Standard Monopolar Electrosurgical Unit:
A high-frequency electrosurgical unit (or high-frequency surgical instrument) is an electrosurgical device designed to replace mechanical scalpels for tissue cutting. It functions by generating a high-frequency, high-voltage current at the tip of an active electrode; when this tip contacts the body, it heats the tissue, thereby achieving the separation and coagulation of biological tissue to fulfill the objectives of cutting and hemostasis. It utilizes a complete electrical circuit to cut and coagulate tissue; this circuit consists of a high-frequency generator housed within the unit, a patient return electrode (grounding pad), connecting cables, and the active electrode.
Simplified Diagram of Electrosurgical Unit Operation
In most applications, the current flows from the active cable and electrode through the patient's body, and then returns to the electrosurgical generator via the patient return electrode and its connecting cable.
Usage Tips:
· Do not set the power level too high. Actual energy output varies between different instruments, or even within the same unit, depending on its specific operating mode. Generally, power settings for electrosurgery (cutting) and electrocoagulation should not exceed 40 watts. The guiding principle is: set the power to the minimum level required to successfully complete the procedure. However, during cytoreductive surgery for ovarian cancer-specifically when addressing hepatic metastases-the electrocoagulation setting may typically be increased to 100 watts to ensure effective hemostasis within the liver tissue.
· An electrosurgical electrode is not a conventional scalpel. The principle of electrosurgical cutting relies on the incision created by electrical sparks resulting from intermittent discharge; therefore, the electrode should not be treated or used like a standard blade. Maintain a slight gap between the electrode and the tissue, allowing for the generation of uniform, small sparks. Do not press the electrode forcefully against the tissue, as this can result in tissue crush injury.
· Tissue traction is crucial. It is essential to lift the skin flap at a 45-degree angle to create a distinct working space or plane within the tissue layers. The electrode should be guided through this created space to ensure clear visualization and dissection along anatomical planes.
· Control the speed of electrode movement. Moving too slowly can cause excessive tissue damage; moving too quickly risks damaging critical anatomical structures.
· Use electrocoagulation for hemostasis. Generally, utilizing a hemostatic forceps to grasp and lift the vessel-and then applying the electrode to the forceps-yields superior hemostatic results.
· In patients with thick subcutaneous adipose tissue, minimize the use of the electrosurgical unit to avoid tissue liquefaction and necrosis, which can impede wound healing.
· Since the electrosurgical unit exerts its primary effect at the point of highest electrical resistance (typically the contact point), it is critical to ensure a reliable connection between the patient return electrode (grounding pad) and the skin. The contact area should be as large as possible to prevent burns! · Do not attempt to cut into an excised specimen; since no electrical circuit is formed, the device will not react. If a reaction *does* occur, it means the current is flowing through the surgeon themselves-at which point the surgeon will receive an electric shock!
· For areas rich in muscle tissue-should it be necessary to transect the muscle-using the electrocoagulation mode will result in less bleeding. This is because electrocoagulation cuts more slowly and utilizes a lower current, allowing sufficient time for the muscle tissue to "char" and achieve hemostasis. However, when a large volume of tissue is clamped and electrocoagulation proves insufficient to stop the bleeding, switching to the electrocautery (cutting) mode will yield excellent hemostatic results.
· When using an electrosurgical knife in deep tissues, whenever possible, opt for a long-handled instrument with only the very tip of the blade exposed; this prevents the exposed metal shaft from inadvertently damaging adjacent structures, such as blood vessels or nerves.
· Exercise caution to avoid accidental injury to the epidermis with the electrosurgical knife. Ideally, the subcutaneous tissue should not be incised using the electrosurgical knife; instead, use a conventional scalpel to open the subcutaneous layer, followed by spot electrocoagulation to achieve hemostasis. In anatomical regions where bleeding is not expected to be profuse, the electrosurgical knife may be dispensed with entirely in favor of surgical scissors or a conventional scalpel.
· When removing internal fixation hardware, ensure the electrosurgical knife does not come into contact with the implants themselves. This is particularly critical during spinal surgery; accidental contact between an energized electrosurgical knife and spinal fixation hardware can damage the dura mater, nerve roots, or spinal cord-potentially resulting in neurological injury or even paraplegia.
· **Important Precaution:** Monopolar electrosurgery should *not* be used to directly coagulate or transect the blood vessels of the uterus or ovaries, as this carries a high risk of hemorrhage. Should bleeding occur, the resulting obscured anatomical field increases the likelihood of inadvertent injury to adjacent structures, such as the ureters, bladder, or intestines. Instead, the blood vessels of the uterus and ovaries should be managed using bipolar electrocoagulation or conventional suture ligation techniques.