1. Introduction
1.1 Background and History
Today’s technological world largely revolves around energy and its myriad of uses and implementations. Surgery is no exception and has followed this upsurge in knowledge and equipment. The vast majority of surgical procedures performed throughout the world involve the use of some device that applies energy to the tissue for cutting, coagulation, desiccation, or fulguration for the destruction or manipulation of the tissue. Whereas various energy sources, including electricity, ultrasound, laser, argon gas, microwaves, or radiofrequency (RF) waves, may be used, the fundamental principle involves tissue necrosis and hemostasis by heating. The process of denaturation of tissue begins with the irreversible aggregation of macromolecules and the unraveling of collagen helices around 60 C. Protein denaturation occurs between 70 and 80 C resulting in coagulation. Further heating to 90 C results in dehydration or desiccation. Beyond 100 C, the intercellular water boils, eventually vaporizing the cell allowing tissue cutting [1, 2]. Finally, tissue fulguration or carbonization occurs beyond 200 C. This whole process of using energy to perform tissue dissections and procedures is known as electrosurgery.
The history of electrosurgery began approximately 5000 years ago when the early Egyptians used cauterization to treat tumors. The method of electrosurgery known in modern ages though, was developed by Dr. William T. Bovie in the 1920s, where a spark gap generator was used to build the first electrosurgery tool, commonly known as RF knife or ‘‘Bovie’’ [3]. In the 1950s, the first bipolar unit was built by Dr. Leonard Malis, wherein two electrodes were used for gripping and manipulating the tissue. ...
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...eturn electrodes are located in the same tool and the electrical circuit is closed by the small area of tissues that are grasped or manipulated by the tool. Thus, bipolar tools usually are designed as grippers or forceps. Because the current only has to travel short distances in bipolar surgery, the voltage required for the surgery is low. Lower voltage is better for uniform drying of the tissue, which minimizes the chance of rebleeding. Thus, the bipolar devices are more suitable for coagulation rather than cutting. The RF energy is applied through specialized electrosurgical generators, which are RF wave form generators with different duty cycles. Different tissue effects, such as cutting and coagulation, can be achieved by selecting different duty cycles with 100 % duty cycle enables cutting, whereas lower duty cycles can be effectively used for coagulation [2].