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The use of heat to stop bleeding or achieve other medical goals has a long history, dating back to Albucasis in 980 BC, who described a hot iron like electrocautery to control bleeding in patients. In the 19th century, a French surgeon named Arsene d'Arsonval discovered that frequencies above 10 kHz merely generate heat in biological tissues and do not cause neuromuscular stimulation. Later, Oudin revealed how a device based on this notion was successfully used to destroy living tissues. In the twentieth century, the partnership of a famous neurosurgeon Harvey Cushing and a Harvard physicist William Bovie culminated in the invention of contemporary electrosurgical equipment that can cut, desiccate, and coagulate.
Since then, numerous technology breakthroughs and design modifications have been produced and widely used in various surgical sectors to lower the risk of problems.
Electrosurgery Basic Principles
The product of current and voltage is energy in watts (power). Power is defined as the product of current and voltage at a particular place, expressed in wattage or watts (W). W=VI relates to the pace at which work is completed.
Ohm's law shows the relationship between the qualities of electrosurgical energy, I=V/R.
Current (I) is the flow of electricity via a wire or conductor, similar to how water runs down a river. On the surface of a conductor, current flows from negative to positive. Amperes (A) or amps are the units of measurement for current.
The difference in electrical potential between two locations in a circuit is known as voltage (V). It is the force that pushes current through a circuit, and it is measured in volts (V).
The amount of current that flows through a component is determined by its resistance. Resistors control voltage and current levels. Only a limited quantity of current can pass through an extremely high resistance. A low resistance permits a lot of current to pass through it. The unit of resistance is ohms.
What is Electrosurgery?
Electrosurgery is a method that generates heat by passing an electric current through the skin at varying voltages (200 to 10,000 V). It can control bleeding or eliminate abnormal skin growths (hemostasis). For Electrosurgery, a power supply and a handpiece with one or more electrodes are required.
Electrosurgery includes numerous techniques that employ electricity to cause thermal tissue damage by dehydration, coagulation, or vaporization. The two most prevalent methods of Electrosurgery are high-frequency Electrosurgery and electrocautery.
What is an ESU?
ESU stands for Electrosurgical units. A generator and a handpiece with one or more electrodes make up an electrosurgical unit (ESU). The device is controlled by a footswitch or a switch on the handpiece. Electrosurgical generators can generate electrical waveforms in a variety of ways. The related tissue effects alter as these waveforms change. ESUs in operating rooms transform conventional electrical frequencies (50 to 60 Hz) from wall outlets to much higher frequencies (500,000 to 3,000,000 Hz). This is necessary to avoid nerve and muscle stimulation at electrical currents lower than 10,000 Hz. When electrical current is applied to tissue, it can cause fulguration, desiccation/coagulation, or vaporization/ablation.
Differences That Matter
Let's take a closer look at these methods to see how they differ in terms of therapeutic application and tools used.
Electrosurgery works by passing electrical current into the tissue to achieve a specific outcome. The electricity used is an alternating current similar to that which is used to create radio waves. The average frequency is fairly high, with 500,000 cycles per second being the standard. This ensures that the current travels through the tissue of the patient rather than causing an electric shock.
The tissue's resistance to the electrical current generates heat, and the electrodes used to administer the current include blades, round balls, needles, and loop shapes. The desired outcome determines the electrode choice. These devices are capable of cutting, coagulating, and even fusing tissue.
Two types are most prevalent- Bipolar Electrosurgery and Monopolar Electrosurgery:
Bipolar Electrosurgery
Both the active electrode and the return electrode activities are performed at the operation site in bipolar Electrosurgery. The forceps' two tips perform the operational and return electrode activities. The electrical circuit only includes the tissue grabbed by the forceps. There is no requirement for a patient return electrode because the return function is performed by one forceps tip. Bipolar Electrosurgery works in any media, allowing for coagulation in a fluid environment - a significant advantage when attempting to coagulate in a wet field. Bipolar Electrosurgery is commonly referred to as 'wet field' cautery as a result of this. Laparoscopic operations have recently been transformed by bipolar and ultrasonic hemostatic vascular sealing devices with simultaneous cutting capabilities. ENSEAL G2 Tissue Sealers, a new generation of advanced bipolar devices patented by ETHICON (Ethicon Endo-Surgery Inc., Cincinnati, OH), have been designed to improve cutting precision, reduce thermal injury using temperature-regulating jaws, and finally provide a more cost-effective alternative in the field of minimally invasive surgery.
Monopolar Electrosurgery
The active electrode in monopolar Electrosurgery is positioned at the operative site. The patient return electrode (also known as a 'dispersive pad') is attached to the patient's body in another location. As the current completes the circuit from the active electrode to the patient return electrode, it flows through the patient. The patient return electrode's job is to withdraw current from the patient safely. If the heat generated overtime is not safely dispersed by the size or conductivity of the patient return electrode, a return electrode burn will result. Modern electrosurgical equipment contains built-in safety mechanisms to prevent burns caused by poor contact between the patient and the return electrode when using the monopolar mode.
What is Electrocautery?
Electrocautery, also known as thermocautery, is a type of Electrosurgery that does not involve the use of electricity. As a result, it can be utilized safely in patients who have cardiac pacemakers, implantable cardioverter-defibrillators, or deep-brain stimulators installed.
Electrocautery involves using an electrical current to heat a metal wire, which is subsequently applied to the target tissue to burn or coagulate it. It is not utilized to pass current through tissue but rather to directly use it to the treatment area. Heat is transferred through a resistive metal wire that serves as an electrode in this approach. This hot electrode is then put directly on the treatment location, causing the tissue to be destroyed.
The word "electrocautery" is frequently used mistakenly to denote Electrosurgery.
Even among many specialists working in numerous healthcare disciplines, the phrases Electrosurgery and electrocautery are frequently misunderstood. Even though both of these treatments are employed in various medical disciplines, the tools used and the manner of application is incredibly different.
What are the potential dangers of Electrosurgery?
The dangers of Electrosurgery might harm both the patient and the healthcare provider.
Electric shock:
It can be reduced by earthing various electrodes together. To avoid an electric shock, the surgeon should wear plastic surgical gloves.
Electric/thermal burns:
If combustible elements such as alcohol, oxygen, or bowel gases are present at the treatment site, Electrosurgery poses a risk of fire or explosion.
Using non flammable cleansers like chlorhexidine or povidone-iodine ensures that the individual being treated is not in contact with metal items and ensures that the electrode is not put over a bony prominence, scar tissue, or implanted metal can all help to reduce burns.
Infection can spread through the treatment electrode, surgical smoke, and aerosolized blood microdroplets, resulting in the formation of hazardous gases. If inhaled, aerosolized blood droplets can travel up to 30 cm and are contagious. During the process, surgical smoke might spread viruses and bacteria. Hazardous chemicals and cancer-causing compounds are also carried by the smoke (carcinogens). A smoke-evacuation system and facial masks, protective glasses, and medical gloves can help reduce the risk of infection. Disposable or sanitized electrodes also aid in the prevention of infection spread.
Malfunction of cardiac pacemakers and defibrillators:
The passage of electric current through the patient's body poses a danger of implanted cardiac devices malfunctioning.
Efforts to solve the existing issues in Electrosurgery
Various engineering advances have been created over the last several decades to solve the usual difficulties that occur during electrosurgical operations. Before 1970, the most prevalent issues were ground point, alternative, and dispersive electrode burns. Ground site burns caused by ground-referenced generators and potential contact with a pass to ground were a common complication of Electrosurgery during that time, but that has since changed with the development of ground isolated systems.
Furthermore, a return electrode monitoring system could be employed to deactivate the device if the contact between the dispersive pad and the patient's body is disrupted, preventing electrical burns at the dispersive pad site.
The use of disposable tools and careful maintenance of electrosurgical devices could drastically reduce unintentional burns caused by insulation failure. Furthermore, active electrode monitoring could detect stray energy and shut down the generator in the event of capacitive coupling and insulation failure, which might be invisible to experienced surgeons' naked eyes; thus, preventing deleterious outcomes due to high concentrations of currents was done unintentionally through small defects.
Patent Data Analysis - Electrosurgery
Top 10 Countries
The US leads the countries in the count of patents with an astonishing 2626 patent applications. European countries stand at the second spot with a bounty of 1504 patents. Japan secured fourth place with 970 patents followed by Germany with 718.
Top 10 Companies
Covidien is the king for companies with the highest number of patents in the Electrosurgery sector, i.e., 1,494. The University of Texas holds the second position, while Ethicon is third.
Patent Filing Trend Over Last 10 Years
The first year records a bang opening with 504 patents, with a marginal increase in the third year with 714 patent applications. In the last two years patent application filing in the field of electrosurgery has fallen down which shows that technology has reached to its stable state.
The Bottom Line
Electrosurgery is defined as the use of a high-frequency electrical current to tissue to achieve a desired clinical result.
The whole operating room crew must have a complete understanding of the foundations of Electrosurgery in order to keep patients safe and recognize potential complications. Complications can be reduced with the use of newer hemostatic technology. Clinicians should be conversant with the basic concepts of electrosurgical equipment and techniques due to their widespread use in many surgical procedures and their clinical and cost-effectiveness. As a result, surgeons must have sufficient knowledge of the potential consequences of Electrosurgery and understand the technical flaws of regularly used tools. The widespread use of Electrosurgery in gynaecological procedures such as laparoscopy, hysteroscopy, and loop treatments emphasizes the need for more comprehensive training in this discipline. However, in the field of reproductive surgery, there is still a knowledge gap and a lack of organized training.
While using a particular modality, keep in mind the benefits and drawbacks of various types of Electrosurgery. When possible, newer technologies with better hemostatic qualities should be adopted.
References-
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3407433/
https://www.sheffield.ac.uk/polopoly_fs/1.43796!/file/Electrosurgery-for-Tonsillectomy-IPP.pdf
https://en.wikipedia.org/wiki/Electrosurgery
https://www.cehjournal.org/article/electrosurgical-units-how-they-work-and-how-to-use-them-safely/
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