Researchers say robotic surgery isn't necessarily better. (U.S. Army photo by Staff Sgt. Bernardo Fuller)

You might have heard of the medical arms race in health care — hospitals investing millions of dollars in new, unproven technologies to beat local competition in the ongoing effort to attract higher-paying patients. Hospitals then advertise the new technologies to demonstrate how great their facilities are, and neighboring hospitals feel the pressure to respond.

A new study illustrates the effect of this medical arms race through the early adoption of surgical robots. Hospitals were more likely to acquire a surgical robot — costing about $1.5 million, plus about $140,000 in annual upkeep costs — if their neighbors also had one, according to a study from a group of private and government researchers published in this month's Healthcare journal (h/t Paul Levy).

The researchers examined 552 hospitals across seven states that they determined were the most likely candidates to buy a surgical robot. Between 2001 (when federal regulators approved the technology) and 2008, 135 hospitals (24 percent) had acquired at least one surgical robot, with adoption rates jumping after 2005. The researchers found that hospitals were, in fact, more likely to acquire a surgery robot if their nearest neighbor had one.

The researchers note limitations, particularly in defining neighborhoods and identifying whether a hospital's closest neighbor actually competed for the same patients. But their study indicates, they write, "that the diffusion of new medical technology may be driven at least in part by competition among neighboring hospitals rather than solely by the mission to provide optimal patient care."

There's an easier-to-make an argument for investing in new, expensive technology if it leads to better health outcomes. However, the study authors point out that the research so far on the robots' performance has shown mixed results.

The most recent study on the topic, published in the New England Journal of Medicine last week, found that robots weren't any better at avoiding complications than traditional surgeons during procedures to remove a cancerous bladder. Those study authors said their initial findings, which looked at just the experience of Memorial Sloan Kettering Cancer Center in New York, highlight the need for a better understanding of the technology's capabilities before its rapid adoption.

And that's why the so-called medical arms race matters. With limited resources for health care and a focus on containing health-care spending, every dollar spent in the system truly counts.