2. You save time: The bureaucracy of a hospital makes delays a fact of life. In an office, the doctor is in control, so surgeries typically start when they're supposed to.

3. You're exposed to fewer germs: Some 1.7 million infections occur in U.S. hospitals each year, including those caused by superbugs such as MRSA or C. diff, which are resistant to common antibiotics. Doctors' offices typically aren't breeding grounds for these types of bacteria in part because the very sick patients who harbor and spread them don't spend as much time there.

A Double-Edged Scalpel

Yet OBS has its drawbacks. One of the biggest is that because it's less heavily regulated than hospital-based procedures, it can involve additional risks for patients. "In many states, OBS is overseen by a medical board, and boards tend to be dominated by physicians, as opposed to the more consumer-focused state health departments that supervise hospitals and freestanding ambulatory surgery centers," Kulczycki says. When Vila examined data from the two years before Florida tightened its OBS regulations, he found that for every 100,000 OBS procedures, 66 serious complications and nine deaths occurred—a rate about 12 times higher than in the state's outpatient surgery centers.

Some states are working to implement greater oversight: In 2007, after a series of incidents including the death of a 42-year-old mother after having a facelift in a plastic surgeon's office, New York State passed one of the country's strictest laws governing OBS. Physicians using more than minimal sedation in offices there must now have much of the same safety equipment found in a hospital OR, they must report all serious complications to the department of health, and, most important, their offices must be inspected and accredited by an independent organization every three years. Doctors who don't comply risk losing their licenses. (Nearly 800 offices have been accredited since the law's passage.)

Still, 25 states don't regulate OBS facilities (to find out whether yours does, see, and patients who have surgery there are left without adequate government protection. Some of the risks:

1. The state doesn't check the doctor's credentials: Before being allowed to operate in a hospital or regulated OBS facility, doctors must provide proof of advanced training in their specialty. Not so with an unaccredited or unlicensed office: Any MD can legally hang out a shingle advertising a procedure he may not be properly trained to perform.

2. Trained anesthesiologists may not be present: With local anesthesia, this usually is not an issue, but it is a serious omission with more potent drugs, since the risk of respiratory or cardiac arrest is very real. (One in 200,000 patients dies on an operating table each year from a reaction to anesthesia.) "Some physicians think they can handle both the operation and the sedation, but it would be tough for a surgeon to manage complications on both fronts," says Richard Swanson, MD, a surgical oncologist at Brigham and Women's Hospital and chair of the American College of Surgeons' OBS committee.

Two more risks, plus 6 questions you need to ask before making your decision
As a reminder, always consult your doctor for medical advice and treatment before starting any program.