The working principles of common high-frequency electrotome and radio-frequency electrotome are different, which leads to their different working environments. The working principle of high frequency electrotome is ohm's law. When current passes through human tissues, heat will be generated due to the impedance of the tissues. When the current is constant, the greater the impedance, the greater the heat. Cells are broken by heat to achieve the purpose of ablation. Radio frequency electrotome (for example, Greelembo's product frequency is 4MHz), its working principle is that the working end of the electrode outputs high-frequency electromagnetic waves, which are concentrated in a small area. Because there are a large number of water molecules in cells (water molecules are polar molecules, which are affected by electromagnetic fields), under the action of this local high-frequency electromagnetic field, water molecules oscillate rapidly and rub against each other, leading to evaporation, vaporization, tissue drying, shrinkage and aseptic necrosis in cells, thus realizing ablation. When the intervertebral foramen mirror works, it is necessary to clean the lens with normal saline to ensure the clarity of the intervertebral foramen mirror. Physiological saline is a sodium chloride solution, which contains sodium ions and chloride ions, and is a conductive solution. When the high-frequency electrotome works under the intervertebral foramen mirror, washing with normal saline will cause short circuit, reduce impedance and lose its effectiveness. The RF-level electrosurgical unit outputs RF through the electrode of high-frequency endoscopic surgery, and the working end of the electrode has two poles to form a closed loop, which can work in liquid environment and ensure safety.