This
new form of surgery, Damiano says, represents nothing less than a surgical
earthquake that will send shock waves throughout the entire field over the
coming decade.
Ralph J. Damiano, Jr. MD |
|
IN A RESEARCH LABORATORY at the School of Medicine,
Ralph J. Damiano Jr., MD, professor of cardiac surgery, is in the midst
of a dramatic surgical simulation-- but the scene in no way resembles traditional
heart surgery. Damiano is not wearing the special glasses that magnify his
patient's coronary vessels or the headlight that illuminates his surgical
field. He is not holding any of the tiny scalpels, scissors or clamps that
make microsurgery possible. Most strangely, he is not even standing at the
operating table.
Six feet away, Damiano is seated at a computer console,
staring at a monitor that displays the vessels within an animal heart,
at 10 to 15 times their normal size. He is wearing a headset fitted with
a microphone; his hands grasp joysticks with handles that mimic surgical
tools. And looming over the nearby operating table is a space-age instrument:
a robotic device with three giant arms. One holds an endoscope--a camera
and light that illuminates the heart's interior; the other two hold minute
instruments for stitching, grasping and cutting the coronary vessels.
"AESOP," calls Damiano, and the computer
answers with an affirmative tinkle. "Move in. Stop. Back. Right.
Left. Stop," Damiano commands, as the endoscopic arm of the robot
responds obediently to every new order. "Save position one,"
he adds, and the computer commits a position to memory, ready to return
to it later. "Position one saved," replies a robotic voice.
While Damiano's voice directs the endoscope, his hands
deftly work the controls for the other two robotic arms. In real procedures--any
one of the 20 coronary bypass procedures he did in 1998Ð1999 as part of
a groundbreaking clinical trial, while he was on the faculty at Penn State
University--he has used these arms to perform the surgical work, while
studying the monitor carefully to gauge his progress.
"Robotically assisted surgery" is what most
people call this remarkable new technology but Damiano-- concerned that
people will picture autonomous, 'Star Wars'-style robots--prefers the
term computer-assisted surgery. Either way, he says, this technology effectively
takes a surgical instrument and splits it in half. Between the handle
(which he holds) and the instrument tip (inside the patient) is a computer
using sophisticated software to digitize the surgeon's maneuvers and relay
them in real time to the robot arms. By digitizing the movement, the computer
can be used to perfect each surgical maneuver.
This new form of surgery, Damiano says, represents
nothing less than a surgical earthquake that will send shock waves throughout
the entire field over the coming decade. As robots improve and become
less expensive, more disciplines will adopt these computer-assisted techniques
and find exciting new ways to use them--transforming current procedures
and developing new ones, even on a cellular level.
The School of Medicine will be at the forefront of
this revolution, with a research program in computer-assisted surgery
that will become one of the most active in the United States. Damiano
has just received Food and Drug Administration and when he receives institutional
approval, probably by early November, he will begin a new round of clinical
trials on coronary bypass patients using robotically assisted techniques.
In November, he will teach them to other surgeons in his first course
at the new Washington University Institute of Minimally Invasive Surgery
which opened in late October.
"This is surgery meeting the information age,"
says Damiano, chief of cardiac surgery within the division of cardiothoracic
surgery at the School of Medicine and Barnes-Jewish Hospital. "For
the first time, we are integrating computers into the operating room.
While the information technology revolution has totally changed American
business, it has not had a dramatic impact on the technical performance
of surgery--until now. What we're seeing is the early days of a revolution
that may transform the way surgery is done."
Bypassing conventional surgery
Conventional coronary bypass surgery has several limitations.
To reach the heart, surgeons must make an 18-inch incision or "median
sternotomy," dividing the patient's breastbone; to avoid the problems
of operating on a beating heart, they place the patient on cardiopulmonary
bypass, using the heart-lung machine. These procedures mean some pain
during recovery, a risk of surgical morbidity--and a month or two of recuperation.
To move toward more minimally invasive surgery, cardiac surgeons have
recently tried two strategies: decreasing the size of the incision and
operating "off-pump," on the beating heart. But a large scar--and
the attendant recovery problems--still remain. So nearly four years ago,
Damiano and several colleagues around the world began looking at ways
to perform bypass surgery endoscopically, though a series of small "ports"
in the chest, none wider than the diameter of a pencil.
To do that, they would need long instruments, some
12 to 18 inches in length--a far cry from the usual 4- to 5-inch instruments,
so easily cradled in the hand. These long instruments, they found, augment
even the faintest tremor. Since coronary arteries are the size of strands
of spaghetti, eliminating any extra motion is extraordinarily important.
"Heart surgeons all have steady hands, but it's
impossible to hold these long instruments steady when you are working
on really small vessels," says Damiano. "To date, performing
endoscopic coronary artery surgery by hand has been totally impossible--beyond
the limits of dexterity of any heart surgeon in the world."
But a robotic arm, assisted by computer technology,
does not face these same limitations. In fact, a computer can filter out
high-frequency motion from the electronic signal, thus removing all traces
of tremor--and increasing the surgeon's dexterity. At the same time, it
also can scale the surgeon's motions, so that Damiano and others can perform
microscopic motions at high magnification--but still perceive them as
gross, easy-to-perform movements.
"While surgical loupes typically give us from
2.5x to 3x magnification, this robotic endoscope/camera gives us 10x to
20x magnification, which enhances our visualization of anatomical detail.
We also can get that visualization right down into the surgical field,"
says Damiano. "And the camera is being held by a robotic arm that
never gets tired and is under direct voice control."
The robotic system that Damiano has been helping to
test and develop is the ZEUS Robotic Surgical System, made by Computer
Motion, Inc., of Santa Barbara CA. Another model is the Da Vinci telemanipulation
system, made by Intuitive Surgical, Mountain View CA, and now in use at
several European centers.
Damiano and his colleagues at Penn State were among
the first in the world to begin actively working with this technology.
For two years, they honed their techniques on inanimate objects, then
moved to cadaver models and animal studies. Finally, they received FDA
approval for a trial on 10 patients, the first in North America to undergo
endoscopic bypass grafting. The results were so successful that they received
approval to perform 10 more; this time, two other centers joined them,
with an additional 13 patients.
"In our series, we had no complications related
to using the robotic system. Also, postoperative angiograms showed that
all the grafts were open at two months without any significant stenosis,
so we were very happy with the results," says Damiano.
Surgical hyper-evolution
Still, FDA restrictions in those trials prevented
Damiano from using fully endoscopic procedures with any of his patients.
He could use computer-assisted technology to do bypass surgery on a single
vessel, the left anterior descending coronary artery (LAD). But most needed
bypass grafts on other arteries as well, so Damiano had to operate on
them using standard open-heart techniques, including a median sternotomy
and cardiopulmonary bypass.
During this next clinical trial at the School of Medicine
and Barnes-Jewish Hospital, which will also include eight to 10 other
major U.S. centers, Damiano expects that the FDA will still impose strict
guidelines. But as each trial offers new evidence of the technology's
safety and efficacy, he says, the patient base will broaden. In Canada
and Europe, where regulations are less strict, medical centers have already
begun doing bypass on more than one coronary vessel with excellent results.
Damiano is enthusiastic about the future prospects
for this technology. For patients, it may mean a faster recovery, less
pain--and three small scabs on the chest rather than a long incision.
For surgeons, sitting at a console means less physical exhaustion, while
eliminating high-frequency motion may mean a longer active surgical career.
And a surgical expert in a different medical center --even another country--
could easily assist in a procedure through satellite or fiberoptic links.
The School of Medicine plans to become a major player in this kind of
"tele-mentoring," Damiano says.
Right now, computer-assisted technology is still evolving,
as companies work to incorporate three- dimensional visualization and
even the sense of touch, so important to many surgeons. Doctors must learn
to access vessels other than the LAD and even explore applications in
heart valve surgery. The price of this equipment must also come down to
make this technology affordable and cost-effective.
But endoscopic procedures still have the potential
to transform cardiac surgery, just as they have already revolutionized
gallbladder removal, some urological procedures and many orthopaedic excisions,
through arthroscopic techniques. According to "Moore's Law,"
says Damiano, "computer processing power doubles every 18 months."
If a computer is interposed between a patient and surgeon, he adds, the
surgeon's technical ability also may increase exponentially as well.
"I call this a 'surgical hyper-evolution,'"
he says. "We'll do an operation, then suddenly our technical ability
will dramatically improve and that operation will become obsolete as we
discover better, less invasive ways to do the same procedure. As a surgeon,
I find that tremendously exciting because we will no longer be shackled
by our physical limitations. Soon our surgical horizons may only be limited
by our imaginations."
|