Prospective Clinical Trial of Robotically Assisted Endoscopic Coronary Grafting With 1-Year Follow-Up

During the past 10 years, surgeons have begun to explore strategies to decrease the invasiveness of cardiac surgery. Great strides have been made in the development of beating heart surgery, which eliminates cardiopulmonary bypass. 1 Techniques also have been developed to decrease the size of the incision, and some procedures can now be performed through small thoracotomies 2 and limited sternotomies. The next step in the evolution of minimally invasive cardiac surgery would be the development of a completely endoscopic procedure. 3 The explosion of arthroscopic and laparoscopic techniques during the past several decades has revolutionized orthopedic and general surgery. However, endoscopic techniques have had little impact on microsurgical disciples, such as cardiac surgery. There are several reasons for this shortcoming. Traditional endoscopic instruments are not well suited for microsurgery 4 because of their length and the fulcrum effect. The length of the instruments magnifies even the smallest surgical tremor, making microsurgery difficult if not impossible. The fulcrum effect makes it difficult to judge precisely the deflection of the instrument tip for a prescribed movement of the instrument handle. Moreover, the nonintuitive movement of endoscopic tools (i.e., the instrument tip moving opposite to the handle) is problematic for fine microscopic suturing. Traditional endoscopic visualization also is a hurdle to the performance of microsurgery. There is a lack of depth perception on the video image, and the hand-held endoscopic camera often yields an unsteady picture in highly magnified surgical fields. With recent advancements in computers 5 and robotic systems, it was hypothesized that robotics would prove to be an enabling technology for endoscopic cardiac surgery. 6,7 This study reports the 1-year follow-up of the first prospective, nonrandomized trial in North America of endoscopic coronary artery bypass grafting (ECABG). The Zeus Robotic Surgical System (Computer Motion, Inc., Goleta, CA) was used in this trial. This system consisted of a surgeon console (Fig. 1), a computer control system, and three robotic arms (Fig. 2). The surgeon remained seated in a chair in front of the console, which consisted of a video monitor, two instrument handles, and a computer control system. The instrument handles were identical to traditional Castro-Viejo microsurgical needle drivers. As the surgeon moved the handles, his or her motions were mechanically relayed to a computer control system and digitized. Once the software processed the digital information (tremor filtration, motion scaling), the commands were relayed in real time to the two robotic arms. These arms, attached to the operating table, precisely controlled the instrument tips, which entered the patient through 5-mm ports. A third robotic arm held the endoscopic camera and was controlled by simple voice commands. Figure 1. The Zeus Robotic Surgical System. The surgical console consists of a video monitor and two customized instrument handles. The surgeon grasps the handles and his or her movement is mechanically relayed to a computer control system, which digitizes ... Figure 2. The robotic arms are attached to the operating table and precisely control two instrument tips that are positioned within the patient through 5-mm ports. A third voice-controlled arm is used to manipulate the endoscope. Before beginning clinical studies, our group used the Zeus system to successfully complete coronary artery anastomoses in both cadaveric and live animals. 8,9 This single-center prospective clinical trial was approved by the Food & Drug Administration to evaluate the safety and efficacy of robotically assisted ECABG. All patients enrolled in this trial underwent robotically assisted anastomosis of the left internal thoracic artery (LITA) to the left anterior descending artery (LAD). All other grafts were sewn by hand in a traditional fashion. It was mandated that the procedures had to be performed on the stopped heart with cardiopulmonary bypass and cardioplegic arrest. The primary study end points were graft patency at 8 weeks and the incidence of device-related complications. The 12-month follow-up end points included major adverse cardiac events and recurrent angina.