ABSTRACT
The need to achieve hemostasis in surgery has been a concern of physicians since at least the days of ancient Egypt.1 Since that time, various forms of cautery (to destroy tissue by passively burning or searing it with a heated tool) have long been used. The earliest known use of cautery described how the physician Imhotep treated medical cases in about 3000 BC. In the last 100 years, investigators have harnessed several energy sources in a way that results in cutting or coagulating tissue as part of a surgical procedure. These include radiofrequency (RF) electricity, lasers, microwave energy, and, more recently, instruments that oscillate at ultrasonic frequencies. Most of this chapter will be dedicated to the science, tissue effects, and control and safety of RF energy; and the rest will be spent on understanding ultrasonic instrumentation.
