Frequency and waveform
The operating frequency of medical radio frequency grade high-frequency electrosurgical devices is 1.5MHz-6.0MHz, while the operating frequency of commonly used ordinary high-frequency electrosurgical devices is 450KHz-650KHz.
Working principle
The working principle of ordinary high-frequency electrosurgery is Ohm's law. When an electric current passes through human tissue, heat is generated due to the resistance of the tissue. When the current remains constant, the greater the impedance, the greater the heat. When ordinary high-frequency electrosurgery works, current passes through the electrode. The smaller the contact area between the electrode and the human body, the greater the impedance, and the greater the heat at the contact location. The cells are heated and burst (similar to a balloon being scalded), thereby achieving cutting or Purpose of stopping bleeding. Because the current of ordinary high-frequency electrosurgery flows out from the electrode, flows through the human body, and then flows back to the host from the negative plate to form a path. There are two key points here: first, there must be a negative plate, and the area must be large enough, and it must be in good contact with the human body. Otherwise, the contact area is small, the impedance is large, and burns will occur; second, there is current passing through the human body.
When cutting with ordinary high-frequency electrosurgery, a certain amount of mechanical force needs to be applied, which can easily cause a larger wound; high temperatures can cause tissue carbonization or protein denaturation, and the wound healing time will be long. Mainly used in major surgeries.
The working principle of RF-level high-frequency electrosurgery is that the working end of the electrode outputs electromagnetic waves (not current) with a very high frequency, generally higher than 1.5MHz, which are concentrated in a small area through the electrode. Since cells contain a large number of water molecules (water The molecules are polar molecules and are affected by electromagnetic waves). Under the action of this local high-frequency electromagnetic field, water molecules oscillate rapidly and hit the cell wall to rupture it, thereby achieving the purpose of cutting or stopping bleeding. Radio frequency has no current, so it does not require a negative plate, but it still requires electromagnetic waves to be formed between the neutral plate and the electrode, but the electrode plate does not need to be in direct contact with the human body. It can be placed across a sheet or clothing, or away from the surgical area.
The radiofrequency-grade high-frequency electrosurgical knife itself does not generate heat, so it is a low-temperature cutting without unnecessary tissue damage. It has small wounds, fast healing, minimal thermal damage to the side of human tissue, fine and accurate cutting, and smooth tissue surface; no current passes through the human body, so More security. Therefore, it is used in minimally invasive and delicate surgeries.
Operation methods and effects
Ordinary high-frequency electric scalpels must have a negative plate when working (the current flows through the human body, and then flows back from the negative plate to the host to form a loop), and the area is large enough to have good contact with the human body. Otherwise, high temperatures will cause tissue carbonization or protein denaturation. Comparatively Burns are prone to occur; therefore, a certain amount of mechanical force needs to be applied when cutting, which can easily lead to larger wounds and longer wound healing time. Its main application is in major surgery.
Radiofrequency-grade high-frequency electric wave knife has no current and does not require a negative plate when working. It only needs electromagnetic waves to be formed between the neutral plate and the electrode. It does not need to be in direct contact with the human body. It can be placed through clothes or sheets, and can also be placed away from the surgical area. . Low-temperature cutting at 40℃-70℃ has minimal thermal damage to the side of human tissue, causes small wounds, and has a fast healing time. Mainly used in minimally invasive and delicate surgeries.
