health Care Finance 27 (Winter 2000): 1–7.

Becker, S. and N. Harned. “The Fraud and Abuse Statute and Investor-Owned Ambulatory Surgery Centers.” Health Care Law Monthly (April 2002): 13–23.

Hawryluk, Markian. “Ambulatory Surgery Centers’ Medicare Pay Rate Questioned.” American Medical News November 25, 2002 [cited March 12, 2003].

Jackson, Cheryl. “Cutting Into the Market: Rise of Ambulatory Surgical Centers.” American Medical News, April 15, 2002. [cited March 12, 2003].

Lynk, W. J. and C. S. Longley. “The Effect of Physician-Owned Surgicenters on Hospital Outpatient Surgery.” Health Affairs (Millwood) 21 (July-August 2002): 215–221.

Mamel, J. J. and H. J. Nord. “Endoscopic Ambulatory Surgery Centers in the Academic Medical Center. We Can Do It Too!” Gastrointestinal Endoscopy Clinics of North America 12 (April 2002): 275–284.

O’Brien, D. “Acute Postoperative Delirium: Definitions, Incidence, Recognition, and Interventions.” Journal of Perianesthesia Nursing 17 (December 2002): 384–392.

Relman, Arnold S., MD. “Canada’s Romance with Market Medicine.” American Prospect 13 (October 21, 2002) [cited March 12, 2003].

Relman, Arnold S., MD. “What Market Values Are Doing to Medicine.” Atlantic Monthly 269 (March 1992): 99–106.


Accreditation Association for Ambulatory Health Care (AAAHC). 3201 Old Glenview Road, Suite 300, Wilmette, IL 60091-2992. (847) 853-6060.

American Association for Accreditation of Ambulatory Surgery Facilities (AAAASF). 1202 Allanson Road, Mundelein, IL 60060. (888) 545–5222.

American Association of Ambulatory Surgical Centers (AAASC). P. O. Box 23220, San Diego, CA 92193. (800) 237-3768.

American Health Lawyers Association. Suite 600, 1025 Connecticut Avenue NW, Washington, DC 20036-5405. (202) 833-1100.

American Society of Anesthesiologists (ASA). 520 N. Northwest Highway, Park Ridge, IL 60068-2573. (847) 825-5586.

Federated Ambulatory Surgery Association (FASA). 700 North Fairfax Street, #306, Alexandria, VA 22314. (703) 836-8808.

Joint Commission on Accreditation of Healthcare Organizations (JCAHO). One Renaissance Boulevard, Oakbrook Terrace, IL 60181. (630) 792-5000.


American Society of Anesthesiologists. Office-Based Anesthesia and Surgery. [cited March 13, 2003].

Rebecca Frey, Ph.D.

Ammonia (blood) test seeLiver function tests