Robotically Assisted, Minimally Invasive Cardiac Surgery
Michael Argenziano, M.D.
Assistant Professor of Surgery
Columbia University College of Physicians and Surgeons
Director, Robotic Cardiac Surgery
New York Presbyterian Hospital
Columbia-Presbyterian Medical Center

Introduction

In the past decade, the face of cardiac surgery has been changed by a number of technologic advances, most notably the development of less invasive techniques, including minimally invasive direct coronary artery bypass (MIDCAB), off-pump coronary artery bypass (OPCAB), and minimal access valve surgery. However, each of these procedures has had a limited impact on the general practice of cardiac surgery for a number of reasons.

Initial attempts to perform cardiac operations through small incisions were hindered by the absence of appropriate accessory technology, such as visualization systems, retractors, stabilizers, and alternate methods of vascular cannulation and cardiopulmonary bypass. With the development of these technologies, surgeons have been increasingly able to perform complex cardiac procedures, including coronary artery bypass, mitral and aortic valve replacement, and atrial septal defect (ASD) closure, through smaller-than-traditional incisions. Nonetheless, in many cases, the extent to which incision size has been reduced by these minimally invasive approaches has been matched by a corresponding increase in technical difficulty and operative time, due to the constraints imposed by limited or incomplete cardiac exposure. For example, MIDCAB, in which a single vessel bypass to the anterolateral surface of the heart is achieved through a small anterior mini-thoracotomy, requires internal mammary artery graft harvesting by thoracoscopy, which even in the most experienced hands, is time consuming and technically challenging. Furthermore, the decreased visualization through small thoracotomy incisions has led to a significant incidence of complications with this procedure.

With respect to valvular surgery and other open-heart procedures (such as ASD repair), advances in the area of peripheral cardiopulmonary bypass access and endoaortic balloon technology ("port-access") have allowed these procedures to be performed through smaller-than-usual (but not necessarily small) incisions. The development of these procedures has required the adaptation of surgical instruments and techniques to the challenge of operating "in a deep hole," with less than optimal visualization. For these and other technical reasons, these procedures have been performed predominantly at selected centers, and have not gained widespread popularity.

Robotically-assisted cardiac surgery

The minimally invasive cardiac surgical movement has recently been propelled by the introduction of a new category of technologic achievement: the computerized telemicromanipulator. Utilizing this device, also known as the surgical robot, surgeons can manipulate small instruments, which are inserted through small chest incisions, in tight spaces, achieving many of the technical maneuvers previously possible only with open exposure. Since May 2001, cardiac surgeons at New York-Presbyterian Hospital have begun to utilize this technology, and are currently involved in several exciting clinical protocols testing the da Vinci™ Surgical System, manufactured by Intuitive Surgical, Inc. (Mountainview, CA) for a variety of cardiac surgical operations.

How the Da Vinci system works

The Da Vinci Surgical System™ consists of two primary components: the surgeon's viewing and control console and the surgical arm unit that positions and maneuvers detachable surgical EndoWrist instruments. These pencil-sized instruments (with tiny, computer-enhanced mechanical wrists) are designed to provide the dexterity of the surgeon's forearm and wrist at the operative site through entry ports less than 1 cm. This enables the surgeon to enter the chest through keyhole incisions and perform closed chest heart and lung surgery. One port allows access for the endoscope, a tiny camera that is attached to a fiber-optic cable. The other two ports provide access for surgical tools. Instead of the surgeon holding the tools, the robots wrists do -- bending back and forth, side to side, and rotating in a full circle -- thereby providing greater range of motion than humanly possible. The wrists of the robot mimics the motions made by the physician, who sits at a console outside the operating room. The surgeon peers through an eyepiece that provides high-definition, full-color, magnified, 3-D images of the surgical site provided by the endoscope. The physician moves his hands, which are attached to manipulation controls - and the robot follows along. An important element of this technology is that the built in computer enhances the surgeon's hand movement and renders it more precise with less tremors - an important element in refining delicate bypass and valve surgery.

Potential impact of robotic technology

Because the Da Vinci robotic surgical system allows for 3-D visualization and wrist-like dexterity and control of fine instruments that can be placed in the chest through post-sized incisions, this technology has the potential to impact the practice of cardiac surgery in three important ways:

1. Make existing MIS operations easier: Surgical procedures routinely performed today using MIS techniques will be performed more quickly and easily with the increased dexterity and control provided by robotic assistance.

2. Make difficult MIS operations routine: Surgical procedures that today are performed only rarely using MIS techniques may someday be achieved routinely with robotic assistance. Some procedures have been adapted for port-based techniques but are extremely difficult and are currently performed by a limited number of highly skilled surgeons. With the availability of robotic assistance, more surgeons at more institutions will be able to perform these procedures.

3. Make new surgical procedures possible: A number of procedures that are currently not feasible by minimally invasive techniques may eventually be preformed through small incisions with the help of robotic technology.

Current clinical applicability

In the United States, Intuitive Surgical, Inc. has received clearance from the FDA for use of the da Vinci™ Surgical System in laparoscopic surgical procedures such as cholecystectomy and Nissen Fundoplication and general non-cardiac thoracoscopic surgical procedures such as internal mammary artery mobilization. In addition, New York Presbyterian surgeons are involved in several FDA-sanctioned clinical trials to assess the da Vinci Robotic System for mitral valve repair, coronary artery bypass and ASD (atrial septal defect) closure.

The New York Presbyterian Robotic Cardiac Surgery Program

New York Presbyterian has two Da Vinci robotic systems - one at the Columbia-Presbyterian campus, and one at the Weill-Cornell campus. The Columbia program is directed by Michael Argenziano, M.D., and the Weill-Cornell program by Charles Mack, M.D.

Thoracoscopic Internal Mammary Artery Harvesting. The Columbia-Presbyterian team has performed over 30 internal mammary artery (IMA) harvests with the Da Vinci system, serves as an IMA harvesting training site, and has utilized Da Vinci for several minimally invasive direct coronary artery bypasses (MIDCAB), in which a bypass is performed on the beating heart, through a 2 to 3 inch incision on the left side of the chest. The Weill-Cornell team has performed over 20 IMA harvests.

Mitral Valve Surgery. The Columbia-Presbyterian team is one of nine centers in the FDA-sanctioned robotic mitral valve repair trial. Dr. Craig R. Smith, Jr. serves as the site principal investigator, and leads a team that has performed 7 such procedures to date.

Atrial Septal Defect Repair. Dr. Argenziano is the principal investigator of the single-center robotic ASD trial, and with Dr. Mehmet C. Oz, performed the first totally endoscopic open-heart operation in the U.S. on July 24, 2001. The Columbia-Presbyterian team currently has the world's largest experience with this operation (10 procedures performed), and serves as the training site for the multicenter robotic ASD trial.

Coronary Artery Bypass. Dr. Argenziano is the principal investigator of the FDA multicenter totally endoscopic coronary artery bypass (TECAB) trial, and with Dr. Smith, performed the first totally endoscopic (closed chest) coronary bypass operation in U.S. history on January 15, 2002. The Columbia team will train other centers that will participate in the trial. Dr. Mack and the Weill-Cornell team will also participate in the TECAB trial.

Arrhythmia Ablation. The New-York Presbyterian team has perfomed over 100 left atrial isolation procedures for atrial fibrillation, using a variety of energy sources. Recently, Drs. Argenziano, Oz and Williams have developed a totally endoscopic, robotic operation for atrial fibrillation. The Columbia-Presbyterian team will perform the world's first totally endoscopic human cases in the spring of 2002.

The significance of robotically assisted minimally invasive cardiac surgery

The potential significance of robotic technology in the practice of cardiac surgery is great. Cardiovascular disease remains the top killer of Americans, and over 750,000 cardiac surgical procedures are performed in the U.S. each year. The annual cost of this care, including hospital costs, treatment of complications and disability, and lost productivity and quality of life, has been estimated at several billions of dollars. Despite efforts to curb these expenditures, the costs of medical care, and especially of surgical procedures, continue to increase. Despite improved diagnostics and medical treatments over the last decade, the incidence of cardiac disease, cardiac surgery, and death due to cardiovascular causes has continued to increase. A potential explanation for continued increases in cardiovascular disease, procedures, and costs may be the changing demographics of the population. The nation is getting older, and it is estimated that by the year 2050, nearly a third of the U.S. population will be over 65 years of age. Older patients present with more complex cardiac disease, suffer higher complication rates, and thus may benefit most from less traumatic, minimally invasive approaches, with decreased recovery times and hospital costs. For these reasons, the development of reliable minimally invasive cardiac surgical procedures can be expected to make a significant impact on the quality of medical care as well as the economics of health care delivery, resulting in increased access to care, especially for elderly patients.

Despite the enthusiasm generated by our early experience with robotics in cardiac surgery, we realize that we still have much to accomplish. The technology we have available today is just an initial iteration of what is sure to be a complex developmental process. The continued evolution of robotic technology, toward the goal of widespread applicability, will require many mechanical and engineering refinements. However, as important to the eventual success of this technology will be the development of adjunctive technology, such as facilitated anastomotic devices, endoscopic retractors and stabilizers, and cardiovascular support devices. Robots have given us a previously unimaginable degree of thoracoscopic visualization and instrument dexterity - the next step is to develop facilitating technology to fully utilize this newfound access to the heart.