Ultrasonic scalpel is usually composed of ultrasonic power supply, hand-held treatment head and auxiliary equipment. Through this set of system devices, electrical energy is converted into mechanical energy of ultrasonic vibration, which is output by the front end of the ultrasonic hand-held treatment head, instead of ordinary scalpels. In order to achieve the purpose of surgical treatment, it is also called ultrasonic knife or ultrasonic scalpel. Ultrasonic scalpel is widely used in surgical procedures because they are suitable for incisions in soft tissue where bleeding control and minimal thermal damage are required. Ultrasonic scalpel can also be used to complement or replace high-frequency scalpels, laser scalpels and steel scalpels, thus greatly broadening the application fields of ultrasound therapy.
The working principle of the ultrasonic scalpel is to use the electrostrictive effect or the magnetostrictive effect to convert ultrasonic energy into mechanical energy, and the knife head is pushed to work through the amplification and coupling of the horn, and the energy is radiated to the local tissue of the human body to perform surgery.
Ultrasonic scalpel is mainly composed of two parts, namely ultrasonic power supply and ultrasonic vibration system. The ultrasonic vibration system consists of three components: an ultrasonic transducer, a concentrator and a cutter head, it is the so-called ultrasonic handheld treatment head.
(1) Ultrasonic transducer is a key component for generating high-power ultrasonic waves, and its function is to convert high-frequency electrical energy into ultrasonic vibration energy. In the field of power ultrasound, the generation of sound energy is mainly through three different methods, namely the hydrodynamic method, the piezoelectric effect method and the magnetostrictive effect method.
Hydrodynamic ultrasonic generators include two types of sound sources: airflow sound sources and fluid hydrodynamic generator sound sources. A transducer that works on the basis of the piezoelectric effect is called a piezoelectric transducer. The most widely used in the field of power ultrasound is the sandwich piezoelectric transducer. Magnetostrictive transducer is a kind of machine-acoustic conversion sound-emitting device made based on the magnetostrictive effect of some ferromagnetic materials and ceramic materials. Compared with the piezoelectric ultrasonic transducer, its application range is already small, because the electromechanical conversion efficiency of the magnetostrictive transducer is low, and its excitation circuit is complicated.
(2) There are many forms of ultrasonic concentrators. The most commonly used one is ultrasonic horn, which increases the displacement amplitude or velocity amplitude of ultrasonic vibration, and can concentrate energy, that is, concentrate ultrasonic energy on a smaller area, it can also radiate ultrasonic energy to a larger area, and can also be used as a mechanical impedance converter to build a bridge between the transducer and the load for impedance matching, so that the ultrasonic energy can be more effectively transferred from the transducer to the load.
(3) The ultrasonic power source is the ultrasonic generator, which is a device used to generate and provide ultrasonic frequency electric energy to the vibrator of the ultrasonic transducer. It is usually composed of a waveform generator, a power amplifier and an impedance matching network.