The difference between electromagnetic focused shock wave and piezoelectric shock wave

🔹 Extracorporeal shock wave therapy is a mature technology combining physics and medicine. It has the characteristics of non-invasive, high safety, non-invasive, infection avoidance, time-saving and fast, etc. It is known as "bloodless scalpel" and "pain green treatment and management expert"

The source of the shock wave

🔹 The transmission form of shock wave can be divided into focusing type, diverging type and so on.

Shock wave sources have the following forms:

① Air pressure ballistic shock wave source;

② Piezoelectric crystal shock wave source;

③ electromagnetic shock wave source;

④ Hydraulic and electric shock wave source.

Among them, the focus of the hydraulic shock wave is like an ellipsoidal body, the focus of the electromagnetic shock wave is too narrow, and the focus of the piezoelectric shock wave is smaller and has stronger targeting, which is the most accurate of the three focusing shock waves.

Biological effects of shock wave

🔹 Biological therapeutic effects of shock wave include:

① Tissue injury repair and reconstruction;

② Tissue adhesion release;

③ Vasodilation and vascular regeneration;

④Analgesia and nerve terminal blocking effect;

⑤High density tissue lysis;

⑥ Inflammation and infection control.

The difference between focused and divergent shock waves. So, what are the specific differences between focused shock wave and divergent shock wave?

（1） Difference of production principle

🔹 The divergent shock wave mainly generates energy through the air pressure trajectory, and the energy focuses on the skin surface and enters the tissue in the divergent form to treat superficial tissue diseases. The advantages of divergent shock wave are simple operation and relatively safe, while the disadvantages are divergent energy, poor precise targeting and shallow penetration.

🔹 Focused shock wave mainly generates energy through piezoelectric, hydraulic and electromagnetic focusing, with fast propagation speed and less energy loss, which can treat deep lesions. The advantages of focused shock wave are large energy, strong targeting and deep penetration, while the disadvantages are precise positioning and high operation requirements.

🔹 Among them, piezoelectric focused shock wave overcomes the technical bottleneck of traditional focused shock wave, successfully improves the focusing accuracy, greatly extends the service life of treatment, and reduces the working noise of the machine. It is undoubtedly the development direction of focused shock wave technology and a new choice for clinical treatment.

（2）Physical mechanism difference

🔹 Shock wave is a kind of special acoustic wave in essence, which has the characteristics of high peak pressure, short period and wide wave frequency.

🔹 The traditional shock wave is divided into hydraulic, piezoelectric and electromagnetic shock wave, which are collectively called focused extracorporeal shock wave (f ESW). The peak pressure of fESW can reach 100MPa, and the period of a single wave is less than 1μs. Another type of shock wave device was also produced and put into use, called radialextrac orporeal shock wave (rESW). Compared with ESW, rESW has a smaller peak pressure (<1MPa) and a longer single wave period (>1000μs).

（3）Time to maximum pressure: 

🔹 The focused shock wave can reach its peak in nanoseconds, while the divergent shock wave needs microseconds. Note that 1 microsecond (μs)= 1000 nanoseconds (ns), that is, the frequency of the focused shock wave is much higher than the divergent shock wave. The maximum peak pressure of the focused shock wave is much higher than that of the divergent shock wave.

Energy distribution difference

🔹 With the increase of depth, the energy of the focused shock wave will not decay basically, and the energy is the maximum at the focus point, which can maximize the energy to the lesion and the affected area.

🔹 Divergent energy is divergent, the energy is the largest on the skin surface, its energy with the increase of depth and sharp dissipation, every 1 cm of divergent shock wave into the human body, the energy is about 50% attenuation.

🔹 Therefore, because the energy of divergent shock wave is the largest on the skin surface, the skin of patients will often be red and swollen after treatment, while the skin will basically not be red and swollen after focused shock wave treatment.

Difference in scope of application

🔹 First of all, they can be used for the treatment of superficial tissues within 2 cm.

🔹 Secondly, the divergence is more suitable for the pain of superficial tissues and larger muscle groups, and is suitable for the disease of mobile beating. For example, tennis elbow, tenosynovitis, Achilles tendinitis, stroke caused muscle spasm, neck and shoulder overall muscle group release, lumbar and dorsal fascia chain release, etc.

🔹 Thirdly, focused shock wave has advantages for bone diseases, deep and clear bone and muscle diseases, such as calcified supraspinatus tendinitis, piriformis syndrome, deep fascial pain points, bone nonunion and delayed healing, early femoral head necrosis and other diseases.

Operation usage difference

🔹 Diverging shock wave is often combined with movement method and fixation method. In treatment, high-frequency handheld treatment gun is often used to move and comb the muscle groups around the pain point, and then fixed impact is carried out on the pain point, and moderate hand-held pressure is applied. Due to the reciprocating movement of the bullet in the trajectory, it will cause a burden on the operator's hand when used.

🔹 Most of the focused shock wave is fixed shock treatment, electromagnetic and hydraulic shock wave often use large water sac probe treatment, so it is fixed shock; Piezoelectric shock wave therapy instrument, using hundreds of piezoelectric ceramic crystal installation design of hand-held impact handle, using the mobile method to find the pain point, find the pain point to fix the treatment, without hand-held pressure treatment, will not cause a burden on the operator's hand.

Complementary applications of focus and divergence

1. Selection strategies for diseases with different depths.

🔹 The divergent type is more suitable for the pain of superficial tissues, large muscle groups in the area, and suitable for the disease of mobile beating; Focused shock wave has obvious advantages for bone diseases, deep and clear pain points of skeletal muscle diseases.

2. Combination treatment of the same disease in different periods.

🔹 For the same disease, different periods of treatment require different energy. For example, for patients with bone nonunion and delayed bone healing, focus beating can be used first for the first few treatments. Focus beating has large energy and concentration, which is easy to form microdamage and induce osteogenic response. After several treatments with divergent shock wave fixation method can be used, while reducing the patient's pain.

3. Combination treatment of single treatment for the same disease.

🔹 For many diseases, divergent shock waves can be used first and then focused in a single treatment.

For example, for calcifying supraspinatus tendinitis, divergent shock wave can be used to move and release the tissue around the pain point, and then focused shock wave can be used to target and fix the calcifying pain point. In this way, both holistic treatment and accurate treatment are achieved.

🔹 A large number of evidence-based medical data show that both types of shock wave techniques have good effects in clinical application. Through the above comparative analysis, it can be seen that focus and divergence have their own advantages, but also have some shortcomings. Focus and divergence are not absolute superior or inferior, let alone one replacing the other, but complementary shock wave combination treatment methods.

🔹 As a clinical shock wave treatment center, there should be both focused shock wave and divergent shock wave. As a shock wave practitioner, only by clearly mastering the physical properties of focus and divergence can the application be targeted, realize "overall treatment + precision treatment", expand the scope of application, improve the treatment effect, and improve the level of scientific research and academic research.