Beating Heart Surgery
BY JIM WILSON
POPULAR MECHANICS , APRIL 2000, page 50
Elsie Leffler lookswarily at the video monitor over my head as I tie a neat square knot in a wisp of thread magnified to the size of a rope. "Do you want to try it?" I ask, rising from the control panel. "No," she says as emphatically as though Id offered to close her hand in a car door. Its an understandable reaction. Not long ago Leffier, who looks too young and healthy to have ever set foot in a hospital, was on the other side of this machine. She was the first patient to undergo a robotically assisted "cabbage," surgeon-speak for an endoscopic coronary artery bypass graphing procedure. In several years, when the Zeus Robotic Microsurgical System that POPULAR MECHANICS has been invited to "test drive" becomes commonplace; this pioneering procedure may become the most common heart operation performed.
Robots have been .in the operating room for nearly a decade, helping surgeons guide probes into the brain and aiming lasers that correct vision. For even longer, doctors have used endoscopic instruments; essentially tiny cameras and surgical tools attached to long sticks. So-called Band-Aid surgery is now the standard way of repairing most knee injuries, performing appendectomies, and, most recently, removing organs from living donors.
In theory, the same tools and techniques could be used to perform heart surgery, thereby eliminating the necessity of "cracking the chest" to reach the heart. And, for several years in the late 1990s, some surgeons used a modified "cabbage" procedure. In practice this operation proved so difficult that many of these surgeons went back to, the more direct approach, despite its longer and more painful recovery period. "The length and imprecision of standard endoscopic instruments contributed to this failure," says Dr. Christopher T. Ducko, chief of cardiothoracic and vascular surgery at the Milton S. Hershey Medical Center, in Hershey, Pa., where Lefflers operation took place.
The surgical robot that assisted in her operation promises to solve this shortcoming by merging motion control technology developed for brain and eye surgery with commonly used endoscopic tools. "Basically the idea is to put modern software between your hand and the instrument," says Dr. Edward R. Stephenson Jr., Duckos colleague.
"The surgeon manipulates traditional surgical instrument handles," explains Ducko.
"His movements are relayed in real time by a computer to robotic arms which are attached to the operating room table." The system removes the tremor and motion exaggeration inherent in the use of endoscopic instruments, challenges familiar to those who have used telescoping pruning saws. Eventually the software will be able to move the instruments back and forth in time with the heart. The goal is to "bypass" a blockage in a critical heart artery, all without cracking the patients chest or putting him or her on a heart-lung machine. When this happens; one-day hospitalizations following surgery on beating hearts could become the norm.
Before sitting down at the controls of the Zeus robot console, I spend part of the morning a few doors away, in the Penn State University College of Medicine Simulation Development and Cognitive Science Laboratory. In this "virtual hospital" I try my hand at a series of warm-up exercises. I begin by grabbing hold of what looks like a pair of draftsmans dividers, hinged point-to-point. Holding them like a pair of tweezers I feel a springy pressure against my thumb and forefinger. On the video monitor, I can see an angry pair of clippers open and close. My first exercise seems simple enough. Maneuver a computerized ball inside a computerized box. At least it seems simple until I move the tip of the instrument out of bounds. Steel is sharp and tissue is soft. The screen turns red, telling me Ive just violated the first rule of medicine: Do no harm. After a few more computerized casualties, I get a new appreciation of the term "practicing medicine."
"Its a different set of skills from operating with forceps and scissors," says Dr. Randy S. Haluck, director of minimally invasive surgery at Penn State. My own surgical skills being limited to removing splinters with the tweezers in my Swiss army knife, Ill take his word for it.
I graduate to the next training station, where I get to use both hands. Here the objective is also simple: Place cylinders, about the diameter of fat pencil leads, into holes in a pegboard. Any kindergarten kid could do this blindfolded, while eating a peanut butter sandwich. But the technology that makes minimally invasive surgery possible adds a few complications. The only way I can see the cylinders or the pegboard is on a video monitor. And then, only if I properly aim a tiny TV camera with my left hand. The lack of touch makes things a bit more difficult, but I pass the test.
After demonstrating my dexterity; and feeling rather proud of it, I have a humbling encounter with my first patient. He cant breathe. My task is to open an airway by placing a tube down my patients throat and connecting it to an oxygen supply. Or, as fans of medical shows might say, to "tube him." Dr. W. Bosseau Murray lifts my patient from behind the neck and shines a light down his wide-open mouth. "See that inverted V?" he asks. I nod. "Vocal cords. Be careful." After pointing out a few other anatomical landmarks, he leaves me on my own. My glance down my patients throat has given me a minds eye view of the tube as it moves into position. Confident Im on target, I turn on the air supply, and blow out my patients lung. "See why you dont want to do this in the emergency room for the first time?" asks Murray.
Although robot surgeons do the glamour work, the quarter-million-dollar robo-patient that has just perished on my watch will play a major part in training future doctors. Reboot the computer and hes ready for me to have another crack at saving his life, this time by injecting an antidote. My plastic patient is wired to the same sort of vital-sign monitoring gear found in intensive care units. "The instruments dont know it isnt human," Murray says before initiating the next disaster, an adverse drug reaction.
In the next 15 seconds I select from 50 different medications. Then, based on my judgment of the patients condition and body weight, I administer a dose. After I get the real needle the right distance into the artificial skin, without damaging the plastic vein, the dummy measures the volume of liquid Ive injected. A bar code identifies the drug and the computer decides whether robo-patient lives or dies. The warning tone and flat line on the monitor tell me my patient is a goner. "Every anesthesia resident spends three days here before he can go near a patient," says Murray.
There has always been a certain amount of resistance to adopting new medical tools. So some hesitation in the wider medical community is not surprising. "Even simple tasks like placement of a bulldog clamp are sometimes not easily achieved with current telemanipulation systems," cautions Dr. Volkmar Falk. A cardiac surgeon at the University of Leipzig, in Germany, he has looked closely at the Hershey experiments. His chief criticism is that the current robotic arms have limited mobility, compared to a surgeons hand. The Hershey surgeons predict technology will continue to improve with each generation of equipment. They also believe that no matter how smart robots might become they will never be promoted beyond the level of assistants. "Every artery is different," says Stephenson. "There is still a fair amount of art in this work."