Shrinking the Surgeon

In the operating room of the future, physicians will use tiny high-tech tools to travel inside the body with dexterity and precision beyond imagining.

By Gurney Williams|Saturday, April 01, 2000

Heart surgeon Ralph Damiano's hands move with practiced precision as he prepares to open the chest of 62-year-old David Jones for a double-bypass operation. Damiano makes a 12-inch incision between Jones's neck and abdomen with a scalpel, then cuts through Jones's sternum with an electric saw and cracks the bone apart to expose the diseased heart. To create a clear field for his surgical maneuvers, he inserts a drainage tube into the right atrium and diverts theflow of blood to a heart-lung machine the size of a truck engine. "OK, we're going all the way," Damiano says. He injects a mixture of blood and potassium--which alters the flow of electrochemical impulses--into the heart, causing it to stop. An amplified pulse monitor, sounding steady beats, goes silent, and the operating room is quiet except for the whirring sounds of the heart-lung pump motors. On the video screens, multicolored lines measuring electrocardiograph activity are flat. Jones's burly chest is still.

Time is now of the essence. The longer Jones remains attached to the heart-lung machine, the greater the risk of postsurgical complications like strokes. Damiano deftly sews a piece of healthy artery harvested from Jones’s left arm above and below one blockage, completing the first bypass.

Then he does something completely out of the ordinary for a heart surgeon: He unhooks the power to his forehead light, takes off his magnifying glasses, leaves behind dozens of scalpels, scissors, and clamps, and walks away from his patient.

A few moments later, he settles into an office chair in front of a squat black-and-gray computer console positioned five feet from the operating table and dons an unsterilized headset equipped with a microphone. “Left,” says Damiano.

So goes an endoscope—a camera attached to a robotic arm and inserted in Jones’s body before the operation—scanning to the left, illuminating for Damiano a brightly lit landscape of pink, glistening flesh magnified 10 to 12 times on the computer monitor. As he watches the screen, Damiano then grasps the silvery ends of elbowed computer joysticks, which allow him to maneuver two additional robotic arms that hover over the operating table like brooding black cranes. As Damiano manipulates the joysticks like a master puppeteer, a pair of surgical graspers and the needle driver he will use to help sew the second bypass graft loom into view on his monitor.

This is no fantasy; this is real. It is the operating room of the future.

Damiano, the chief of cardiothoracic surgery at Hershey Medical Center at Penn State University, is one of a handful of doctors using computer assistance and robotic tools in an attempt to revolutionize heart surgery. “For the first time in history we’re interposing a computer between the surgeon and the patient,” says Damiano, 45, a tall man with thick eyebrows, a mustache, a ready smile, and thoroughgoing optimism. He believes these robotic tools will set a new standard in minimally invasive surgery—and eliminate a good deal of the terrible physical trauma associated with opening the heart. If the technology fulfills its promise, there will be no need to cut the sternum and no need to stop the heart. Patients may leave the hospital sooner, wearing three Band-Aids instead of a long line of heavy metal staples.

For now, because the Food and Drug Administration considers computer-assisted bypass operations experimental, doctors in the United States are also required to open the patient’s chest and hook him up to a heart-lung machine so that the surgery can be completed by hand if something goes wrong. But last September, Canadian surgeon Douglas Boyd provided a glimpse of the future of computer-assisted surgery when he inserted tiny robotic tools through four keyhole-sized ports in a patient’s chest and successfully performed the first closed-chest, beating-heart bypass operation without the aid of a heart-lung machine.

Boyd and Damiano both use a computer-driven robotics system called Zeus, which was developed and manufactured by Computer Motion in Santa Barbara, California. The computer hardware that drives Zeus is modest. “It requires about the same horsepower as a high-performance home desktop,” says Computer Motion founder Yulun Wang. And yet commands travel from the console to each robotic joint at a rate of up to 400 times per second. The power of Zeus lies in its software—the 200,000 lines of computer code that harness the machine’s processors to pick up the hand movements of the surgeon as he handles the computer joysticks.

Instantly, the circuits sense and filter out tremors, the nemesis of every microsurgeon. “The system smoothes out my hand motions in much the same way you can filter an image in digital photography and make it perfect,” says Damiano. And a brilliant surgeon who develops a hand tremor might not have to quit operating.

The system is also capable of scaling hand movements down to whatever size the surgeon chooses. “If I tell you to move a foot,” says Damiano, “it’s easy. But try to move one sixteenth of an inch, and you’d have to spend time moving carefully to get it right. It’s much easier to move things in gross distance than to work on a microscopic scale. On the console, I can make very big motions, and the computer will scale it down. There could be a day when you could operate on individual cells.”

The potential benefits of the technology provided by Zeus and similar systems may be extraordinary, but learning how to use them is a challenge. Surgeons accustomed to saving lives with conventional instruments are bound to feel awkward when they start to manipulate these tools. “It’s like the first time you shot a basketball or threw a football,” says Robert E. Michler, chair of cardiothoracic surgery and transplantation at Ohio State University. He recently started using a tiny wrist at the working end of a robotic arm in a system called da Vinci, made by Intuitive Surgical of Mountain View, California.

After practice operations on 25 cadavers, Michler was pleased to discover some unexpected advantages: “I’m right-handed, but with the system I use my left hand a lot more. It’s as if you become ambidextrous. If the situation dictates the use of my left hand to place a suture in a certain position, it’s much easier to do that with the robot than using a freehand instrument.”

Michler’s equipment also offers a three-dimensional view of the magnified operating field. That means that even the two-millimeter distance between the top and bottom of a severed artery registers as nearer or farther away. “Phenomenal,” he says. “It makes everything seem so much larger—or us so much smaller.”


DELICATE MANEUVERS

Ralph Damiano’s operating room setup looks complicated, but in fact there is a clear chain of command that allows the surgeon to make the tiny robotic tools inside the chest do his bidding.

Cables transmit data in two directions. They carry information from the computer to the robotic tools inside the patient’s chest. They also bring information back from the endoscope and the tools to the surgeon, which he sees displayed on the monitor.

The left-hand joystick controls the grasper tool.

The grasper tool stabilizes the artery while the surgeon stitches the graft.

The endoscope is a camera with a light that illuminates the surgical field inside the chest.

The needle driver holds the needle to which a suture line is attached so that the surgeon can stitch the graft.

The computer uses just 64 megabytes of RAM to run the software that lets the surgeon maneuver the endoscope and tools inserted into three small incisions in the patient’sbody. On the large monitor on top, the surgeon sees an image from the surgical field inside the body. The small screen below is a touch screen the surgeon uses to make choices from the software program.

The joysticks are fitted with handles designed to mimic the shape of conventional tools. The right-hand joystick controls the needle driver.

The surgeon wears a headset with a microphone that controls the endoscope. Since he moves the endoscope by speaking, his voice functions as a third arm for him.


As skills improve, a touch of Alice in Wonderland remains. Damiano says it’s like swimming in virtual reality. “You’re still making the motions of swimming, but you don’t feel the water all over you,” he says. “And you can swim across the English Channel and never get tired, or shrink yourself down if you want, and enter tiny passages.”

The view of  David Jones’s heart projected on the Zeus monitor as Damiano begins to make the second bypass graft is so sharp he can see slight bruising at the edges of the incision. While Damiano takes control of the joysticks, assisting surgeon Jennifer Lawton remains at the operating table, where she tugs a section of healthy mammary artery from Jones’s chest wall into position so that Damiano can graft it around the blockage in the diseased artery.

The open end of the freshly cut healthy artery quivers on Damiano’s screen. “You’re doing a lot of shaking, Jennifer,” he says. Lawton steadies her hand by resting it against a solid object; then, with robotic help, Damiano plunges the needle through the outside wall of the artery, grasps its point as it emerges on the other side, and pulls the needle through. Within minutes, he has repeated this needlework several more times, sewing halfway around the perimeter of the artery. The suture line zigzags between the edges of the artery openings like loose thread between a button and a shirt before the tailor tightens up the line.

Next, Damiano picks up a second curved needle, attached to the other end of the suture line, and starts to sew more stitches to complete the graft. Something looks wrong to Damiano: “Jennifer, if you could just gently hold that stitch.” Abruptly, the line snaps. “Uh-oh. Too late. Take that needle away.”

The loss of the needle means Damiano will have to finish the work with the first needle alone, making sure the loose suture line isn’t pulled back through a stitch hole. Despite the glitch, he completes five more stitches in the next four minutes. Then he pulls the suture line taut. The opening of the healthy mammary artery finally meets the opening he has cut below the blockage in the diseased artery, the graft is made, and Damiano uses the robotic jaws to tie off the line with six square knots.


THE BEAT GOES ON

After John Penner, 61, suffered a heart attack two years ago, he found it almost impossible to keep up his dairy farm in Seaforth, Ontario. Just walking the 300 feet from his house to the barn left him with “terrible chest pains,” he says, relieved only by parking himself, breathless, on a bench near his 50 cows. An angiogram showed that one coronary artery was more than 90 percent blocked and he needed a bypass.

Last September cardiac surgeon Douglas Boyd at the London Health Sciences Center in Ontario decided Penner was a good candidate for an operation that would take the history of minimally invasive surgery one critical step further. Although a few surgeons have performed closed-chest bypasses using a heart-lung machine, and others have performed open-heart surgery without a heart-lung machine, Boyd was the first to put the whole package together, using the Zeus system. With its computer assistance as well as its robotic endoscope and tools, he would attempt the first closed-chest, beating-heart surgery.

Research by Boyd and a colleague, cardiac anesthesiologist John Murkin, had indicated that 3 percent of patients suffer strokes after being hooked up to the heart-lung machine. Thirty percent show significant loss of higher neurocognitive functions—for example, the ability to make complex math calculations—immediately after the operation. Six months postop, 20 percent still experience small but worrisome lapses, such as struggling with a crossword puzzle or forgetting familiar names.

Boyd reduced—but did not stop—the movement of a small area of Penner’s heart, about a centimeter square,  with a stabilizer, a horseshoe-shaped brace inserted through a fourth small incision. The stabilizer pressed down on the heart surface to surround and isolate the area, slowing its motion mechanically. Boyd then cut a slot in the blocked artery and inserted a shunt, much like a little straw, through which the blood continued to flow while he grafted the healthy artery right onto the same slot that he had made to insert the shunt. Just before the last two stitches were sewn, he pulled the shunt out of the artery by means of a little string attached to it. “This is not easy to do,” says Boyd, “You’re totally reliant on a video image, the heart is moving, and you’re working with a bleeding vessel that you have to keep clean in a confined space.” But he believes the result is well worth the degree of difficulty and that, as the procedure is developed, it will become easier.

After six hours on the operating table, Penner became the first patient ever to undergo a closed-chest robotic coronary bypass on a beating heart. No heart-lung machine. No cracked chest: His incisions were sealed with butterfly bandages. And today, no more chest pain. Three weeks later, he was out plowing a 10-acre field. A month after the operation, he went ice-skating for the first time in a decade. —Gurney Williams III


A critical test remains. Once Jones is disconnected from the heart-lung machine, Damiano holds a pencil-sized ultrasonic probe against the wall of the artery he has stitched. The probe works like a police radar gun, transmitting pulses of high-frequency sound into the artery and gauging the flow of blood from the return signal. A flow reading above 10 milliliters of blood per minute through the bypass—about two thirds of a tablespoon of blood every minute—will signal that the procedure has worked. A reading of less than 10 means Damiano will have to hook Jones up to the heart-lung machine again and start over.

“Look at that trace!” he says. The readout is 52. Blood is running at the rate of more than three tablespoons a minute.

In theory, the digital connection between surgeon and patient might someday extend well beyond five feet, a possibility that intrigues the Pentagon. Since 1993, the U.S. military has spent $3 million to design a battlefield surgical system stocked with robotic arms and cameras and housed in an armored vehicle. Surgeons stationed safely behind front lines would manipulate tools to stitch up the most serious wounds so soldiers could arrive alive at a nearby hospital.

But researchers developing remote techniques at the Uniformed Services University of the Health Sciences in Bethesda, Maryland, say it will be at least 10 years before tests on cadavers and dummies pay off with ready-for-combat equipment. One challenge will be to figure out how to transmit the flood of 3-D video signals from the field—about 45 megabits of data per second, roughly the equivalent of three Zip disks a minute—especially when generals need bandwidth to communicate during battle. Furthermore, a doctor in Chicago using robotic servants to sew up an astronaut on the moon may be limited by the speed of light, which lags the movements of the surgeon’s hands over long distances. If it takes more than five thousandths of a second for the signal to travel to a robot, “it begins to feel like you’re working in molasses,” says Joel Jensen, a program manager at sri International, a nonprofit institute that has done groundbreaking work in remote surgery. Jensen estimates the maximum distance between the surgeon and the patient should be less than 3,000 miles.

Damiano says that, even if these problems can be solved, it’s still doubtful that surgeons will use remote systems over long distances unless a second surgeon is on the scene, ready to handle an emergency. “It would be relatively unethical,” he says. “You need to be next to your patient. This is an enabling device for surgery that doesn’t replace the surgeon in any way. If a clamp came off an artery, for example, you’d have only about 10 minutes maximum to stop the flow” while trying to find your way on-screen through a rising pool of blood. Much more likely, he says, is using the system to share expertise by satellite or fiber-optic transmission. “Suppose I was doing a certain type of heart-valve surgery for the first time, and I wanted to get the premier valve surgeon in the world—who’s in Paris—to help,” Damiano says. “He wouldn’t have to fly here.”

Damiano also imagines telementoring other surgeons in distant operating rooms himself, without leaving his own hospital. “I could use a Telestrator, like they have on Monday Night Football, and say, ‘Put your stitch here.’ ” Damiano says. “Or I could assist a surgeon right from my desktop in Pennsylvania by manipulating robotic arms.”

Although the potential of robotic tools is just beginning to be explored, progress may come quickly. Laparoscopic gallbladder surgery was introduced in 1987, but it became standard within five years. Yulun Wang of Computer Motion believes this is only the beginning of a profound transformation in the way surgery is done. “Remember Dr. Bones in Star Trek? He picks up this black box and waves it over your body, and you’re fixed. How’s that going to happen? One day a surgeon may use robotic devices to enter the body through its own orifices. They could carry metal instruments inside the body, where they would be manipulated by magnetic levitation. I think surgery’s headed that way. From minimally invasive today to not even a scratch.”

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