VU Inside: Giving surgical robots a human touch

A critical goal in modern surgery is to make procedures as safe and minimally invasive as possible, which often means using robotic tools. Vanderbilt University bioengineer Nabil Simaan says a negative side effect of doing surgery with tiny entry points into the body is that the surgeon loses his or her sense of touch and pressure as well as having a very limited field of view. To address this problem, he is taking robotic surgical tools to the next level by making them incredibly flexible and situationally aware.

“Historically a surgeon would open up the patient and he or she would have the best tools possible–human hands,” said Simaan, associate professor of mechanical engineering and otolaryngology.

Simaan and his team are creating a flexible robot that can maneuver into hard to reach places and give a sense of touch similar to a human hand.

“What’s special about my snake-like robots is that they’re able to sense the environment,” said Simaan. “They’re able to sense a contact and they’re able to estimate where the contact is so they can readjust on their own, without the surgeon having to do it.”

For example, if the surgeon is manipulating the gripper, which controls the tool inside the patient’s body, and part of the mechanism hits a part of the body it shouldn’t, the flexible robot can figure out a way to reposition itself while keeping the surgical tool in place.

This not only prevents injury, it allows the surgeon to focus on the task at hand.

How is this unique?

Simaan says his snake-like robots are unique because other devices that exist right now on the market are essentially motion replicators.

“If I move my hand this way, the robot moves its hand similarly on the other side inside the patient,” said Simaan. “What we’re trying to do is go beyond the manipulation assistance into a process where the robot itself is helping the surgeon understand what the task is and is helping achieve the task.”

Simaan says by having the robot partner with the surgeon, it helps elevate the surgeon’s skills and ultimately the quality of the surgery.

The snake-like arms can move in all the directions a surgeon’s hand can move, with a “wrist” that rolls. They can also move in a very confined space and can perform dual arm tasks like knot-tying.

“It’s actually better to leave some of the task, for example of regulating the force on the tissue, to the robot controller than having the human worry about it,” said Simaan. “The surgeon is still controlling that level, but they don’t have to worry about actively controlling it every fraction of a second.”

Vocal cord surgery

Simaan and other Vanderbilt researchers are experimenting with these robots in multiple procedures. One is vocal cord surgery—very common among singers.

Currently, singers who undergo vocal nodule surgery have to undergo full anesthesia in an operating room.

studio portrait

Nabil Simaan (Vanderbilt University)

“To gain access from the mouth into the airway you would have to pull basically the neck of the patient as straight as possible. You have to insert a tube through the mouth that generally butts against the teeth and helps keep the jaw open, then push the tongue out of the way,” said Simaan.

The current procedure can sometimes cause injury. Simaan says his flexible robot would go through the nose, bypassing a gag reflex in the throat, turning a major surgery with full anesthesia into a more simplified out-patient procedure.

“We can actually take something that’s now expensive in the way we’re doing surgery and we can maybe, with the help of new technology, simplify it, reduce trauma to the patient, and at the same time reduce health care costs,” said Simaan.

From cars to surgical robots

Simaan’s road to biomedical engineering started in an auto shop.

“I was supposed to be a car mechanic initially,” he said. He started in vocational school working on cars, then taught himself math and physics to earn his way into college, graduate school and now his own successful lab. “It’s amazing. It allowed me to come to the U.S., meet my wife and start my family here. It’s also allowed me to really be one of those lucky few who is happy and excited about coming to work.”

Future of medicine

Simaan says guiding graduate students is an aspect of is work that he finds most fulfilling.

“One of the wonderful things that I do is being able to see students go out of this lab and really impact industry and academia,” said Simaan. “If we look at what students actually achieve when they have an experience here is they learn how to build these incredibly intricate mechanical and electro-mechanical devices. They learn the mechanical design aspect, the electronics aspect, the control aspect and the programming to a point where they can actually build their own robot for research purposes.”

Simaan says they can join industry with much more knowledge and experience than they’d have without the advanced degree.

“Surgical robotics has always been one of those areas on the forefront of robotics,” said Simaan. “My graduate students and I are working here in a wonderful integration environment–computer science, mechanical engineering, all of these different engineering disciplines and science disciplines have to come together to solve a problem in a way that is helping improve people’s lives.”

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