- Two physicians opened the first ASC in 1970 on the idea that surgery didn't require a hospital stay. Today more than 6,600 Medicare-certified ASCs operate across the country.
- Medicare's ASC Covered Procedures List (ASC-CPL) grew from about 200 in 1982 to more than 3,500 by 2011, and it continues to grow.
- Recent Medicare rules have greatly expanded the ASC-CPL. The 2027 proposed rule continues CMS's three-year phaseout of the inpatient-only list, with nearly 640 services proposed for removal and 618 codes proposed for the ASC-CPL.
- ASCs saved Medicare $5.1 billion in 2024 alone, and that figure is projected to reach $12.5 billion annually by 2034.
- Industry forecasts project ASC volume will grow 24% over the next decade, led by orthopedics, gastroenterology, ophthalmology, and general surgery.
August marks National ASC Month, providing an opportunity to recognize the ambulatory surgery centers, physicians, and clinical staff dedicated to expanding access to high-quality, cost-efficient outpatient surgical care. As the healthcare industry continues to spotlight the essential role ASCs serve within the broader ecosystem, how can your facility leverage this momentum to drive operational and financial performance? This occasion allows leaders to evaluate the evolution of the ASC model — from its inception to its current state — and identify the innovations that will shape the next generation of surgery center management.
A Better Way, Built From Scratch
In 1970, if you needed surgery, you went to a hospital. You generally waited weeks or months for the appointment, and you often stayed several days afterward to recover.
Two physicians, Wallace Reed and John Ford, thought patients deserved something better. They spent two years lining up endorsements and financing for a facility that didn't exist yet: freestanding, built for one purpose, designed to get patients through surgery and home the same day.
On Feb. 12, 1970, that facility opened in Phoenix under the name Surgicenter. Five physicians performed five procedures that day, four of them under general anesthesia. The idea spread fast. According to the Ambulatory Surgery Center Association's (ASCA) history of the ASC industry, 42 surgery centers were operating in the United States by 1975, with 25 more opening the year after that.
The rest of the industry's structure built up around that early momentum. The American Medical Association endorsed outpatient surgery in 1971. The American Society of Anesthesiologists published its first set of ASC guidelines in 1973. Accrediting bodies, including The Joint Commission's ambulatory care program and the Accreditation Association for Ambulatory Health Care, followed by the end of the decade, as ASCA's timeline lays out. Physicians proved the model worked case by case, and the accreditation and standards followed.
Earning Trust, Procedure by Procedure
Medicare made the ASC model official in 1982, approving payment for roughly 200 procedures. From there, the ASC Covered Procedures List (ASC-CPL) grew. ASCA's timeline puts the total at 1,535 procedures by 1987, more than 2,000 by 1995, and more than 3,500 by 2011. Every expansion followed the same pattern: Physicians took on a new category of case, the outcomes held up, and the Centers for Medicare & Medicaid Services (CMS) eventually opened the door for ASCs a little wider.
The industry's infrastructure caught up along the way. In 2008, the two founding trade groups, the Federated Ambulatory Surgery Association (FASA) and the American Association of Ambulatory Surgery Centers (AAASC), merged to form ASCA, giving the industry one voice in the nation's capital. By 2010, the number of accredited ASCs had passed 5,000. Today, ASC Data counts more than 6,600 Medicare-certified ASCs operating across the country.
The ownership structures behind those centers have grown more varied as the industry has matured. Some ASCs remain wholly physician owned. Others operate as partnerships between physicians and hospitals, health systems, or academic medical centers, and others as partnerships between physicians and management companies. Additional owner and operator models exist. Different markets and specialties have leaned on whichever structure fits, and that flexibility has helped the model scale.
MedPAC's latest report to Congress shows the number of Medicare-certified ASCs increased more than 2% a year on average between 2019 and 2024. Volume per Medicare beneficiary rose 3.5% in 2024 alone, and fee-for-service Medicare payments to ASCs reached $7.5 billion, up from $5.3 billion in 2019. The financial value ASCs deliver to the healthcare system has held up right alongside the growth of payments. A recent KNG Health Consulting analysis, covered by ASC Focus, found ASCs saved Medicare $5.1 billion in 2024, with savings projected to grow to $12.5 billion a year by 2034, nearly $85 billion over the coming decade. Medicare pays ASCs roughly half of what it pays hospitals for the same procedures, so essentially every case that moves to the ASC setting is money saved for the program and the patient.
The ASC Story Keeps Accelerating
The last two years show how much the ASC industry's pace has picked up and why the future looks so bright. CMS's 2026 final rule added nearly 550 codes to the ASC-CPL, one of the largest single-year expansions in the program's history, and kicked off a three-year phaseout of the inpatient-only (IPO) list.
This year's proposed rule continues that phaseout. CMS is proposing to remove nearly 640 services from the IPO, more than double the 285 codes removed in the first year of the phaseout, and add 618 codes to the ASC-CPL. The procedures on this year's list are also a step up in complexity: laparoscopic colectomy, partial nephrectomy, sleeve lobectomy, prostatectomy. A few years ago, most people would have assumed these only belonged in a hospital.
Where This Is Headed
Gastroenterology and ophthalmology remain the largest ASC specialties nationally, but the fastest growth is happening elsewhere. From 2023 to 2024, cardiology grew faster than nearly every other specialty, trailing orthopedics, continuing a trend that made cardiology one of the industry's fastest-growing specialties in recent years. A 2026 forecast from Vizient, reported by ASC Focus, picks up the same thread, naming cardiovascular care as the next frontier for ambulatory surgery as CMS continues to expand which cardiac procedures can be performed in an ASC.
That same Vizient forecast projects ASC volume will grow 24% over the next decade, led by orthopedics, gastroenterology, ophthalmology, and general surgery. Vizient's own analysts caution that the pace won't be even everywhere. Physician alignment, payer dynamics, state regulation, and local competition will all shape how fast a given market shifts. But the direction has held steady since 1970. More procedures move into the ASC setting as the evidence supports it.
Proud to Be Part of It
Fifty-plus years in, the case ASCs have been making since Phoenix keeps proving out, case by case.
SIS has spent three decades working alongside surgical providers and ASCs through that story, building the systems that today help thousands of centers nationwide take on more complex cases, protect their revenue, and stay compliant as the case mix keeps changing. Operate Smart is what we call that partnership, and it's the same principle the industry has run on since 1970.
