What is a low-intensity pulsed ultrasound therapy device?
Low Intensity Pulsed Ultrasound (LIPUS) is used for fracture treatment, orthodontic treatment that induces tooth root resorption, regeneration of missing teeth, promotion of mandibular growth in children with hemifacial dwarfism, and cartilage and soft tissue regeneration in patients with spinal disc disease. It is a medical device used in various areas, including the treatment of torn muscles.
Research on the therapeutic effects of LIPUS has been actively conducted both overseas and domestically since the late 1990s, and many studies have proven its effectiveness in cartilage regeneration and fracture healing, shortening the patient's fracture healing period. The LIPUS device has been approved by the US FDA for the purpose of cartilage regeneration and fracture healing and has been distributed mainly in developed countries. Currently, various types of LIPUS devices for the purpose of cartilage regeneration and fracture healing are being sold in Korea. Accordingly, the demand for LIPUS devices in Korea continues to increase, and several medical device companies are developing products to upgrade LIPUS devices.
Ultrasound for treatment
Ultrasound is an acoustic pressure wave with a frequency exceeding the human hearing range (20 Hz to 20 kHz) and is a form of mechanical energy transmitted through biological tissue and is widely used in the medical field.
High intensity treatment ultrasound
High-intensity therapeutic ultrasound is used to treat tumors by selectively heating tissue and causing necrosis.
Low intensity treatment ultrasound
Low-intensity therapeutic ultrasound, similar fracture to high-intensity ultrasound, is used for skin lifting by heating subcutaneous tissue to induce necrosis, as well as reducing joint stiffness and muscle spasms in sports medicine and musculoskeletal treatment and promoting healing and cartilage cell regeneration.
These therapeutic ultrasounds are used according to the target, purpose, and characteristics of the treatment, as shown in the table below, using three physical effects: mechanical effect, resonance effect, and thermal effect.
Principle of low-intensity pulsed ultrasound treatment device
Low-intensity pulsed ultrasound treatment devices are used as an effective treatment method in various areas such as fracture treatment, orthodontic treatment, lost tooth regeneration, cartilage and soft tissue regeneration, and drug delivery using sonophoresis. Radiating low-intensity ultrasound to the fracture site or joint cartilage causes activation of osteoblast and cell membranes when physical vibration stimulation is applied. With this principle, in addition to fracture healing, effects such as treatment of damaged tendons and reduction of inflammation are achieved.
For the purpose of fracture treatment, non-focused pulsed ultrasound with a frequency of 1.5 MHz, a pulse width of 200㎲, a pulse repetition frequency of 1 kHz, an irradiation intensity of 30mW/cm2, and an acoustic pressure of 50kPa is generally used.
Depending on the specific purpose, the treatment time and pulse width conditions can be adjusted and applied within the frequency range of 0.5 to 3 MHz and the intensity range of 30mW to 1 W/cm2.
Biophysical effect of ultrasound
Micro massage effect
· loosening effect on microscopic cell structure
· Friction effect that generates heat
· Oscillation effect of molecules inside of liquid medium
· Stimulation effect of diffusion that penetrate cell membrane
· Effect of control about complex molecule that is activated chemically
· Depolymerization of protein that consists nerve, muscle or collagen cement.
· Enlarging effect of excitatory synapse that combined with protein.
· Reversibility effect of viscosity of inter & extra-cellular colloidal substance.
· Penetration effect of characteristic drugs(Sonophoresis)
· Effects on nerves or circulatory system
· Effect of creating a cavity
Effects on nervous tissue
Relationship between ultrasound intensity and nerve conduction speed.
· When the ultrasound intensity is about 0.5W/cm2, the motor nerve conduction speed increase.
· When the ultrasound intensity is about 1~2W/cm2, the nerve conduction speed is increased.
Change in nervous tissue caused by ultrasound.
· Nerve cell bodies are more sensitive to ultrasound than the cerebral cortex
· White matter is more sensitive to ultrasound than the cerebral cortex.
· Various fiber tracts are more sensitive than cell nucleus to the damage caused from ultrasound
· Fibers in white matter can be damaged even in the absence of nerve cell destruction.
· Even if all nerve components are destroyed, the circulatory system may not be destroyed.
Chemical effect
Ultrasound has the effect of causing inversion of sugar, hydrolysis, and crystallization of supersaturated solutions. These effects occur directly or indirectly through the mechanical or thermal effects of ultrasonic waves.
Electrical effect
Because ultrasound affects the electrolyte solution, an electrical effect occurs by causing disturbance in the thin ion layer between the solid molecules and the electrolyte solution.
Effects on drugs
Ultrasound beams can penetrate chemicals dissolved in a medium or suspension through the skin into the tissues beneath the skin
※ Phonophoresis ※
This is a method of infiltrating drugs into tissues by using the change in cell permeability caused by the application of ultrasound. When a drug at a concentration of about 10% must be delivered to the surface tissue of the epithelium or dermis, a high frequency of 1.5 – 3 MHz is used.
If you need to deepen the penetration depth of the drug, select a lower frequency.
