The Wonders of Extracorporeal Shock Wave Therapy (ESWT): A Non-Invasive Solution for Pain Relief

The Wonders of Extracorporeal Shock Wave Therapy (ESWT): A Non-Invasive Solution for Pain Relief

Introduction to ESWT

The Physical Properties and Biological Effects of ESWT

Physical Properties of ESWT

• Mechanical Effect: When shock waves enter the human body, they interact at the interfaces of different tissues, producing this effect. It helps in manipulating the tissues at these interfaces.
• Cavitation Effect: Micro-bubble nuclei present in the fluid between tissues vibrate under the influence of shock waves. When the intensity of the shock waves exceeds a certain threshold, these bubbles grow and collapse, creating the cavitation effect. This effect aids in breaking down adhesions and improving tissue permeability.
• Thermal Effect: As shock waves propagate through biological tissues, their vibrational energy is continuously absorbed by the tissues, resulting in the thermal effect. It can promote local blood circulation and accelerate tissue metabolism.

Biological Effects of ESWT

• Tissue Damage Repair and Reconstruction: It activates the body's natural repair mechanisms, promoting the regeneration and reconstruction of damaged tissues.
• Tissue Adhesion Release: By breaking down the fibrous bands that cause tissue adhesions, ESWT restores the normal mobility of tissues.
• Blood Vessel Dilation and Angiogenesis: It widens existing blood vessels and stimulates the growth of new blood vessels, improving blood supply to the affected area.
• Analgesic and Nerve Ending Blocking: ESWT inhibits the transmission of pain signals by blocking nerve endings, providing effective pain relief.
• High-Density Tissue Fragmentation: For high-density tissues like calcified deposits, ESWT can break them down into smaller particles, which are then absorbed by the body.
• Inflammation and Infection Control: It regulates the body's inflammatory response, reducing inflammation and helping to control infections in the treated area.

Types of Extracorporeal Shock Waves

Classification by Wave Source Generation Principle

• Electrohydraulic Shock Waves: These are generated by high-voltage discharge at one end of an underwater electrode. The electrohydraulic effect from the nanosecond-level intense pulse discharge produces shock waves. After being refracted and focused by a semi-ellipsoid, the shock waves travel through water into the human body and act on the second focal point, forming a pressure pulse with a very steep pressure front. Their main advantages include a high peak value, large energy, stable pulse waveform, good penetration, short impact time, and low energy consumption during use.
• Piezoelectric Shock Waves: Hundreds of piezoelectric ceramic elements embedded in a water-filled spherical cap are used. Under the action of the same time and electrical pulse elements, these piezoelectric ceramics produce the same inverse piezoelectric effect, causing the ceramic sheets to vibrate mechanically and generate shock waves. They are characterized by low noise, small focal points, few stray waves, strong stability, and minimal tissue damage.
• Electromagnetic Shock Waves: A high-voltage coil, when energized, generates a pulsed magnetic field that pushes a metal diaphragm to vibrate in water, creating shock waves. Their benefits include low noise, no need for electrode replacement, low possibility of deviation, strong penetration, stable focusing, a long focal zone, and slight tissue damage.
• Pneumatic Ballistic Shock Waves: Compressed air is generated by an air compressor and controlled by the main unit to reciprocally push the impact block in the treatment handle. According to Newton's mechanical transmission principle, the impact block then strikes the treatment head of the handle that is in contact with the patient's treatment site, generating shock waves. They have no energy focus, a wide wave propagation range, flexible movement of the treatment head during treatment, and are particularly effective for soft tissues.

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Classification by Energy Focusing Characteristics

• Focused Shock Waves: These have a focused area with a concentrated energy treatment range. Their main advantages are high and concentrated energy, as well as strong targeting. Electrohydraulic, piezoelectric, and electromagnetic shock wave sources, which generate shock waves with focal points using the principle of spherical reflection and focusing, are classified as focused shock waves.
• Radial Shock Waves: These propagate outward in a radial pattern, similar to ripples in water. The energy coverage range is wide, but the energy flux density decreases as the propagation distance increases. They have a gentle output waveform, with treatment pressure and frequency starting from a low level and gradually increasing. The equipment is small in size, relatively low in cost, easy to operate, and has fewer adverse reactions. Pneumatic ballistic shock waves, generated by shock wave sources without focal points, belong to radial shock waves.

"Longest" Pneumatic Ballistic Extracorporeal Shock Wave Therapy Device

Clinical Applications of ESWT

It is suitable for biomechanical therapy, addressing myofascial trigger points and tendon insertion dysfunction.

• It can activate muscles and connective tissues and is used in acupuncture shock wave therapy.
• Specifically, it serves as an auxiliary treatment for frozen shoulder, lateral epicondylitis of the humerus (tennis elbow), and Achilles tendinitis. By applying this therapy, patients can experience maximum pain relief and improved functional recovery.