Shockwave Therapy — How It Works & What It Treats

Shock wave therapy has many biological benefits including:

• It is a non-invasive method for treating acute and chronic pain
• The treatment does not require anesthesia
• Decreases pain
• Increases mobility
• It has limited side effects
• It is commonly used for the treatment of musculoskeletal conditionsShockwave therapy is cost-effective

• Electrohydraulic Generation Principle
• Piezoelectric Generation Principle
• Electromagnetic Generation Principle
• Radial or Ballistic Generation Principle

Four generating principles in the field of shock waves are Electrohydraulic, Electromagnetic sources, and Piezoelectric sources, and the Radial or Ballistic Generation Principles. The shock wave emitted by most of the equipment has a focal zone that is several centimeters ahead of the generator. The therapeutic effects occur where most sonic waves are gathered in the focal zone, so this is often the action spot. The shock wave is transmitted through the coupling medium into the tissue creating a focal zone. It is necessary to make sure that the target area is in the focal zone during the shock wave treatment.

Parameters include acoustic energy, energy flux density (EFD), pressure distribution, and the total energy at the second focal point.
The energy flux density (EFD) of the focused shock wave used for the treatment of muscular trigger points is between 0.05 and 0.25 mJ/mm2. To avoid tissue damage the shock wave frequency applied to the trigger point should not exceed 4 Hz. Based on the thickness and depth of the muscle, the energy flux density (mJ/mm2) is selected. The energy flux density should be selected in such a way that the pain induced by the shock waves is tolerable for the patient. For the radial shock waves, the same method applies. Extreme caution should be taken while using small surface shock transmitters with a small surface as they generate high peak pressures, to avoid hematomas. The shock wave frequency is 10 to 15 Hz, 15 Hz frequency generally causes less pain. When using a combination of focused and radial shock waves in trigger point therapy, the trigger points are first treated by applying 200 to 400 focused shock waves. It is then followed by the radial shock wave transmitter, applying 3000 to 4000 radial shock waves.

Frequency: It is ideal to give one session per week for most patients. These intervals give muscles time to recover from the irritation, which the patient might feel for up to three days.

Shockwave therapy has a positive and negative phases. The positive phase produces direct mechanical forces, whereas the negative phase generates cavitations and gas bubbles that subsequently implode at high speeds, generating a second wave of shockwaves. It uses high peak pressure followed by low amplitude, short duration, and short rise time. They have a single pulse, with a high-pressure amplitude (0-120 MPa) and a wide frequency range (0-20 MHz). Whereas ultrasound waves have approximately 1000 times lesser peak pressure than a shockwave. Shockwaves are low-frequency pressure disturbances that travel rapidly in three-dimensional space, associated with a sudden rise from ambient pressure to their maximum pressure. Significant tissue effects include cavitations, which are consequent to the negative phase of the wave propagation.
The whole process does not produce any thermal effect, it promotes revascularization, stimulating proliferation and osteoprogenitor differentiation, increases leukocyte infiltration, and amplifies growth factor and protein synthesis to stimulate collagen synthesis and tissue remodeling.

APPLICATION
The patient is assessed by the physiotherapist during his first visit to confirm that he is an appropriate candidate for shockwave therapy. The treatment is started by applying gel to the treatment area. The applicator or therapy head is directly placed on the area. A medium of gel is required for the transmission of the waves through the patient's skin. The parameters are set and the intensity is applied according to the comfort of the patient (there is no standardized protocol for the treatment of musculoskeletal conditions). It can be used in conjunction with treatment-specific exercises, and activity modification. Depending on the results, the patient is advised to take the shockwave therapy once a week for 3-6 weeks.

Shockwave therapy is most commonly used in the treatment of common musculoskeletal conditions. These include:

• Acute and chronic muscular pain in cervical and lumbar spine regions.
• Chronic tendinopathy
• Calcific tendinosis of rotator cuff muscles
• Frozen shoulder
• Dorsalgia
• Tennis elbow
• Golfers elbow
• Carpal tunnel syndrome
• Sciatic pain
• Tensor fascia late syndrome
• Iliotibial band friction syndrome
• Greater trochanteric pain syndrome
• Avascular necrosis of the femoral head
• Medial tibial stress syndrome
• Osteoarthritis of the knee
• Patellar tendonitis
• Jumper's knee
• Bursitis
• Metarsalgia
• Tibialis anterior syndrome
• Achilles tendonitis
• Plantar fasciitis
• Heel spurs
• Fracture
• Exostosis of small joints
• Repetitive strain and overuse injuries.