The da Vinci Mode
Robotic Tools Offer Surgeons a Steady Hand and a 3-D View of the Future of Medicine
By Julian Orenstein
April 27, 2004
Paul Massimiano's specialty is fixing damaged mitral valves -- the flaps of tissue that help maintain the proper flow of blood through the heart. While performing the most delicate part of the repair procedure on a January morning at Inova Fairfax Hospital, however, Massimiano planned to be several feet away from the faulty valve of James Spaith. A million-dollar robot known as da Vinci would be holding the tools.
The surgical team began preparations before dawn for the patient's 7 a.m. arrival. Because the da Vinci robot is still relatively new -- this was to be Massimiano's 38th procedure with it -- several observers also gathered in the operating room. In addition to me, these included Jim Burgess, a neurosurgeon at Inova Fairfax; Kevin Cleary, a Georgetown University School of Medicine researcher specializing in the role of robot systems in medicine; and Jack Wesley, a representative from Intuitive, the company that makes the da Vinci.
When Massimiano arrived, Burgess greeted his friend with, "I'll be staying out of the way, but of course you'll be staying out of the way, too!"
Spaith's role in the leading edge of surgical technology came as a complete surprise. At age 40 and in apparently perfect health, he went for a routine physical in December and heard his doc utter a chilling aside: "I don't remember your murmur being this loud." Spaith had learned of the heart murmur 18 months earlier, when he underwent a new-patient exam, but the decision then was to just watch it. Now he needed a cardiologist. Urgently.
An echocardiogram showed that a badly damaged mitral valve was letting a large backflow of blood into the left atrium. (Blood normally flows from the left atrium, through the mitral valve, into the left ventricle, and then out into the aorta.) Left untreated, the condition would inevitably result in heart failure. Given the size of the reverse stream of blood, there was no time to wait.
"I didn't feel like anything was wrong," Spaith said, probably because he was relatively young and otherwise fit. Nonetheless, heart surgery was about to interrupt his life.
He researched his options. Conventional open heart surgery would require breaking open the sternum -- the long bone in the middle of the chest -- to get to the mitral valve. A newer, less invasive alternative reduced the considerable pain and recovery time by going between the ribs, using much smaller instruments and a thoracoscope (a fiber-optic scope inserted into the chest). The valve repair is identical, but no bones need be broken. Spaith was all for that.
But by the time he found Massimiano, he'd learned that the da Vinci was particularly suited for just his kind of surgery.
Massimiano told him da Vinci had the advantage of providing a three-dimensional view of the heart, compared with a thoracoscope's two dimensions. In addition, he said, the da Vinci overcomes a fundamental drawback to thoracoscopic surgery: The optics produce a mirror image on the monitor that the surgeon uses to guide his instruments; as a result, to make a stitch going left to right on-screen, for example, he must make his hands work right to left.
"The da Vinci corrects that," said Massimiano, "and since it gives me a better image besides, it's far superior to the standard minimally invasive techniques."
Armed and Able
Inova Fairfax's OR 17, a cardiac operating room, has more big overhead monitors than a sports bar. Two showed a large plus-sign against a black background, looking like some sort of MTV icon. Two more showed horizontal lines in several colors and sprang to life at 7:10 as nurses placed leads on Spaith's trunk and limbs: The EKG reading produced a white line; blood pressure, red; oxygen content, yellow; a few more monitors were reserved for tracking the "deep" lines that would later be inserted into the major arteries and veins.
Spaith's nervous commentary fell silent as the anesthesiologist got to work, injecting sedatives through an IV. One more monitor came alive as a sonography probe went into Spaith's esophagus and began feeding live images of the beating heart to a screen where Massimiano could see it at all times. A bulky heart-lung bypass pump, which during surgery replicates the lungs' job of exchanging carbon dioxide in the blood for oxygen, was rolled into place at 8 a.m. when, as scheduled, the first incision was made into the right side of the chest.
Massimiano narrated his every move. "The rib space is about two centimeters wide, and our port [opening] takes up just that amount of space. It's much nicer for the patient if you don't have to crack the sternum or spread the ribs. [Patients] recover much faster from minimally invasive procedures, and they run a much lower risk for post-op infection."
Over the next hour, while Massimiano continued to lay in the foundations for the valve repair, Cleary talked about the developing roles of robots in medicine.
"A surgical robot," as defined by the Robotic Institute of America, he explained, "is basically a reprogrammable arm. It has joints and a hand, called the end-effector, that allows you to put on any surgical tool you need. Unlike, say, the auto industry, where the programming is controlled by software, here the surgeon controls the arms in real time."
To sci-fi fans, da Vinci's appearance may come as a letdown. Forget "Lost in Space," forget R2D2, forget anything by Isaac Asimov. The da Vinci robot comprises three bulky machines. There is a surgeon's control console -- a rounded, gray-and-blue hulk where the surgeon sits to operate a joystick and foot pedals. There's an image processing console, essentially a rack of computers and processors. And there's the surgical cart itself, whose three long arms loom over the operating table like an oversize spider.
For the time being, all three pieces were in the OR. Technically, though, only the spider is needed up close.
Inova bought the da Vinci with research funds, and the benefits are still being identified. Its clearest advantage over open-heart surgery was the one Massimiano had mentioned -- shorter recovery and post-op time. So far, the advantages it offered over traditional thoracoscopic surgery were limited to the far less quantifiable gains in the surgeon's satisfaction: no more need to be ambidextrous or try to eliminate hand tremors. Massimiano envisioned further gains as experience grew with the robot. For now, though, the procedure -- fixing the damaged valve -- remains the same, so surgeons have not needed to re-learn any new critical procedures.
At 8:35, Massimiano gave the green light to go on bypass. Immediately, shoots of bright red snaked into the heart-lung machine while overhead the displays reflected the patient's altered physiology as blood was rerouted away from the heart. Through the incision, the heart could be seen pumping normally, even though the blood flow was diminishing rapidly.
Massimiano studied the data, directed the perfusionist to reduce the heart's blood flow further, then placed one last catheter into the root of the aorta, just above the heart. This would deliver the cardioplegia, a potassium concentrate that would stop the heart from beating. For the duration of the valve repair, the bypass machine would keep the body alive, while the resting heart received its delicate repair. Watching his progress on the bedside heart-sono, Massimiano liked what he saw and at 9:15 he arrested the heart.
Remote Control
Now the robot assumed center stage. Massimiano left Spaith's side and moved to the control console, as a nurse quickly guided the three robot arms into the surgical field.
Massimiano stripped off his gloves and sterile gown and seated himself inside the console, a yard from the patient and the sterile surgical field. He removed his shoes and socks, too, so he could work the foot pedals more precisely.
Two arms reproduced Massimiano's movements at the controls, while the third supported the double-lens camera that would feed images of the procedure to the control cart. The monitors overhead displayed a 3-D roller-coaster whoosh through the chest cavity, halting abruptly at what looked like a whitish pair of clamshells: the mitral valve.
The robot arms began to weave and turn as he assumed the controls, a soft, electronic whirr accompanying each move, manipulating the tiny tools buried inside the patient's chest. On a screen, a black-and-silver forceps could be seen exploring one of the clamshells, picking up a central piece of tissue, rolling it back and forth. Massimiano was studying the damage.
A second surgeon, Jamel Akrout, and a pair of nurses joined da Vinci at Spaith's side, and the anesthesiologist was at his post at the head, but the heart was being manipulated by a robot.
Burgess, the neurosurgeon, uttered a low "unbelievable," Cleary, the engineer, tsked in appreciation, and Massimiano called us over to give us each a look from the console. (Neither observers nor console were sterile.) The image on the overhead monitor was strikingly detailed, but the panoramic view from inside Massimiano's console was breathtaking. The valve leaflets dived at a steep arc, the pink supporting tissues stood above like dunes on a beach, and the robot's tools hovered over a pile of whitish tissue. Even a novice could see what needed to be fixed.
Roughly two hours into the procedure, Massimiano turned to what he does best: evaluating and repairing the damaged valve.
Under normal circumstances, during the portion of the pump cycle known as diastole, each of the two leaves, one anterior, one posterior, is pulled open by three cords, allowing blood into the ventricle. The center cord of Spaith's posterior valve had blown, and the middle portion of the leaflet had stretched itself flaccid. The remaining cords and tissue, however, looked to Massimiano to be in good shape.
Massimiano had outlined the likely scenarios for Spaith prior to surgery. In the best circumstance, he would remove the middle portion and sew the two ends together. If the resulting architecture allowed good valve closure, his job was done. If, on the other hand, the remainder of the leaflet looked unhealthy or if he was unable to achieve a closure that would prevent blood backflow, he would have to remove the valve entirely. That would leave two options: Replace it with a pig valve, which would need replacement in 10 years or so. Or install an artificial valve, which would commit the patient to taking Coumadin, an anticoagulant, for the rest of his life. "And live like a hemophiliac," as Spaith put it.
A fair amount, therefore, was riding on the next several minutes.
Massimiano's skill and judgment as a surgeon were the determining factors, and he had 20 years of experience to draw on. But using the da Vinci introduced one subtle difference. "You lose tactile feedback. I know a good stitch when I feel the needle go through the tissue, but with the da Vinci you soon begin to feel it with your eyes. You begin to perceive strength and tension based on visual, not tactile, clues. That's the amazing change. You feel it with your eyes."
Jack Wesley, the Intuitive rep, asked if he would like a software package to simulate the feel of the tissue, like a joystick vibrates and hums for kids' video games. Massimiano considered a few moments and shrugged. "I don't think it's that important anymore."
Massimiano kept up the narration as he worked. The tiny scissors in the robot's hand, which had at first looked to be just a probe for moving tissue back and forth, opened and began to snip away the loose leaflet and chord tissue. In a minute, the entire piece had been cut away, and Akrout took the damaged tissue from the robot.
The surgeon examined the remaining valve. He closed the scissors and pushed the two ends together, ultimately deciding to take out another wedge. His running commentary became choppy and fragmented, but ended with a relieved tone. "It looked huge on this 10x magnification, but now that I can see the base, it isn't as big a resection as it looked."
In other words, the valve looks savable.
Sewing Lessons
Massimiano replaced the scissors arm on the robot with a needle holder and fed a suture into its tiny jaws. On our two-dimensional monitor, the movements seemed awkward: pushing the curved needle down through the valve tissue, repositioning again to come up through the other side, looping and pulling to bring the two halves of the leaflet together. Another complex ballet to tie the knot. The arms on the robot itself swung widely, an odd contrast to the minuscule on-screen movements. As he clipped the two suture ends, Massimiano told us, "I have about 15 more stitches to go," in a tone conveying that we were about to get bored.
Which proved to be absolutely correct. For the next 50 minutes or so, until about 11:10, he repeated the same set of motions as he gently re-sculpted the valve into a shape that would withstand 30, 40 or more years of beating.
"You can move the robot arm better than your own," Massimiano said, as he described some advantages of using the da Vinci. "It eliminates tremor, and at the end of a long instrument in a small hole, that makes quite a difference. Plus, I can be as good with my left hand as my right, which makes me immediately ambidextrous. You get better at moving instruments without hurting the surrounding tissue."
A distinct disadvantage, he said, is that sewing takes longer than it would in an open heart case. The patient stays on the heart-lung pump longer and the bloodstream accumulates more anticoagulants and other agents, which take longer to recover from. Using clips would be better, but Massimiano has not yet worked with them. A real breakthrough, he speculated, would be the development of a tissue glue that could be relied on for years of normal living; no such thing yet exists. Massimiano considers the sewing problem a small tradeoff for the overall gains in precision and accuracy.
With the valve repaired, Massimiano got up from the console and headed out of the OR to re-sterilize. The robot was essentially done, but Massimiano still had a long way to go. Standing by Spaith's side once again, he flushed fluid from a bulb syringe into the ventricle: A direct look, with confirmation on the sono overhead, showed no backflow and good valve anatomy. So far, so good. He called for the robot arm to be pulled back from the patient's side and began sewing the outer lining of the heart back together, using his own two hands once more.
By 11:30, he told the perfusionist to prepare to restart the heart, and he withdrew the catheter from the aortic root. With the heart closed completely, he delivered an electric jolt from a defibrillator, and Spaith's body jumped a fraction of an inch. The tracings on the physio-monitors sprang back to life, and from the view hole, the pulsing heart could once more be seen. Massimiano's eyes were fixed on the sono images. They showed no return blood flow, a perfect alignment of the two leaflets against one another. Massimiano kept a steady watch on the monitors as the heart returned to full function, the heart-lung pump emptied and Spaith's circulation returned to full capacity. At 12:30, he pulled his gloves off, satisfied with the day's repair.
Walking to the ICU to check on his other patients later, Massimiano suddenly stopped and said, "You know what I love?" His face lights up like a kid's and his eyes gleam. "That whoosh when the camera dives right into the chest and you can see the valve right in front of you. That part's cool."•
J.B. Orenstein is an emergency room physician at Shady Grove Adventist Hospital in Rockville. His most recent story in this Standard Operating Procedures series was about surgery to repair cleft palates.
