Software debugging method touted for boosting safety of surgical robots

Researchers from Carnegie Mellon and Johns Hopkins universities are touting a new method of reliably detecting software bugs in surgical robots and for verifying the software is safe. They plan to present their findings Thursday at the Hybrid Systems: Computation and Control conference in Philadelphia.

Surgical robots are an example of a hybrid, or cyber-physical system--complex, computer-controlled devices that are becoming increasingly common, according to an announcement.

"Because the consequences of these systems malfunctioning are so great, finding a way to prove they are free of design errors has been one of the most important and pressing challenges in computer science," André Platzer, assistant professor of computer science at Carnegie Mellon, said. Trial-and-error testing can't check every possible circumstance the system might encounter.

Platzer and associates used differential dynamic logic and a tool called KeYmaeraD that can model a hybrid system, then symbolically pick it apart. Platzer previously used this approach to identify errors in aircraft collision avoidance systems and to verify the safety of distributed car control systems.

This research used robots used in surgery at the base of the skull. With eye orbits, ear canals and major arteries and nerves close together, a surgical tool easily could create damage if it went astray. Surgeons use the robots for intricate movements, and the software sets boundaries for movements that surgeons can't always see.

The researchers, however, found problems, including that the safety feedback for one boundary could interfere with that of the adjoining boundary, allowing the tool to be pushed beyond limits set by the surgeon.

Using this formal verification technique, the researchers developed a new algorithm to prove the software was safe, according to the announcement. The researchers are calling for further development of the system.

The use of surgical robots is increasing, despite the higher cost--especially for hysterectomies. Health officials in Massachusetts recently sent hospitals an "advisory" letter outlining safety concerns regarding robotic surgery, and the American Congress of Obstetricians and Gynecologists stated that robotic surgery for hysterectomies shouldn't be the first--or even second--choice for women undergoing routine procedures.

What's more, last month, the U.S. Food and Drug Administration announced it would take a closer look at the safety record of da Vinci surgical robots.

A study published in the Journal of Urology raised more questions about the safety of robotic surgery. It found that one in 15 people who undergo robot-assisted surgery on the prostate, kidney or bladder develop nerve injury, though usually temporary, related to their positioning on the table, Reuters recently reported.

To learn more:
- find the announcement
- read the Journal of Urology abstract
- here's the Reuters story