Frequently Asked Questions

An ambulatory surgery center — also called an outpatient surgery center or same-day surgery center — is a licensed medical facility where patients have elective surgical or diagnostic procedures performed and go home the same day. ASCs are freestanding facilities, separate from hospitals, and are specifically designed for outpatient care. They perform millions of procedures every year across specialties including ophthalmology, gastroenterology, orthopaedics, ENT, and pain management.

Both settings perform outpatient procedures, but they differ in cost, environment, and staffing. ASCs typically cost 45–60% less than hospital outpatient departments for the same procedure — a difference that shows up in both what Medicare pays and what you owe out of pocket. ASCs tend to be smaller, more focused, and often have shorter wait times and higher patient satisfaction scores. Hospital outpatient departments have more on-site emergency resources, which can matter for higher-risk patients or complex procedures.

For the procedures they perform, yes — ASCs have strong safety records. Because ASCs focus on elective, lower-risk procedures and don't treat emergency or critically ill patients, their complication rates are generally comparable to or better than hospital outpatient departments for the same procedures. All Medicare-certified ASCs must meet federal Conditions for Coverage, and accredited facilities undergo additional inspection by independent organizations like AAAHC, AAAASF, or The Joint Commission.

ASCs perform thousands of different procedures across more than 20 surgical specialties. The most common include colonoscopies and upper endoscopies (gastroenterology), cataract surgery (ophthalmology), knee and shoulder arthroscopy (orthopaedics), carpal tunnel release (hand surgery), tonsillectomies and sinus surgery (ENT), and epidural steroid injections (pain management). Advances in minimally invasive techniques have steadily expanded the range of procedures that can be safely performed in an outpatient setting.

Yes. Colonoscopies are among the most commonly performed procedures at ASCs, and the safety data is strong. Studies consistently show comparable — and often better — outcomes at ASCs for routine colonoscopy compared to hospital settings. ASC gastroenterology centers perform high volumes of these procedures, and the focused environment tends to translate to efficient, well-coordinated care. If you have significant underlying health conditions, discuss with your doctor whether a hospital setting is more appropriate.

Cataract surgery is actually one of the most common procedures performed at ASCs — and one of the safest. The procedure typically takes 15–30 minutes, is performed under local anesthesia or light sedation, and most patients go home within an hour of arriving. Ophthalmology surgery centers specialize in exactly this type of procedure and typically have very high volumes and strong patient experience scores.

Many knee procedures are well-suited to ASC settings — including knee arthroscopy, ACL reconstruction, meniscus repair, and even select knee replacements. Whether you're a candidate for outpatient knee surgery depends on your overall health, the complexity of the procedure, and your surgeon's assessment. Orthopaedic ASCs with high surgical volumes and experienced teams often achieve excellent outcomes for these procedures.

Interventional pain management ASCs perform a wide range of minimally invasive procedures for chronic pain — including epidural steroid injections, nerve block injections, radiofrequency ablation (RFA), spinal cord stimulator implants, and joint injections. These procedures are typically performed under fluoroscopic (X-ray) or ultrasound guidance. Most are done under light sedation or local anesthesia with no overnight stay required.

Yes. ENT (ear, nose, and throat) procedures are among the most common outpatient surgeries. Tonsillectomies and adenoidectomies, ear tube placement, sinus surgery (FESS), septoplasty, and laryngoscopy are all routinely performed at ASCs. Adult tonsillectomies may sometimes require overnight monitoring depending on the patient, but most ENT procedures are straightforward same-day cases.

Bring a photo ID, your insurance card, a list of all current medications (including dosages), and any pre-op paperwork or forms the facility sent you. Leave valuables at home. Most importantly, arrange for a responsible adult to drive you home and stay with you for the first several hours — ASCs will not discharge patients who don't have someone to accompany them. Wear comfortable, loose-fitting clothing that's easy to change into and out of.

Standard guidelines from the American Society of Anesthesiologists call for no solid food for at least 6–8 hours before surgery, and no clear liquids for at least 2 hours. Your ASC will give you specific instructions based on your procedure and anesthesia type — follow those instructions exactly. Arriving with food in your stomach can lead to your procedure being cancelled for safety reasons. If you take daily medications, ask your doctor or the facility whether to take them the morning of surgery with a small sip of water.

Total time at the facility is usually 2–4 hours, depending on the procedure. That includes check-in and registration, pre-op preparation (changing, IV placement, meeting with the anesthesiologist and surgeon), the procedure itself, and time in the recovery room before you're cleared to go home. Simple procedures like injections or endoscopies may have you out in under 2 hours. More involved surgeries with general anesthesia typically require longer recovery observation.

This depends on the procedure and your medical history. The three most common options at ASCs are general anesthesia (you're fully unconscious), regional anesthesia / nerve blocks (a specific area is numbed — common for hand, foot, or knee surgery), and monitored anesthesia care or MAC (light IV sedation where you're relaxed and sleepy but not fully unconscious). Your anesthesiologist will review your health history and explain the plan before the procedure.

Yes. Medicare Part B covers outpatient surgery at Medicare-certified ASCs. Medicare pays the facility a fixed ASC facility fee, which is set by CMS and is typically lower than what a hospital outpatient department would receive for the same procedure. You're responsible for the Part B deductible and 20% coinsurance after the deductible is met. If you have a Medicare supplement (Medigap) plan, it may cover some or all of that 20%.

This is normal and catches a lot of patients off guard. The ASC facility fee, the surgeon's professional fee, and the anesthesiologist's fee are billed separately because they're separate providers — even if they all work at the same location. Each bill goes through your insurance independently. Make sure all three providers are in-network before your procedure to avoid surprise out-of-network charges, especially for anesthesia.

Many procedures at ASCs require prior authorization from your insurance company before they'll cover the cost. Your surgeon's office typically handles this, but it's worth confirming it's been submitted and approved before your surgery date — not after. Authorization usually takes 3–10 business days. If your procedure is denied, you have the right to appeal, and your doctor can submit a letter of medical necessity to support the request.

OAS CAHPS (Outpatient and Ambulatory Surgery Consumer Assessment of Healthcare Providers and Systems) is a standardized patient experience survey administered by CMS. It measures how patients rate their experience across areas like communication from staff, cleanliness, pain management, and overall rating. Scores are published publicly and are one of the best tools patients have for comparing the quality of care at different ASCs. A higher score reflects better-reported patient experiences.

Accreditation means an independent, non-governmental organization has inspected the facility and verified it meets a defined set of quality and safety standards — beyond the baseline requirements for Medicare certification. The three main accreditors for ASCs are AAAHC, AAAASF, and The Joint Commission. Accreditation is voluntary, and not all quality ASCs are accredited, but it signals that a facility has undergone rigorous third-party review of its clinical practices, staff credentialing, equipment, and patient safety protocols.

A few worth asking: Is the facility Medicare-certified and accredited — and by whom? How many times has my surgeon performed this specific procedure here? What's the ASC's unplanned transfer rate to the hospital? Are all providers (surgeon, anesthesiologist) in-network with my insurance? What is the discharge process if I have a complication after I get home? What's their infection control protocol? You shouldn't feel like you're being difficult for asking — a good facility will answer these without hesitation.