Advances Towards Beating Heart Surgery
Cardiovascular disease affects many patients each year, some of whom will require surgery. The advent of minimally invasive surgery has greatly reduced the amount of trauma a patient undergoes when a surgical procedure is performed on the heart. However, current interventional practices leave much to be desired. Currently, surgeons have two options when operating on a heart: either the heart is mechanically stabilized or it is arrested and the patient is connected to a heart-lung bypass machine. In fact, due to the heart's fast motion, it is extremely difficult for a surgeon to operate on a freely beating heart. The effectiveness of mechanically stabilizing the heart is limited to areas on the outer surface of the heart that are accessible from the chest cavity. As for arresting the heart, this approach does not allow the surgeon to evaluate the outcome of the procedure intra-operatively when the heart is drained and not beating. To accurately evaluate the effectiveness of most corrective cardiac surgeries and perform further adjustments to improve the outcome, the heart must be freely and normally beating during the procedure.
A new operative technique with increased safety and effectiveness that does not require the heart to be arrested or stabilized is robot-assisted beating-heart surgery. A surgical robot (holding a surgical tool) is computer controlled to automatically follow the beating motion of the heart such that the heart appears stationary with respect to the surgical tool. A surgeon can then, through a user interface, control the surgical robot in order to operate on a seemingly stationary heart even though the heart is actually beating freely.
Beating-heart surgical systems, although designed differently for different procedures, contain common components. The two main components are a motion-capture module that will measure the position of the heart and the surgical tool and a control system that will use the information gathered by the motion-capture module to automatically make the surgical tool follow the heart's motion. The design of these two components is based on the target surgical site and procedure. For example, a fast video camera or an endoscope could capture the heart's motion for surgical procedures performed on the outside of the heart. However, a different method that can visualize through the blood pool within the heart must be used for a procedure performed inside the heart. For instance, ultrasound imaging or even a force sensor could be used for motion capture depending on the requirements of the procedure. This chapter will discuss the many different heart motion-capture modules and control systems that have been proposed as well as the advantages and disadvantages of each method. In addition, a discussion of which types of surgical procedures can benefit from a beating-heart surgical system is included.