Robots Lend a Helping Hand to Surgeons

Surgery News & Resources

Robots Lend a Helping Hand to Surgeons
by Michelle Meadows

Robot-assisted surgery is the latest development in the larger movement of endoscopy, a type of minimally invasive surgery--the idea being that less invasive procedures translate into less trauma and pain for patients. Surgery through smaller incisions typically results in less scarring and faster recovery. It's not that robots are changing the basics of surgery. Surgeons are still cutting and sewing like they have been for decades. Robots represent a new computer-assisted tool that provides another way for surgeons to work.

Rather than cutting patients open, endoscopy allows surgeons to operate through small incisions by using an endoscope. This fiber optic instrument has a small video camera that gives doctors a magnified internal view of a surgical site on a television screen.

In abdominal endoscopy, known as laparoscopy, surgeons thread the fiber optic instrument into the abdomen. First performed in the late 1980s, laparoscopy is now routine for many procedures, such as surgery on the gallbladder and on female organs.

With robotic surgical systems, surgeons don't move endoscopic instruments directly with their hands. Instead, surgeons sit at a console several feet from the operating table and use joysticks similar to those used in video games. They perform surgical tasks by guiding the movement of the robotic arms in a process known as tele-manipulation.

The Food and Drug Administration reviews data on the safety and effectiveness of robotic software and hardware and requires manufacturers to implement training programs for surgeons. The FDA also monitors experimental uses for robotic applications, including clinical trials for robotic heart surgery. It's too soon to say for sure how far and how fast robotic surgery will grow, but experts say the future looks promising.

On the Market

Two robotic surgical systems have received FDA clearance to be marketed in the United States: The da Vinci Surgical System, made by Intuitive Surgical, Inc. of Sunnyvale, Calif., is cleared to perform surgery under the direction of a surgeon. The ZEUS Robotic Surgical System, made by Computer Motion, Inc. of Goleta, Calif., has been cleared by the FDA to assist surgeons.

"[The] da Vinci is cleared to assist in advanced surgical techniques such as cutting and suturing [sewing]," says Neil Ogden, chief of the FDA's General Surgery Devices Branch in the Center for Devices and Radiological Health. "ZEUS is cleared to assist in grasping, holding, and moving things out of the way, but isn't cleared for cutting or suturing." Clinical trials on ZEUS are underway with the goal of obtaining FDA clearance to assist in the performance of advanced surgical tasks in the United States, according to Paul Nolan, senior director of customer training and education at Computer Motion.

Here's a profile of each system:

The da Vinci Surgical System

In July 2000, the FDA cleared da Vinci as an endoscopic instrument control system for use in laparo-scopic (abdominal) surgical procedures such as removal of the gallbladder and surgery for severe heartburn. In March 2001, the FDA cleared da Vinci for use in general non-cardiac thoracoscopic (inside the chest) surgical procedures--surgeries involving the lungs, esophagus, and the internal thoracic artery. This is also known as the internal mammary artery, a blood vessel inside the chest cavity. In coronary bypass surgery, surgeons detach the internal mammary artery and reroute it to a coronary artery. In June 2001, the FDA cleared da Vinci for use during laparascopic removal of the prostate (radical prostatectomy).

The da Vinci is intended to assist in the control of several endoscopic instruments, including rigid endoscopes, blunt and sharp dissectors, scissors, scalpels, and forceps. The system is cleared by the FDA to manipulate tissue by grasping, cutting, dissecting and suturing.

In use, a surgeon sits at a console several feet away from the operating table and manipulates the robot's surgical instruments. The robot has three hands attached to a free-standing cart. One arm holds a camera (endoscope) that has been passed into the patient through small openings. The surgeon operates the other two hands by inserting fingers into rings.

The arms use a technology called EndoWrist--flexible wrists that surgeons can bend and twist like human wrists. The surgeon uses hand movements and foot pedals to control the camera, adjust focus, and reposition the robotic arms. The da Vinci has a three-dimensional lens system, which magnifies the surgical field up to15 times. Another surgeon stays beside the patient, adjusting the camera and instruments if needed.

There are 50 da Vinci systems placed in U.S. medical centers, 34 placed in Europe and five placed in Asia.

ZEUS Robotic Surgical System

The FDA cleared ZEUS in October 2001 to assist in the control of blunt dissectors, retractors, graspers, and stabilizers during laparoscopic and thoracoscopic surgeries.

ZEUS has three robotic arms that are mounted on the operating table. One robotic arm is called the Automated Endoscopic System for Optimal Positioning Robotic System (AESOP). AESOP is a voice-activated robot used to hold the endoscope. The FDA cleared AESOP to hold and position endoscopes in 1994, and voice activation was added later. ZEUS differs from the da Vinci system in that the AESOP part of ZEUS responds to voice commands. For example, a surgeon might say: "AESOP move right." The positioning arm then would move right until the "stop" command was given.

Like the da Vinci system, the other two arms of ZEUS are the extension of the left and right arms of the surgeon. Surgeons sit at a console and wear special glasses that create a three-dimensional image. Computer Motion has added a flexible wrist technology called Micro-Wrist, which is now included in FDA-approved clinical trials, Nolan says.

There are currently more than 30 ZEUS units installed in North America, 15 units installed in Europe and the Middle East, and five units installed in Asia. 

So Why Use Robots?

Along with helping surgeons perform minimally invasive surgical tasks, robots have superhuman capabilities that make surgery easier, says Paul Massimiano, M.D., a cardiac surgeon at Inova Fairfax Hospital in Virginia. He has performed thoracic and experimental cardiac surgery using the da Vinci system.

"Robotic arms don't have tremor," so they can remain steady at all times, Massimiano says. Robotic wrists make it easier for surgeons to manipulate tissue and work from all kinds of angles. "I can reach around and get to places that would be harder to get to otherwise," Massimiano says.

Robotic surgical systems can also improve depth perception, giving surgeons three-dimensional vision, compared with the two-dimensional vision they would normally get with endoscopic procedures. And the surgical field can be magnified so that millimeter-sized veins appear as big as pencils.

Compared with the long instruments used in endoscopy, robotic surgical systems use smaller instruments that provide increased range of motion. Celeste Hollands, M.D., chief of pediatric surgery at Louisiana State University's Health Sciences Center in Shreveport, sees this as a huge benefit in her work with small children.

"A baby's abdomen is only about the size of your hand, so the instruments need to be small enough," Hollands says. She used Zeus' 5-millimeter scope to help correct stomach blockages in three babies earlier this year.

"I had to cut manually," she says, "but ZEUS stabilized the intestines for me and spread stomach muscles. I was able to easily move back and forth from manipulating ZEUS to using a standard laparoscopic procedure."

Robotics also offers motion scaling, which means that a surgeon's gross hand movements can be reduced to fine movements, allowing for accuracy in tight spaces. For example, with motion scaling, one inch of movement by the surgeon results in a quarter-inch movement by the robotic surgical instruments.

Hollands only had to make a tiny nick in the abdominal wall to perform the surgeries, and the babies' scars were hardly noticeable. "When they came back into the office, I had to look hard to figure out where the scars were," she says.

Robotic Heart Surgery

Cardiac surgery was the last area to adopt endoscopic procedures because of the complexity of the procedures involved. But starting around 1995, heart surgeons were successful in using Computer Motion's AESOP to help repair and replace narrowing or leaking cardiac valves with small incisions.

"It was video direction of operations via a voice-activated robotic camera that introduced cardiac surgeons to the robotic age," says Marco Zenati, M.D., assistant professor of surgery at the University of Pittsburgh.

W. Randolph Chitwood Jr., M.D., chairman of the department of surgery at East Carolina University in Greenville, N.C., says he and his colleagues have done more than 200 mitral valve repairs using AESOP.

"This has allowed our surgeons to have greater flexibility in repairing complex mitral valve problems, as well as to replace valves," Chitwood says. "In fact, we have been able to work deep within the heart using AESOP to close fistulas between coronary arteries and the cardiac chambers--all done using voice-activated AESOP camera control and secondary vision from a monitor."

AESOP is cleared for use as a voice-activated camera in heart surgery. But complete robotic heart surgery, which is commonly done in Europe and Canada, is considered experimental in the United States. Both da Vinci and ZEUS are being used in clinical trials studying endoscopic cardiac surgery. Through what's known as an investigational device exemption, companies can conduct FDA-approved clinical trials to collect safety and effectiveness data on robotic heart surgery.

The goal is to avoid the tissue damage that comes with making a foot-long incision through the sternum and opening up the chest, which has been the typical procedure for open-heart surgery. With robot-assisted heart surgery, surgeons are able to operate through three small incisions between the ribs. Preliminary data suggests that recovery time may be shortened with robotic-assisted heart surgery.

In May 2000, Chitwood used da Vinci to perform the first complete mitral valve repair in the United States as part of a multi-center, FDA-approved trial sponsored by East Carolina University and Intuitive Surgical. A total of 10 centers are participating, including the University of Southern California in Los Angeles, Columbia Presbyterian Medical Center in New York, Brigham and Women's Hospital in Boston, and Inova Fairfax Hospital in Fairfax, Va. Patients in the trial have defective mitral valves repaired with assistance from the da Vinci system. Chitwood and his colleagues have done 41 mitral valve repairs with da Vinci with no major problems to date.

"Our initial experience shows this can be done with good patient outcomes," says Chitwood, who serves as the trial's principal investigator. "Our patients have had better cosmetic results and spent less time in the intensive care unit and hospital compared to conventional mitral valve surgery, which cuts the breastbone in half."

While East Carolina University leads the multi-center mitral valve trial in which da Vinci is being evaluated, Columbia will lead a multi-center trial on coronary artery surgery with da Vinci. Previous clinical trials investigating robotic assistance in coronary surgery appear promising, surgeons say. For example, Ralph Damiano of Washington University in St. Louis has reported successful results in U.S. clinical trials involving coronary artery bypass surgery using the ZEUS system. This operation typically requires stopping the patient's heart and using a heart-lung machine, which maintains circulation and takes over breathing for the patient.

In April 2001, Zenati and his colleagues used ZEUS during a beating-heart cardiac bypass operation on a 63-year-old man. This was part of an FDA-approved multi-center trial investigating whether ZEUS can be safely used to help surgeons connect the left internal mammary artery graft to the left anterior descending artery.

"This is something that can't be done with standard laparoscopy," Zenati says. "We're talking about connecting tiny blood vessels that are only 2 millimeters, so there is little margin for error."

What Can Go Wrong?

From a regulatory standpoint, the FDA pays close attention to the potential for error and whether robotic equipment meets performance standards, says Ogden. "We evaluate the possibility of technical failure of the computer and whether it translates into any risk for patients."

So far, there haven't been indications that robotic surgery is any riskier than standard laparoscopic procedures. And there haven't been any patient injuries or deaths related to robotic system failures.

Chitwood says there is always a risk of technical difficulty when it comes to automated products. But there are also fail-safe mechanisms that help protect against problems. "[The] da Vinci will make a dinging noise if your head isn't engaged in the right place," he says. "And if it isn't engaged in the right place, then you can't make any movements."

Experts say there may be times when the surgeon will begin a surgical procedure with the robot and then for one reason or another have to abandon it and do the surgery using traditional methods. "But that's not bad," says Vaughn A. Starnes, M.D., Hastings professor and chairman of the department of cardio-thoracic surgery at the Keck School of Medicine, University of Southern California (USC).

"We would just switch if we needed to and go to a conventional surgery," which surgeons say matches the care patients would otherwise receive. "We might get in there and realize the robot can't be used because of anatomical reasons such as if the atrium is too small," says Starnes, who uses da Vinci as part of the multi-center mitral valve study. 

Ogden says other important safety-related questions include: How much longer does it take to perform a procedure with robotic assistance? And, is the time difference significant? Studies of da Vinci indicate that surgery using the robotic device took about 50 minutes longer--nearly twice as long as with standard laparoscopic surgery. The increase in length of time is largely attributed to lack of experience with the new technology. "Eventually, we would like to see that the operative times are similar to the standard times," Ogden says.

Massimiano says doctors carefully evaluate whether a patient can take a longer surgery. "We won't use the robot if we believe a patient can't stay on the heart-lung machine for a certain length of time."

The Learning Curve

The FDA requires manufacturers to train surgeons before they can use robotic surgical systems on patients. Ogden says there is a significant learning curve involved. "As it stands now, it takes 12-18 patients before surgeons feel comfortable and before surgeons are able to perform the procedures as quickly as with standard techniques," he says.

Paul Nolan of Computer Motion says typical training for surgeons who buy the ZEUS system involves up to 40 hours, including experience at animal and cadaveric labs. "We believe we presently have a solid surgeon training regime for ZEUS customers, and we are also actively improving the whole training program for our products," Nolan says.

In terms of ZEUS, he says, these improvements include a program covering technical training, operating room choreography, sterility, and enhanced hands-on lab training modules based on a surgeon's endoscopic skill level.

Training involves having surgeons come to the company's headquarters and training at hospitals. The same idea is used for da Vinci, which has four active training centers, according to Gene Nagel, director of training at Intuitive Surgical. The company offers two- and three-day da Vinci training programs based on different surgical specialties.

"Our core focus is team training," Nagel says. "For nurses, it's preparation, intraoperative and postoperative system management. For surgeons, it's training to the necessary skills to become facile in using da Vinci in a variety of surgical applications."

"More than this being a hard technique to learn," says Massimiano of Inova Fairfax Hospital, "it requires adjusting your approach to the surgery and your way of thinking. The robot is your assistant now, and that takes some getting used to."

Chitwood agrees. He says, "There is a mental challenge of moving from a large incision where you can directly see things and touch the patient to operating through small incisions with less direct control. But I tell surgeons they have even more control because the robot is more precise. It's a matter of accepting that you don't have to see with your eyes directly. You can look through a scope."

Because of limited data, it is hard to convince doctors of this, Chitwood adds. "We teach that if you do this and become uncomfortable, you can always go back to a conventional approach."

Chitwood's center at East Carolina University was the first U.S. site to formally train surgeons in clinical robotics and has trained more than 170 surgeons. They use a curriculum that trains surgeons for two to three days in cardiac, gallbladder, and gastric reflux surgery. The center is developing similar programs for gastric bypass and gynecologic operations.

When it comes to training heart surgeons in robotic surgery, Zenati calls it "uncharted territory." Surgeons in disciplines that have commonly used endoscopy and young surgeons, who are most likely to have experienced laparoscopic or video-assisted thoracic training in residencies, may have an easier transition to robotics. Most cardiac surgeons have no experience with endoscopic techniques. "So is this going to become mainstream for us or will just a small subset of doctors continue to do this?" Zenati says. "It's too soon to know."

Toward the Future

Zenati says the current robotic surgical systems are just the beginning, "like Model Ts," he says. The products will likely evolve to correct their limitations. For example, da Vinci and ZEUS have "force feedback" for gross movement, but not fine movement.

"If you use an instrument and touch tissue, you feel a different resistance," Zenati says. "Without force feedback, you can push but you don't know how hard you are pushing with the robot." Often sight can compensate for touch, but force feedback remains an area that needs more attention.

Starnes of USC says the drive toward wider use of robotic surgery won't come from doctors, many of whom are used to doing surgery the traditional way. And the cost of the systems also may affect which hospitals can adopt the new technology. The da Vinci sells for about $1 million; ZEUS is priced at $975,000.

"Over time, I think patients will demand it," Starnes says. "A lot of patients getting mitral valve operations are in their 40s and 50s, and they are usually very concerned about recovery and getting back to work."

Massimiano says in his experience, patients have been enthusiastic about robotic surgery. "They perceive new devices as being better."

Anita Veltman, 66, of Sterling, Va., says she had laparoscopic gallbladder surgery and knew the benefits of minimally invasive surgery. So she felt comfortable about having the da Vinci robot successfully remove her mammary artery as part of preparation for bypass surgery at Inova Fairfax Hospital in October 2001. "I was not afraid of it," she says. "I asked for the robot. All I could do was put my trust and faith in the doctors."

Robotics and Telesurgery

The da Vinci and ZEUS make it possible for surgeons to perform robotic surgery across long distances. Surgeons from the European Institute of Technology used ZEUS and high-speed telecommunications to perform the first complete long-distance robotic surgery last year. According to an article in the Sept. 27, 2001, issue of the journal Nature, the surgeons worked from New York to remove the gallbladder of a 68-year-old woman in Strasbourg, France.

The mean total time delay was 155 milliseconds, so surgeons could see the result of their commands a little more than one-tenth of a second later. The time to set up the robot was 16 minutes and the gallbladder was dissected in 54 minutes without complications. This is similar to the time it takes to perform standard laparoscopic gallbladder surgery. Mount Sinai Medical Center in New York and the Department of Electrical Engineering at the University of California participated in the study. Researchers first practiced the procedure on pigs. --M.M.

U.S. Food and Drug Administration 
FDA Consumer magazine FDA/Office of Public Affairs

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