Teaching Surgery Without a Patient
Virtual-reality devices at Penn State and other medical centers let residents hone skills
By KATHERINE S. MANGAN
Hershey, Pa.
In a laboratory at a Pennsylvania State University teaching hospital here, surgical residents are racing against the clock, clamping and suturing, grimacing when their tools tear soft tissue.
Today, at least, no lives are at stake. The "operations" they are performing take place in the safety of virtual reality, where the slip of a scalpel won't leave anyone hemorrhaging, although it might earn the resident a low grade.
Penn State's Milton S. Hershey Medical Center is one of a growing number of teaching hospitals equipping their labs with virtual-reality devices that allow medical residents to practice their skills on machines rather than on patients.
Some day, proponents believe, all surgical trainees will be required to practice this way. Sending a surgeon into the operating room without simulated practice will be as unthinkable as allowing a pilot to command an aircraft before putting in hours on a flight simulator.
"Patients are not very accepting of surgical training being done by new trainees for the first time on real, live patients," says W. Bosseau Murray, an associate professor of anesthesia who is research director of the Penn State surgical-simulation lab. "Simulation is both safer and cheaper."
It may be cheaper in the long run, but it requires a hefty investment up-front. The Hershey laboratory, which is operated jointly by the departments of anesthesia, nursing, and surgery, has more than $1-million worth of simulation equipment.
One of the most advanced devices is the Minimally Invasive Surgery Trainer. The MIST system, as it's known, consists of a frame holding two forceps that are electronically linked to a powerful computer. A television screen shows a simulated image of the instruments' position and movement.
Residents manually adjust the forceps to manipulate the image as the computer program guides them through six surgical skills. In one, the resident passes a virtual sphere from one instrument to another. The computer grades the user on each skill, measuring how long it took to complete the task, how many errors were made, and how efficient the movement was. For example, someone who took a large, looping motion to get from one point to another would be penalized. The exercise tests manual dexterity in mimicking the actual movements that a surgeon would make, like using a forceps to grab a vein and transfer it to the other forceps.
The system is designed to train residents in laparoscopy, or minimally invasive surgery, a widely used technique that allows them to perform minor surgery through small incisions. The surgeon inserts a device consisting of a slender tube, a system of lenses, and a tiny video camera through a small hole in the abdominal wall and observes the image on a television screen.
William N. Wang, a laparoscopic-surgery fellow at Hershey, says his sessions on the MIST system when he was a resident here made him more relaxed when it came time to operate on a real patient. "It allowed me to practice handling a needle before entering the operating room, and made me feel more confident," he says.
The simulator approximates the difficulty of performing an actual laparoscopy, says a resident, Robert G. Strange, because in both circumstances "the tip of your instrument is in a three-dimensional space, but you're observing the image on a two-dimensional screen."
Residents also can practice open surgery on a simulator that makes them feel like they're actually cutting into tissue. The touch-feedback, or "haptic," feature is controlled by a desktop computer system called the Phantom. As residents sew two pieces of virtual intestine together on the screen, they feel the punch as the needle penetrates the intestinal wall. The needle, mounted in a thimble on a robotic arm, controls its counterpart on the screen.
Residents can practice life-support techniques on an eerily lifelike simulated patient. The computer-controlled mannequin, with a chest that rises and falls with each "breath," can be programmed to mimic all kinds of dreaded conditions, from a collapsed lung to brain damage. Its thumbs even twitch and then fall still as anesthesia begins to take effect. A slip-up can "kill" the dummy, but it can be revived with the flip of a switch.
"It made a huge difference to me, being able to practice on someone who wasn't going to die for real," says Tyrone Girdharry, a resident in anesthesiology. "If I had had to start out in an actual operating room, I'd be standing around, waiting for someone else to take charge. Here, I'm comfortable doing that."
Using the virtual-reality devices to supplement a resident's training can free up a busy surgeon's schedule by reducing the amount of time spent with a learner in tow. So why aren't all surgeons-in-training making their first cuts on virtual patients?
"The unfortunate reality of virtual reality is that it's vastly underutilized, both here and across the country," says Randy S. Haluck, an assistant professor of surgery at Penn State.
For one thing, the equipment is expensive. Many medical schools are unwilling to spend hundreds of thousands of dollars on a patient simulator that might quickly become outdated, Dr. Haluck says.
Richard M. Satava, a professor of surgery at Yale University's School of Medicine who has traveled around the country promoting virtual-reality simulators, says the $300,000-to-$400,000 price tag often scares people away. "The response is overwhelmingly positive -- until they find out how much they cost."
Besides, many doctors are leery of the technique. They're not convinced that a computerized system, no matter how realistic, can teach residents the skills they will need in a real operating room.
Even those who use virtual-reality devices for training concede that much of the technology isn't advanced enough to replicate a real patient. "For the most part, we're not yet ready for prime time," Dr. Haluck says. But it's only a matter of time, he adds, before virtual reality becomes an essential stage of a surgeon's training.
The traditional model for learning to perform surgery -- by practicing on real patients -- doesn't allow residents to repeat the same skill until they're comfortable with it.
"If you're learning about suturing, I can't make a three-foot-long incision for you to close just so you can practice suturing," says Dr. Haluck. "I can't open it up again to allow you to try it again."
And the pressure of learning on live patients can take its toll on residents, he says. "In the operating room, the stress level is often high, and you're working against the clock. There's no room for repetition or error."
Like Hershey, other medical schools also are developing virtual-reality projects. Researchers at Stanford University are building "virtual patients" that can be programmed to replicate specific conditions.
Say, for example, a grandmother comes in with a complicated hip fracture. Using computerized axial tomography (CAT) scans and other tools, surgeons could gather information, program it into her virtual counterpart, and try out different techniques and tools the night before the operation.
The next morning, the doctors would have a pretty good idea of what obstacles they were likely to face, and how to overcome them.
Looking farther into the future, Stanford researchers hope that eventually, information gleaned from a virtual operation could be programmed into a robot surgeon that would actually perform the operation on the human patient.
Yale's medical school offers its surgical residents a simulation laboratory in which they can work on their hand-eye coordination. For now, it's a decidedly low-tech approach.
In one exercise, a technician measures the residents' timing and accuracy as they pick up beans with a laparoscopic tool and place them in a hole. It's tougher than it sounds; the residents see the beans only on a television screen, on which the image is displayed in reverse. Surgical residents who spend about 25 hours in the lab over a five-day period improve their skills by an average of 30 to 40 percent, says Dr. Satava.
Six months from now, those skills are to be measured by six new simulators, which will allow residents to practice a wide range of procedures, including anesthetizing patients and probing internal organs. A typical report card scores residents on how much they damage the tissue, whether the scalpel was inserted at the proper angle, and how much force was applied, among other measures. Too little force won't cut through the tissue; too much could damage it.
Such sessions will never replace the time a resident spends with a surgeon as mentor, but it could make those sessions more productive, advocates believe.
"Eventually, it will save time and money, but to get there, it takes an enormous investment up front," says Dr. Satava.
But cost shouldn't be the deciding factor; patient safety is more important, Dr. Satava argues.
"We don't ask how much it costs to train pilots on a flight simulator," he says. "Why are we insisting on saving money when it comes to training surgeons? People die on a regular basis because surgeons aren't trained well enough."
That message was hammered home in a report released last November by the National Academy of Sciences' Institute of Medicine, which found that medical errors, some of which happened during surgery, kill at least 44,000 people each year.
As surgical simulators become more advanced and their cost is reduced, more and more teaching hospitals will invest in them, Dr. Satava believes.
"The whole field will change dramatically in the next 10 years," says Christoph Kaufmann, an associate professor of surgery at the Uniformed Services University of the Health Sciences, the nation's only military medical school. "Before long, there will be a virtual-reality simulator in every surgical-training hospital, so that while they're waiting for the patient to go to sleep, they can be practicing the procedure."
Dr. Kaufmann directs the new medical-simulation laboratory in the Bethesda, Md.-based university. The lab opened in January with an extensive collection of virtual-reality devices and simulators, on which residents who are training to become surgeons can practice battle-specific techniques like repairing bullet wounds and picking bone fragments out of a patient's leg.
Using the same virtual-reality trainer, they can also practice sewing together blood vessels or examine the internal structure of a virtual eye.
"We're at the Wright Brothers stage right now," Dr. Kaufmann says. "We have the basic tools we need, but we can't take along a lot of people with us."
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