History of Plasma Electrosurgery

Hemostasis, the controlling of blood loss and tissue destruction are of critical importance when removing abnormal tissue during surgery. Arresting blood loss is of high priority during surgery so as to avoid or minimize the necessity of introducing foreign blood or blood products into a patient. Minimizing blood loss has increased in importance due to concern over contamination of the blood supply by viral agents that cause, for example, acquired immune deficiency syndrome (AIDS), hepatitis and the like.

Electrosurgery Principles – For over 5,000 years the utilization of heat and fire has been the crude method of hemostasis. One of the first applications of electrocautery was the heating of an iron with fire and then applying to a wound to order to control bleeding. In 1875 several inventors developed an electric current which passed through wire loops until significant amounts of heat was generated through the wire loops and the heat was subsequently transferred to the tissues by direct contact with the hot wire. The vacuum tube was later developed in the twentieth century and used as an electrical device. These applications of electrocautery were cautery devices but were not true electrosurgery. In electrosurgery, heat is transferred to tissue from a preheated object and the currents heat only the electrode and they do not pass through the patient’s body. The method of electrosurgery involves the cutting and coagulation of tissue by transmitting a highfrequency current through the target tissue.

In 1920 William Bovie, PhD, professor of electrical engineering at Massachusetts Institute of Technology, was the first to describe the technology of electrosurgery. In 1928 Dr. Harvey Cushing (Chief of Surgery at Brigham/Women’s hospital) and Dr. Bovie were the first to use the electrosurgery technology in the clinical arena at Brigham/Women’s hospital in Boston, Massachusetts. Presently, the standard means for controlling traumatic and surgical blood loss are electrosurgical generators and lasers, which respectively direct high-frequency electrical currents or light energy to localize heat in bleeding vessels so as to coagulate the overlying blood and vessel walls. Since the famous report by Bovie and Cushing, Bovie’s name has been synonymous with electrosurgical units (ESU). The ESU developed by Bovie, was a spark-gap unit, which consisted of two small metal conducting pieces separated by an air gap. The mechanism is similar to an automobile spark plug.

The concept of lasers was first described in Einstein’s published papers on quantum theory in 1917. In 1960 Maiman developed the first laser device. From 1928 to 1970, surgeons have widely used high-frequency electrosurgery for hemostasis, coagulation and tissue heating. During the 1970’s fiber-optic flexible endoscopes were developed to visualize the esophagus, stomach, duodenum and colon. In 1970, Blackwood and Silvis postulated that endoscopic electrosurgery was possible. Flexible electrical devices were subsequently invented for flexible endoscopes. The three modes of high-frequency coagulation are monopolar, bipolar and fulguration. Monopolar and bipolar are the two primary modes of high-frequency energy used today.

Plasma Technology: The application of plasma technology in industry is currently a trillion dollar business worldwide with applications in such things as televisions, cars, lighting, etc. Recent advances in physics, chemistry and materials science have led to the development of a variety of new advanced technologies and applications. Plasma utilized in medical surgical devices is the result of these technological advancements.

What is Plasma? Plasma is not a human invention. The word plasma is derived from the Greek language “to form” or “shape”. Plasma events are found in the stars, sun, tails of comets, flashes of lights and northern lights.

Plasma is the fourth state of matter. Matter can be configured as solid, liquid, gaseous, or plasma states. By gradual increases in temperature, ice (solid state) can be converted into water (liquid state), water into steam (gaseous state) and steam into plasma (plasma state). Electrical conduction of the gas occurs when additional energy is supplied to the gas, despite the preservation of electrical neutrality. This process occurs when the electrons gain sufficient energy to separate from the atoms or molecules of the gas. Plasma is a collection of electrically charged particles such as electrons and non-charged particles such as radicals (a type of chemically reactive atom or molecule). Plasmas are functionally different if they are in thermal equilibrium as opposed to nonequilibrium states. Thermal equilibrium plasmas are typically present in stars; in contrast to nonequilibrium plasmas that do not produce heat overload (low temperature plasmas). Low temperature plasmas (Cold Plasma) are ubiquitous throughout our daily lives; this technology is indispensable in modern material science, microelectronics, nano-technology, and semiconductor technology. Cold Plasma technology has remarkable and vast biomedical applications. It is believed that Cold Plasma technology will replace conventional modes of medical treatment in surgery and medicine.

For 50 years there was no major advancement in high-frequency electrical energy until 1977 when Morrison described an electrosurgical method and apparatus for coagulating by fulguration where an electrical discharge is established through an inert gas. In 1986 McGreevy described a similar electrosurgical technique with an inert gas. The Argon Beam Coagulator (ABC) or Argon Plasma Coagulator (APC) was subsequently developed by Bard Electro Medical Systems, Inc. Boulder, Colorado for clinical use. The technology skyrocketed in the surgical arena. In 1989, Birtcher Medical Technology (BMT) acquired the technology from Bard and in 1994 CONMED (Utica, NY) acquired BMT’s intellectual property.

The APC has been shown to be effective in coagulation of blood vessels and human tissue during surgery. It is a form of cold plasma technology. APC technology is superior to conventional modes of electrosurgery (RF radio frequency) because tissue destruction is greatly reduced.

The APC is based on the use of a beam of high purity (99.999% pure) ionized argon gas to conduct the current to the tissue. A stream of argon is colorless, odorless, inert (inactive) gas that conducts the current to the tissue and vessel walls. Argon is a noble, inert gas that will not react with other elements. It is one of the safest gases known. It will not support combustion and it clears the body in one respiratory cycle. The APC functions in a non-contact manner. The electrical current is initiated only when the tip of the hand piece or catheter is within 1 cm. of the target tissue. A more homogenous 1 to 2mm well delineated eschar is produced by the APC which is more effective than standard electrocautery because it disturbs the arc tunnels in a more even pattern and more uniform depth to the target tissue. The eschar remains firmly attached to the tissue, in contrast to other modalities of coagulation where there is an overlying charred layer of coagulated blood. Argon gas is used in this system because it will not oxidize the electrode. The temperature in the tissue being cauterized never exceeds 110˚ because of the cooling effect of argon gas and because no further conduction of radio frequency energy into tissue occurs once an eschar forms. This process is thought to minimize tissue destruction and necrosis.

In contrast to the APC, electrosurgery and lasers use electrical current or light energy to localize heat and thereby achieve hemostasis. With temperature dependent mechanisms such as eletrocautery, tissue temperature increases to 200˚, causing the heating of cellular water to boiling and the subsequent rupture of cell membranes and the photo evaporation of tissue. With lasers, tissue temperature rises even higher to 300˚ to 400˚ at which point carbonization occurs and then to 500˚ when combustion occurs. This heat is distributed in an uneven fashion and may lead to the damage of adjacent tissue and an unknown depth of tissue injury.

A standard APC probe includes a flexible wire having a nozzle tip with an opening through which argon gas flows. The device includes a handle for placing the tip in position for tissue coagulation. Within the tip is located a tungsten needle for discharging radio frequency (RF) current which ionizes the argon gas.

Utilization of argon gas technology had been limited to use for open surgery and rigid laparoscopes until Dr. Canady’s invention in 1993. USMI will be first to introduce Microplasma Cutting technology in surgery.

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