Ambulatory surgery centers


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 2003, there are about 3,700 ambulatory surgical centers in the United States, compared with 275 in 1980 and 1,450 in 1990. 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 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:

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:

Advantages of ASCs

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

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.

See also Hospital services ; Medicare ; Outpatient surgery .



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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.

User Contributions:

Patricia Connor
I had Breast Reconstruction at Tribeca Plastic Surgery in NY, NY by Dr. Sydney Coleman. His facility is AAAASF rated and it is ambulatory outpatient. I need the CPT code for insurance. If you cannot respond to me could you email his staff who cannot locate the CPT code at
Never would have thunk I would find this so idnisepnsbale.
i have any question
1) are There number of inpatient beds in each ambulatory surgical center ?
2)are there of man power (staff) work in each ambulatory surgical center ?
3)What is the area in each ambulatory surgical center ?
thanke you for your attention
best regurd
hamidreza khesali MD

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