inserting a needle for a cancer biopsy or burning into the brain to remove a tumor.

“It is like a car where the lane-following is autonomous but you still control the gas and the brake,” said Greg Fischer, one of the Worcester researchers.

Many obstacles lie ahead, scientists note. Moving plastic pegs is one thing; cutting, moving and suturing flesh is another. “What happens when the camera angle changes?” said Ann Majewicz Fey, an associate professor at the University of Texas, Austin. “What happens when smoke gets in the way?”

For the foreseeable future, automation will be something that works alongside surgeons rather than replaces them. But even that could have profound effects, Dr. Fer said. For instance, doctors could perform surgery across distances far greater than the width of the operating room — from miles or more away, perhaps, helping wounded soldiers on distant battlefields.

The signal lag is too great to make that possible currently. But if a robot could handle at least some of the tasks on its own, long-distance surgery could become viable, Dr. Fer said: “You could send a high-level plan and then the robot could carry it out.”

The same technology would be essential to remote surgery across even longer distances. “When we start operating on people on the moon,” he said, “surgeons will need entirely new tools.”

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