Surgical Robots Make the Cut


If you are one of the 450,000 Americans each year who require coronary surgery, take heart. Your surgeon may have a helper that will make the operation safer -- and shave weeks from your recovery time. Who is this skilled assistant? A robot.

"Surgery is meeting the Information Age," observes Ralph J. Damiano Jr., chief of cardiac surgery at Washington University School of Medicine in St. Louis. "Integrating computers into the operating room will have a revolutionary impact, not only on heart surgery, but on many types of procedures," predicts Damiano, who pioneered "computer-assisted" heart surgery on a human patient at the Hershey Medical Center of the Pennsylvania State University College of Medicine in 1998.

X-Ray Vision: An MRI scan is precisely superimposed on the patient. The

surgeon can actually do a dry run on a virtual model

CREDIT: Medical Vision Group, MIT AI Lab

Several "surgibots," especially those developed by two California startups -- Computer Motion of Santa Barbara and Intuitive Surgical in Mountain View -- are being tested on growing numbers of patients (see BW Online, 6/14/01, "Battle of the Robosurgeons"). These Space Age systems promise to permit surgeons to perform increasingly difficult operations by remote control deep in the body. And they do it through tiny incisions that could be covered by a Band-Aid. Surgical robots, which are already being used in coronary-bypass operations, are moving rapidly into other surgical areas, like repairing damaged heart valves and, eventually, the brain.

MEDICAL MILESTONE. Reports on the first clinical tests of computer-assisted heart surgery are giving surgibots a clean bill of health. During 1999, Damiano led the first clinical trials approved by the Food & Drug Administration in which remotely controlled instruments were used to graft arterial bypasses into the ailing hearts of 19 patients at Hershey.

Now, in a follow-up study, published in the June issue of Annals of Surgery, Damiano and his colleagues report that medical imaging revealed all the patients' grafts were open six months after surgery. One year after the procedure, all patients were alive and doing well.

The findings are especially significant because heart surgery has remained one of the most invasive operations performed by doctors. To gain access to the heart, traditional surgery techniques demand a 12-inch to 18-inch incision in the chest so that the the breastbone can be propped open -- one of the main sources of post-operative pain. Surgeons then put the patient on a heart-lung machine to stop the beating heart. All this adds up to a greater risk of death -- and more than a month of uncomfortable recovery.

For operations in other areas of the body, surgeons have found ways to work through very small incisions using long instruments and a television camera to view the operating site. One technique, known as arthroscopy, has been used for joint surgery -- particularly to repair injured knees -- since the 1970s. Other so-called endoscopic procedures are now common in some abdominal surgeries, such as gall-bladder removal.

LOOK, NO HANDS. But the heart defied endoscopic surgery until Damiano and a small number of doctors around the world began experimenting with robosurgery. The reason: patients' ribs below the chest bone limited the freedom of movement necessary to perform the delicate operations. "To date, performing endoscopic coronary-artery surgery by hand has been impossible, beyond the limits of dexterity of any heart surgeon," says Damiano.

While Damiano insists that "heart surgeons have steady hands," these days he is relying on a helper named Zeus-- the Zeus Robotic Surgical System developed by Computer Motion. When Damiano operates, his hands never touch the patient.

Instead a three-armed, $1 million robot is at the operating table. Damiano sits at a computer console in a corner of the operating room. A screen displays the patient's heart from a tiny camera inserted into the patient through a puncture about the size of a pencil. The camera is controlled by simple voice commands -- "Move in. Stop. Back. Right. Left. Stop."

TWO YEARS OF TRIALS. Two other incisions in the patient admit surgical instruments used for grasping tiny blood vessels, then cutting and stitching them back together. Damiano holds and manipulates a duplicate set of tools, and -- as if playing a Nintendo video game with a computer joystick -- their real counterparts inside the patient, precisely replicating every move he makes.

Since the image of the operating site is magnified, when the surgeon moves his virtual scalpel an inch, the real instrument travels only a quarter of that distance. In addition, Zeus's software detects the slightest tremor in the surgeon's hand and filters it out -- an advance that allows the instruments to move with an accuracy that exceeds the usual idea of "surgical precision."

Before Damiano operated on his first patient, he and his colleagues spent spent two years perfecting their techniques on inanimate objects, cadavers, and animals. But with the success of the early bypass operations, he and others are attempting increasingly challenging operations.

"SUPERHUMAN" ABILITIES. The next step in bypass surgery -- one now being explored -- is operating on a beating heart. In the earlier robot operations, patients were connected to a heart-lung machine and their hearts were stopped. In April, a team of surgeons at the University of Pittsburgh Medical Center completed the first beating-heart bypass on a 63-year-old male patient. The operation was part of a new series of clinical tests at 12 medical centers. "We can perform superhuman tasks because the robot overcomes our dexterity-and-precision limitations," says Marco A. Zenati, who operated the Zeus robot system.

Meanwhile, Zeus' arch rival, the da Vinci Surgical System developed by Intuitive Surgical, is honing its skills by repairing leaking heart valves at several medical centers, including Ohio State University and the University of Southern California. Last month, for example, doctors at USC's Keck School of Medicine sent home their first patient after correcting a leaking mitral valve in an FDA clinical test.

The mitral valve separates the upper and lower chambers of the heart. When it leaks, blood can back up into the lungs and force the heart to work harder, causing shortness of breath and tiredness. Working through three small incisions between the ribs, surgeon Vaughn Starnes shortened a ligament that supports the valve and sewed a reinforcing ring into place to brace it. "This is a procedure not many people across the country do, even without a robot," notes Daniel Schwartz, who assisted in the operation.

ONCE AGAIN, WITH FEELING. The heart, however, is just a start -- the next frontier is the brain. A group of researchers headed by Peter D. LeRoux, a neurosurgeon at the University of Pennsylvania Medical Center, is testing a computer-controlled microsurgery system co-developed by NASA's Jet Propulsion Laboratory in Pasadena and MicroDexterity, a startup in Albuquerque, N.M., so that earthbound doctors could operate on astronauts in space.

The Pennsylvania team is testing the system to see how well it works on delicate neurosurgery procedures. So far they have used their surgibot to repair tiny blood vessels in the brains of 10 laboratory rats. Although the operations took longer than average, the investigators say the concept is sound, though they are quick to add that further development is needed.

LeRoux wishes the system would provide tactile feedback because surgeons rely a great deal on the "feel" of a scalpel against tissue. "This technology is just a crude prologue to some of the amazing things that are ahead," he says.

MODEL PATIENTS. Indeed, LeRoux may not have to wait very long. In 1998, the National Science Foundation set up a new research collaboration to develop the operating room of the future. Headquartered at Johns Hopkins University in Baltimore, the Center for Computer-Integrated Surgical Systems and Technology brings together scientists from Johns Hopkins, Massachusetts Institute of Technology, and Carnegie Mellon University -- each teamed with medical groups at affiliated hospitals. Support comes from the NSF, the member institutions, and industry.

While some of today's systems provide rudimentary tactile feedback, better ones are under development. Meanwhile, scientists are rushing to create an entire virtual operating room. Before an operation begins, surgeons will be able to make a diagnosis and practice on a virtual model of the patient's brain or other organ produced from medical scans such as a MRI.

By moving a virtual endoscope, the surgeon can "fly" through the patient. During actual operations the computer images are superimposed on the actual images of the patient. "By using real-time imaging and real-time sensors, we will be able to match the virtual reality of this plan with the actual reality of the surgery," says Russell H. Taylor, who heads the Computer Aided Surgery Lab at Johns Hopkins. With humans to guide them, robots are taking a place on the cutting edge of surgery.

Further Information

Computer Integrated Surgery Lab at Johns Hopkins, go to http://www.cs.jhu.edu/labs/cis/about.html

Center for Medical Robotics and Computer-Assisted Surgery at Carnegie Mellon, go to http://www.mrcas.ri.cmu.edu/

Medical Vision Group at MIT's AI Lab, go to http://www.ai.mit.edu/projects/medical-vision/index.html By Alan Hall in New York


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