Understanding the Difference Between Electrosurgery and Electrocautery

In the medical field, there is often confusion between the terms "electrosurgical generators" and "electrocautery." It's important to recognize the distinctions between these technologies to ensure accurate communication and understanding among medical professionals.

Electrocautery: An Overview

• Historical Use: Electrocautery, an old technology dating back to the 18th century, involves the application of DC (direct) current through a metal element to create cutting and coagulation by burning and destroying tissue through heat transfer.
• Basis of Effect: The primary mechanism of electrocautery is the heating of the pen head, which then transfers heat to the tissue, leading to tissue destruction.

Electrosurgery: A Modern Advancement

• Origins: The theory of using high frequency in electrocautery was proposed by William T Bovie around 1920, ultimately leading to the development of electrosurgery devices.
• Technology: Electrosurgery devices apply high-frequency AC (alternating) current directly to the tissue, resulting in high frequency thermal effects for tissue cutting and coagulation.
• Enhanced Capabilities: Electrosurgery offers several advantages over electrocautery, including easier tissue cutting without tissue sticking to the electrode and the ability to modulate the current waveform for a selectable spectrum between cutting and coagulation.

Advantages of Electrosurgery Over Electrocautery

• Efficiency: Electrosurgery offers enhanced capabilities and efficiency compared to electrocautery.
• Tissue Management: It enables easy tissue cutting without tissue adherence to the electrode, improving surgical precision.
• Modulation: Surgeons can adjust the waveform of the current applied to the tissue, allowing for a selectable spectrum between cutting and coagulation.

Electrosurgery, also referred to as electrical surgery, harnesses the thermal effects of high-frequency electric currents to enable surgical procedures by achieving hemostasis, i.e., stopping bleeding. This approach offers several advantages over traditional mechanical surgery, including efficient hemostasis, rapid recovery, reduced infection risk, and protection of tissues from mechanical trauma. Notably, electrosurgery is adaptable for use in remote anatomical areas such as the digestive system and urinary tract.

Living tissues, characterized by significant electrical conductivity, readily permit the passage of electric current. The biological effects of electric current in the human body encompass electrolytic effects, faradic effects, and thermal effects. Electrosurgical devices are designed to operate at frequencies that render the electrolytic and faradic effects negligible, with the thermal effect being the primary influence on biological tissues.

Electrolytic Effects:

The flow of electric current through tissues causes the separation and accumulation of ions around the positive and negative poles. This ion accumulation can potentially lead to cellular destruction. However, at high frequencies, the ions within the tissues do not move toward the poles, mitigating the electrolytic effect.

Figure 1 - Electrolytic effects of direct current and accumulation of ions around the poles

Figure 2 - Avoidance of electrolytic effect by using high frequency current

Faradic Effects:

The faradic effect refers to the stimulation of sensitive nerve and muscle cells by electric current. This stimulation can result in muscle spasms and discomfort, and at higher levels, it can lead to irregular heart contractions. The impact of the faradic effect increases from zero to 100 Hz and diminishes continuously thereafter. Given that the minimum time required to stimulate sensory or motor nerves is approximately 5 microseconds, at a frequency of 100 kHz, the faradic effects are minimal. Furthermore, at frequencies exceeding 300 kHz, these effects can be disregarded. Therefore, electrosurgical techniques typically utilize frequencies higher than 300 kHz.

Figure 3 - Effects of electrical stimulation on nerves and muscles (faradic effect) in terms of frequency

Thermal Effects:

Electrosurgical devices leverage the thermal effects of electric current passing through tissues to achieve precise cutting and coagulation. As the current traverses the tissues, akin to any other conductor, it generates heat energy, the quantity of which is contingent on the current magnitude, duration of exposure, and the tissue's electrical resistance.

(dissipating electric power in the tissue) P = RI2

 (Thermal energy generated in the tissue) W = P × t

The dissipation of electric power in the tissue is given by the formula P = RI^2, while the thermal energy generated in the tissue is represented by W = P × t. If the current density passing through the tissue is sufficiently high, the intracellular fluids can rapidly heat and evaporate, leading to the bursting and tearing of cell membranes due to the vapor pressure inside the cells. The resulting energy from these microscopic cell explosions is absorbed by water vapor, thereby preventing damage to adjacent tissues and facilitating tissue cutting or coagulation.

Given that electrosurgery devices operate at frequencies above 300 kHz, the ions within the tissue do not move or vibrate. Additionally, neuromuscular stimulation at these frequencies is minimal. Consequently, the electrolytic and faradic effects can be disregarded in electrosurgery, with the thermal effects of current passing through the tissue being the predominant phenomenon.

In summary, electrosurgery leverages high-frequency electric currents to primarily induce thermal effects on biological tissues, offering a precise and effective method for surgical hemostasis and tissue manipulation.

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In monopolar electrosurgery, the current that penetrates the patient's body through the monopolar pen electrode returns to the device through the plate, also known as the neutral electrode. Correct usage and appropriate placement of the plate are crucial for ensuring the effective and safe use of monopolar electrosurgery. Plates are available in different types, including one-piece and two-piece designs.

1. Consider Dual-pad Plates for Enhanced Safety
• To enhance patient safety, it is advisable to utilize double plates. The use of two-piece plates significantly reduces the risk of unintended burns at the site of the plate. When using one-piece plates, the device cannot control the quality of contact between the plate and the patient.
2. Prevent Increased Current Density
• A reduced contact surface of the neutral electrode or its inadequate connection with the patient's body can elevate the current density, potentially resulting in burns at the contact site. Kavandish System's devices are equipped with a system to monitor the status of the patient's plate, ensuring patient safety and mitigating burns caused by improper plate-to-patient connection. If there is an issue with the contact quality of the double plate with the patient's body, the device detects it and triggers an alarm.
3. Optimal Placement of the Plate
• The entire flat side of the current conductor from the plate should be securely affixed in a suitable location where normal blood circulation is possible, such as the upper arm or upper thigh, closest to the surgical site. This minimizes the current path between the monopolar active electrode and the plate, avoiding the passage of current through the heart and lungs.

Suggested plate attachment locations according to the surgical site

4. Ensure Adequate Contact Surface

• Place the plate to establish a substantial contact surface with the patient's skin. Insufficient contact may lead to increased current density in the contact area, potentially resulting in burns.

Reduction in efficient contact surface between the patient and the plate

Electric current conducting area

An area that does not conduct electric current, because it does not have contact with the skin, or because it is oxidized or contaminated with fat particles, resulting in very weak conduction.

5. Enhance Skin Conductivity

• Increase the electrical conductivity of the skin in the area where the neutral electrode is positioned by cleaning, massaging to improve blood flow, and shaving the hair from the contact area.
1. Mindful Placement
• Avoid situating the plate over large blood vessels, bones, or areas with poor blood circulation.
2. Plate Maintenance
• Adhere to the manufacturer's guidelines and ensure the patient's plate remains unaltered, free from tears or cuts.

1. Cable Insulation
• Regularly inspect the insulation of the cable connected to the neutral electrode for any damage.
2. Patient Mobility
• Upon moving the patient, verify the correct connection of the plate.
3. Consider Implants
• If the patient has conductive implants, position the plate to avoid current flow through these areas.
4. Pacemaker and Electronic Devices
• In cases where the patient has a pacemaker or other implanted electronic devices, take precautions to minimize interference, such as consulting a cardiologist, using reliable monitoring equipment, and ensuring the availability of an electroshock device.
5. Polymer Plate Usage
• When using polymer plates, ensure the use of silicone and standard types to prevent burns. Worn or old polymer plates may deteriorate in quality over time.
6. Permanent Plates
• Apply suitable gel uniformly on the entire surface of permanent plates, secure the plate's position using rubber bands to maintain good contact with the patient's skin.
7. Moisture Prevention
• During the operation, prevent fluids or moisture from reaching the contact area of the plate, as these can increase the risk of burns.
8. Avoid Improper Methods
• Refrain from using water, saltwater solutions, or wet cloths to improve the plate's contact with the patient.