Robots With Heart

Today, applications include mitral valve repair, revascularization,
By: 
Richard R. Rogoski

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May 23, 2006

Minimally-invasive surgery has proven to be safer, requires a shorter hospital stay and is cosmetically preferred over conventional surgery because the incisions are much smaller.

But while procedures such as a laparoscopic cholecystectomy (gall bladder removal) have become commonplace since the 1980s, cardiothoracic surgeons have largely relied on traditional methods, not the least of which is cracking open a patient's chest in order to fully expose the heart.

That, however, is changing as more surgeons are beginning to see the benefits of using microsurgical instruments that are attached to highly maneuverable robotic arms.

As demand for these robotic systems increase, there are fewer options available. The dominant player in the field is Sunnyvale, CA-based Intuitive Surgical Inc., whose da Vinci Surgical System is now being used worldwide.

Mitral Valve Breakthroughs

One of the pioneers in the refinement of the da Vinci Surgical System is W. Randolph Chitwood, M.D., director of the East Carolina Heart Institute and professor of Surgery at the Brody School of Medicine, East Carolina University, Greenville, NC.

Dr. Chitwood recalls the skepticism he and other cardiac surgeons faced when they began to believe that minimally-invasive surgery could be used in heart surgery.

“People said you could take a gall bladder out but you'll never be able to attach small vessels. You need tactility,” Dr. Chitwood said.

But because the robotic system uses a miniature camera, which is inserted into the center incision of the three tiny ones made in the chest, he noted, “Eighty percent of your cues are visual, so you can develop a kind of visual tactility.”

Dr. Chitwood says by 1996 he was convinced certain procedures could be done endoscopically.

“We started redesigning instruments and showed we could do mitral valve repairs using 'chopstick' instruments,” he said.

“In about 1997, I presented our findings at a conference in Minnesota and was approached by an engineer from Intuitive Surgical,” he continued. “I went to California and worked with the prototype for a few days, then took the robot to Leipzig and did four cases there to show its efficacy.”

Back in the U.S., the FDA allowed the system to be tested on 10 patients, then approved a multicenter study involving five universities, he says.

In 2001, the da Vinci system received FDA approval. “Then we started training people,” Dr. Chitwood notes. “So far, we've trained over 300 surgeons worldwide.”

Training cardiothoracic surgeons on the system is not hard, he says, but they have to already have some experience. “If you're a good mitral valve surgeon, doing more than 50 a year, you can reach comfort level at 10 and expertise at 25.”

At East Carolina, Dr. Chitwood and his team have already performed over 270 mitral valve repairs using the system, he says.

To assist in the training of other surgeons, a second control console can be hooked up in a dual-control situation similar to the dual controls found in driving school automobiles, he says. Training could be made a lot easier, though, if there was a full-size simulator like those used by airline pilots.

Repairing the mitral valve, or “inflow valve” for the left ventricle of the heart, usually is required to treat regurgitation (leakage) or stenosis (narrowing) of the valve. Conventional methods entail performing a sternotomy (splitting of the breastbone) in order to gain entry into the chest cavity.

But the da Vinci system gives surgeons access to the heart through only three small (usually one to two cm) incisions. The system itself consists of two major components: the surgeon's viewing and control console and the surgical arm units that position and maneuver detachable and interchangeable surgical instruments. The pencil-sized instruments, which include computer-enhanced mechanical wrists, are designed to provide the dexterity of the surgeon's forearm and wrist at the surgical site.

Marc R. Katz, M.D., is a cardiothoracic surgeon with Cardiac & Thoracic Surgical Associates and at Henrico Doctors Hospital, which is located just outside Richmond, VA. He also was one of the surgeons whom Dr. Chitwood trained on the da Vinci system.

Dr. Katz says that patients who undergo cardiac surgery involving a sternotomy are usually in the hospital for five to seven days, versus two and a half days when the surgery is performed using the robotic system.

Lelan G. Siwek, M.D., a cardiothoracic surgeon with Northwest Heart & Lung Surgical Associates and at Sacred Heart Medical Center in Spokane, WA, says hospital stays are shorter and recovery times are faster because there's no bone to heal. “Most people can get back to work and physical activity, even sports, in as short a time as a couple of weeks.”

A da Vinci user for about four years, Dr. Siwek says in 2005 he performed 58 robotic procedures, of which 37 were mitral valve repairs. In the first three months of 2006 he's already performed 16 mitral valve repairs.

Robotics and Revascularization

But mitral valve repair is not the only procedure for which the da Vinci system is proving to be invaluable. Hybrid revascularization, the marriage of percutaneous intervention and robotic-assisted revascularization is developing into a solid treatment model for multivessel coronary artery disease.

This type of bypass surgery involves the detachment and then reattachment of the left internal mammary artery — a procedure that until recently was done only through open-chest surgery.

Dr. Siwek says that because this robotic-assisted procedure is still relatively new, his hospital is one of 12 trial sites in which the da Vinci system is being used.

On the other hand, the proven success of the da Vinci system in mitral valve repair has helped Sacred Heart Medical Center become a major West Coast training facility for cardiothoracic surgeons.

The systems aren't cheap, though. Dr. Chitwood says a complete da Vinci system costs over $1 million. But he adds: “I think we're on the cusp of a new horizon. With very few modifications, it can become a standard.”

Keeping Pace

Pacemakers have been around for decades and have been unquestionably effective in stabilizing the heartbeats of millions of people who go on to live normal, active lives. But a new procedure that uses a robotic surgical system to facilitate the connection of leads is gaining wider acceptance.

Called cardiac resynchronization therapy (CRT), or biventricular pacing, the procedure uses standard pacemaker technology but with a special third lead to sense and pace the left ventricle. This allows the pacemaker to provide outputs to both the left and right ventricles simultaneously in order to restore synchrony and allow the ventricles to pump more efficiently.

In the typical placement of a pacemaker using standard percutaneous methods, this third lead is placed via the coronary sinus into a vein on the back of the heart. By using a robotic surgical system, surgeons have been able to attach the third lead to the wall on the outside of the heart, thereby ensuring that the pacemaker is successfully implanted. However, it's been reported that 15 to 20 percent of the time this vein is inaccessible.

The first robotic-assisted surgery of this type performed in the U.S. was done at St. Luke's-Roosevelt Hospital Center in New York City using the da Vinci system.

Present Yet Distant

The operating room is not the only place where robotic technology is finding a home in hospitals. Mobile robots that serve as the eyes and ears of physicians are now being used extensively in emergency rooms, intensive care units and catheterization labs.

Andrew Schwartz, M.D., a cardiothoracic surgeon and chairman of the division of cardiothoracic surgery at Shawnee Mission Hospital in Overland Park, KS, says he uses such a robot for late-night rounds and to help him make a diagnosis when he's unable to be with the patient.

Dr. Schwartz originally had been using the RP-6 Remote Presence Robot developed by Santa Barbara, CA-based InTouch Health, but has since upgraded to the RP-7 model.

“The RP-7 has improved visibility so you can see the floor and where you're going at the same time,” he says. “I can also zoom in with a mouse and do not have to use a keyboard.”

Under the direct control of the physician, the RP-7 wireless robot can move anywhere untethered, allowing the physician to freely interact with patients, their families or other staff members. The built-in speakers, microphone, camera and viewing screen provide face-to-face interactions, even if the physician is miles away.

In addition, Dr. Schwartz noted, “The robot has a stethoscope attachment so I can listen to a patient's heart and lungs. The sound quality is so good, it's like being right at the bedside.”

Because the robot is controlled via its remote ControlStation, the physician has total control from anywhere in the hospital, office or home.

“I once got a call at 3 a.m. about a patient who had cardiac surgery the day before,” Dr. Schwartz recalled. “I drove the robot to the bedside and was able to see that the patient needed to go back into surgery. By the time I got to the hospital, the patient was prepped and the team was ready.”

Dr. Schwartz also says the robot has made rounding easier. “I round at night, about 10 p.m., so I am able to talk with patients and interact with the nursing staff,” he said, adding that using the robot for nightly rounds not only enhances patient care, “but it is enhancing my lifestyle.”

The mobility of the robot and its high-quality audio/video components has even turned it into a teaching tool, he says. “One surgeon actually brought the robot into the OR to watch an associate and to offer guidance.”

At a cost of about $155,000 for the robot and about $1,000 for the control console, this robotic system is affordable for most hospitals. Dr. Schwartz says Shawnee Mission Hospital now owns four — one of which is being used exclusively in the ICU.

And they have become part of the hospital's expansion plans, he says. “We're planning to build a second hospital, so we can link the two with these robots.”

Rich Rogoski is a free-lance reporter who can be reached at: rogoski@aol.com.

Sidebar

Magnetically Guided Catheter Zaps Atrial Fibrillation
Robotic device appears to be more precise than conventional catheter ablation devices (excerpts from an ACC press release, April 4, 2006)
A remotely-controlled catheter device guided by magnetic fields provides a safe and practical method for delivering radio-frequency ablation treatment in the hearts of patients with atrial fibrillation, according to a new study in the April 4, 2006 issue of the Journal of the American College of Cardiology.
“Based on our experience with remote navigation and ablation technology, a new era in interventional electrophysiology is beginning as magnetic, very soft catheters can be navigated in the heart more precisely and safely than manual catheters without risk of major complications, even in less experienced centers,” said Carlo Pappone, M.D., Ph.D., from the department of Electrophysiology, San Raffaele University Hospital in Milan, Italy.
Typically the radio-frequency pulse is emitted from the tip of a catheter threaded through blood vessels into the heart until it is positioned next to the target area. Conventional catheters are somewhat stiff, so they can be pushed and pulled through blood vessels and their tips can be curled and pointed by an operator standing by the patient. The device tested in this trial uses a very soft, limp tip that has a magnet on the end. Rather than manually pointing the catheter tip, the operator of this device uses a computer to control a magnetic field that robotically moves the catheter tip. The principle is the same as a compass needle pointing to magnetic north; allowing this device to steer the magnetic catheter in three dimensions to a target visualized on 3-D scans of the patient's heart.
This first trial of the robotic magnetic navigation system in patients with atrial fibrillation involved 40 participants whose conditions were not adequately controlled by medication. After encountering some difficulties in the first three patients, the researchers said the remaining procedures went smoothly.

In the Beginning: Tracing the Origins of Cardio-Robotics
Richard R. Rogoski
The prototype for the daVinci Surgical System by Intuitive Surgical Inc. was developed in the late 1980s at the former Stanford Research Institute, under contract with the U.S. Army. While initial funding was aimed at developing a system that could be used on the battlefield to perform surgeries remotely, it soon became apparent that other commercial uses were possible.
In 1995, Intuitive Surgical Inc. was founded and the da Vinci system had its official launch in 1999.
Another company that had made inroads in the cardio-robotic field was Santa Barbara, CA-based Computer Motion Inc. Founded in 1989, the company developed what it called the Zeus Minimal Invasive Surgical Robot System.
Things, however, did not go well for Computer Motion. In the fall of 2002 the company was sued by Intuitive Surgical, which alleged patent infringement. In March 2003, both companies announced that they were merging, thus putting an end to the litigation.
In a statement issued at the time of the merger, Lonnie Smith, Intuitive Surgical's president and CEO, said: “With these disputes behind us, we can focus the talent and energy of the combined organization on developing and growing the application of robotics to minimally-invasive surgery; the significant benefits we bring to patients, surgeons, and medical centers throughout the world; and the operating efficiencies that the combination will deliver to the bottom line.”
Facing stiff competition from the acknowledged leader, few companies seem to be willing to enter the fray. Norwalk, CT-based United States Surgical, which is a unit of Tyco Healthcare Group LP, says it continues to develop surgical devices and laparoscopic instrumentation for general and specialty procedures.

  • Dr. Andrew Schwartz uses the RP-7 by InTouch Health for late-night rounds and much more.
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