"This is surgery meeting the information age," says Ralph J. Damiano Jr., M.D., chief of cardiac surgery within the Division of Cardiothoracic Surgery at Washington University School of Medicine in St. Louis. "For the first time, we are integrating computers into the operating room to assist us in surgery. This may transform the way cardiac surgery is done in the future."

Damiano led the study, published in the June issue of Annals of Surgery. The first author was Sunil M. Prasad, M.D., postdoctoral surgery fellow.

During coronary artery bypass grafting, surgeons replace a clogged or diseased artery with a healthy blood vessel from another part of the body. The invasive features of the procedure increase recovery time and the risk of complications.

In order to access the heart, surgeons have to make a 12- to 18-inch incision in the chest and prop open the breastbone. This is one of the main sources of postoperative pain.

To eliminate the large surgical incisions, surgeons in other fields can use endoscopic tools inserted through small pencil-sized holes in the skin. But these devices are more than three times as long as traditional instruments and present several challenges to heart surgeons.

Imagine trying to sign your name with a 12 to 18-inch pen. You can do it, but your handwriting would probably be illegible. Moreover, these instruments are inserted through the chest wall, which becomes a fixed pivot point. As you move your hand to the right, the instrument tip deflects in the opposite direction. This fulcrum effect is counterintuitive and disorienting.

"Heart surgeons have steady hands, but it’s impossible to hold long instruments steady when you are working on very small vessels," says Damiano. "To date, performing endoscopic coronary artery surgery by hand has been impossible, beyond the limits of dexterity of any heart surgeon."

Damiano and others around the world have devised a way to avoid these problems by using the Zeus Robotic Surgical System produced by Computer Motion Inc. of Goleta, Calif. In the current study, Damiano’s team inserted two surgical instruments and one endoscopic camera into each patient through three small incisions.

The surgeon sat at a computer console in the same room as the patient. The console consisted of a video monitor, a computer control system and two instrument handles. When the surgeon moved the handles, the computer rescaled the motions, filtered out hand tremors and relayed the digitally-perfected movements to two robotic arms with specialized instrument tips. Simple voice commands controlled the robotic arm holding the video camera.

The surgeries were performed at Pennsylvania State University. Of 28 patients enrolled in the study, 19 qualified for robotically assisted grafts. The robotic procedure was used to graft the left internal thoracic artery onto the left anterior descending artery. Most patients also received at least one other graft via traditional surgical techniques.

The researchers reported no difficulties in assembling the robotic system safely and quickly. The system functioned properly in all 19 procedures without any device-related complications. Grafts in two patients provided inadequate blood flow because of failures in surgical technique. In both cases, the surgeons were able to quickly convert to manual surgery and successfully repair the grafts.

The grafts of all 19 patients were functioning properly after two months, as assessed by coronary angiography. Phone interviews one year after surgery revealed that all 19 were still free of symptoms.

"Our results show that the most difficult part of the procedure can be performed endoscopically with robotic assistance," says Damiano. "The robotic system addressed many of the physical limitations of traditional endoscopic surgery in the microsurgical setting, and it clearly enhanced our dexterity and performance. It is encouraging that there have been no complications after one year, though this still represents short-term results."

In the future, Damiano hopes to combine the endoscopic robotically assisted procedure with new beating-heart surgical techniques. By eliminating the need for the heart-lung machine and the large incision in the chest, this approach is likely to shorten recovery time.

Funding from Computer Motion, Inc. supported this research.

(Reference: Prasad SM, Ducko CT, Stephenson ER, Chambers CE, Damiano RJ. Prospective clinical trial of robotically assisted endoscopic coronary grafting with 1-year follow-up. Annals of Surgery, 233, 725-732, June, 2001.)

[Contact: Gila Z. Reckess]

29-May-2001