The Next Generation of Surgical Robots

Smaller, lighter, and less expensive

7 December 2012

Surgery can be anything but stress free. Beyond the anxiety over the procedure’s outcome, patients must often deal with complications, long recovery periods, and large, painful scars. Minimally invasive surgeries, which have become increasingly common, alleviate many problems. With their smaller incisions, they tend to result in faster healing and fewer post-op woes.

In a typical laparoscopy procedure, for example, a surgeon makes small cuts in the patient’s skin through which small operating tools and a camera are inserted. The surgeon then views the operating site, usually on a monitor, while controlling the tools. But minimally invasive surgeries, used for such procedures as removing an ovarian cyst or a prostate gland, have their challenges. The rigid instruments used are typically more than 30 centimeters long—which can exaggerate a surgeon’s normal hand tremor.

In addition, surgeons must deal with what’s known as the fulcrum effect: When the hand moves to the right, the tip of the surgical instrument moves to the left. And because such surgery requires extensive operating skills and dexterity, surgeons face a difficult learning curve.

Enter robots, which have made their way into operating rooms to alleviate some of those drawbacks. Among the most popular is the da Vinci surgical system [pictured above], introduced in 1999 by Intuitive Surgical of Sunnyvale, Calif. Unlike a traditional surgeon, a doctor using the robot does not handle most of the surgical instruments directly. Instead, after making the small incisions, the surgeon inserts instruments attached to three or four robotic arms, one of which holds a stereoscopic camera.

The surgeon then sits at a control console near the operating table, looks through a viewfinder to examine 3-D images from inside the patient, and uses joystick-like controls located beneath the screen to manipulate the surgical tools. The da Vinci, with more than 2400 systems installed at nearly 2000 hospitals worldwide, is now used in about 80 percent of prostatectomies in the United States.

But such surgical robots also have their problems, not the least of which is their expense. At more than US $1 million, a da Vinci system is a steep investment for a hospital. Plus, the robot’s size and weight—about 180 centimeters tall and more than 900 kilograms—can be an issue. And if a complication arises and the operation must be converted to an open surgery, it’s difficult to move the robot out of the way quickly so the surgeon can step in.

IEEE Fellow Guang-Zhong Yang and other engineers are hard at work developing a new generation of robots that can give surgeons a wider variety of options. Yang is director and cofounder of the Hamlyn Centre for Robotic Surgery and deputy chairman of the Institute of Global Health Innovation, both at Imperial College London. He was also a speaker at the IEEE Life Sciences Grand Challenges Conference, held in October in Washington, D.C.

“My vision is that future surgical robots shouldn’t be large and expensive machines that are accessible only to the privileged few,” Yang says. “Robots should be a lot smaller, more affordable, and integrated more seamlessly with normal surgical work flow.”

Yang and his colleagues, with a bit of reptilian inspiration, have built such a robot.

SURGICAL SNAKEMany surgeries, including those performed on the heart, throat, and stomach, involve getting to tissue deep within the body. That can be a challenge for a minimally invasive approach because the instruments are long and rigid. But Yang and his team—which includes computer scientists, physicists, and surgeons—developed a snakelike robot that can help surgeons do the job.

The i-Snake (which stands for imaging-sensing-navigated, kinematically enhanced) robot has fully articulated joints, allowing the tool to move around obstacles just as a snake can. The joints are powered by micromotors, and the tip is fitted with multiple sensing and imaging mechanisms.

The i-Snake’s flexibility yields perhaps its biggest benefit: Surgeons can guide the tool into regions of the body that are hard to get at, with minimal cutting. “If you can navigate between natural anatomical planes, you don’t have to cut through muscles or cause inadvertent damage to structures such as the nerves—which makes recovery much better,” Yang says.

The robot requires just one incision, as opposed to the several used in today’s laparoscopies for inserting an endoscope and surgical tools. Using a joystick, the surgeon can digitally control the robot’s shape and movement inside the body.

“The i-Snake is not meant to compete with or replace the da Vinci robot, per se,” Yang says. “It is based on a different principle. We wanted to develop something that is more hands-on, as a smart instrument, rather than large machinery—similar to how computers are now (such as mobile devices) compared to what they were like more than 20 years ago.”

The i-Snake is about 12.5 millimeters in diameter and can have a variable length, typically about 40 centimeters long. It can be held by the surgeon or have its end docked on to a robotic arm fixed to the operating table. The robot has a hollow center through which surgeons insert different surgical tools.

“The i-Snake can increase surgeons’ perception and the consistency of their motor manipulation skills, ultimately improving the outcome of the surgical procedure,” Yang says.

Last year, a paper on the i-Snake won the Best Medical Robotics Paper Award at the IEEE International Conference on Robotics and Automation.

So far, the team has tested the i-Snake on animal subjects. Yang says he hopes to see the device in hospitals within five years. “I think we are close to that,” he says, adding that the robot could be used to perform gastrointestinal, gynecological, and cardiothoracic surgeries.

CHEAPER OPTIONSThe key to making surgical robots less expensive lies in their size, according to Yang. “When I design a robot,” he says, “my thinking is that if you cannot carry it in a case, then don’t bother making it. You want it to be compact and small.”

Another way to keep the price down is to make robots geared to specific tasks. “You don’t want to try to make a robot that can do everything,” Yang says.

Yang envisions that surgeons will one day have a fleet of small robots at their disposal, each to help with different tasks. “In the future,” he says, “you may have four or five robots in the operating room. One may be for dissecting delicate tissue, another for precision-controlled tissue ablation, and yet another for microscopic anastomosis.

“Robots are ultimately just very smart instruments. They can be used to enhance a surgeon’s vision, dexterity, or precision—all with less pain and trauma for the patient.”

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