IN 2000 THE U.S. FOOD AND DRUG ADMINISTRATION APPROVED THE FIRST complete robotic surgery system, a four-armed, multimillion- dollar behemoth called the da Vinci. Since then, the technology has become commonplace. “A robotic prostatectomy for prostate cancer is now the standard of care,” says Michael Palese, chairman of urology at Mount Sinai Beth Israel Hospital in New York City, noting that nine out of 10 prostatectomies are now performed robotically.

Twelve years ago, Proto asked whether the technology would ever improve on the skill, technique and experience of un-assisted human hands (“The Robot Surgeon,” Winter 2007). “It’s great to have new technology,” said the late Lawrence Cohn, former chief of cardiac surgery at Brigham and Women’s Hospital, “but at the end of the day, you’d better have at least as good a result as you did with the old technique, or you’re just kidding yourself.”

Dozens of studies have tried to compare the outcomes of robotic surgery and traditional surgery, but many questions remain. One issue is that research into the technology often involves physicians with a vested interest in the success of surgical robots. A review published in the March 2019 issue of Annals of Surgery, for instance, looked at 33 major studies, more than half of which reported positive results for robotic surgery. But nearly all of that published work included authors who received money from robotic surgery companies. Researchers who got more than $9,550 were more than twice as likely to report the beneficial outcomes of robotic surgery compared to researchers who received less money, the authors found.

Economic motives aside, the expertise required to guide robotic surgery may itself constitute a research bias. “Many studies are done by single centers with considerable experience,” says surgeon Kyle Sheetz at the University of Michigan’s Center for Healthcare Outcomes and Policy in Ann Arbor, “but their outcomes may not be generalizable to surgeons across the country, who are familiar with the devices to varying degrees.”

In other words, surgeons who have done only a few supervised operations with robotic devices may be allowed to do procedures on their own, and their results might not match those in the journals, performed by robot-savvy surgeons, Sheetz notes. In a letter published in JAMA in April, he recommended that hospitals and institutions establish more rigorous credentialing requirements.

There may also be issues with the kinds of surgery the robots perform. In February the FDA sent a special alert stating that the safety and effectiveness of robotic surgery for cancer treatment, including mastectomies, “has not been established,” and noted that preliminary evidence might link it to shorter survival with some cancers. An international trial published in The New England Journal of Medicine last October found that cancer-related hysterectomy via minimally invasive robot-assisted or laparoscopic surgery was associated with lower three-year survival rates compared to open surgery. And even though some hospitals have begun using robots for minimally invasive mastectomies, there have been no clinical trials establishing that the robotic version of the procedure is more beneficial for patients than conventional surgery.

In other cases, robotic procedures may be as effective as laparoscopic surgery, but introduce higher price tags because hospitals must buy and maintain the expensive machines. A 2017 JAMA study involving nearly 24,000 patients who had undergone a kidney removal found that using robotics didn’t introduce any complications, but it did affect costs: Robotic surgery added an average of around $3,000 per patient.

Whatever its dangers or merits, robotic surgery is not going away anytime soon. As of the end of last year, 3,196 da Vinci machines have been installed in the United States, each at a cost of up to $2.5 million, and at least four other robot systems are scheduled to debut as early as this year. Michael Palese at Mount Sinai is optimistic that robotic surgery will continue to evolve. “As competition increases, costs will come down,” he says. “And the techniques, and the surgeons who use them, will keep improving.”