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This lecture deals about the topic ESWT in following subcategories;
1. Basics principles & production of ESWT
2. Indications & Contraindications of ESWT
3. Biological & Therapeutic effects of ESWT
4. Methods of application / Treatment procedure – An overview of clinical application
1435 – 1436H – 1ST SEMESTER - PHT 221 – SECTION – 1099- 243
4/16/202
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Following completion of this chapter, the student therapist will be able to:
 Describe the mechanical characteristics of extracorporeal shock waves.
 Compare & list down some of the indications, contraindications, precautions & dangers of ESWT.
 Discuss the cellular effects of extracorporeal shock wave therapy on bone and tendons.

Safely & effectively to demonstrate the methods of application to various segments of the body as a treatment.


Shock wave is a sonic pulse that is characterized by the following physical parameters:
1. a high peak pressure (sometimes as high as 100 MPa, but usually around 50-80 MPa),
2. a fast initial rise in pressure (less than 10 nsec), a low tensile amplitude,
3. a short life cycle (usually less than 10 msec),
4. and a broad frequency spectrum (16-20 Hz).
The attenuation of shock waves in air is 1000 times more than through water because the attenuation is dependent on the velocity of the wave and density of the tissue.
Shock waves are generated within a water medium and applied through water-based coupling gel based on the assumption that the human body's makeup is similar to water


There are three methods of shock wave generation
1. Electrohydraulic,
2. Electromagnetic
3. Piezoelectric
1. ELECTROHYDRAULIC SHOCK WAVE
Electrohydraulic shock wave devices create a spark that discharges rapidly into the water, and vaporizes the surrounding water creating a gas bubble filled with the water vapor.
The gas bubble produces a sonic pulse and the subsequent implosion and a reverse pulse that causes another shock wave.
The expanding shock waves are reflected by the surface of the ellipsoid and refocused into the focal point.
Electrohydraulic shock wave devices are usually characterized by high-energy waves in focal volumes with fairly large axial diameters

2. ELECTROMAGNETIC SWT
Electromagnetic devices use a metal membrane and an opposing electromagnetic coil.
An electric current is passed through the coil producing a strong magnetic field. The resulting variable magnetic field forces the metal membrane away compressing the surrounding fluid medium and creating a shock wave.
The wave is passed through a lens to focus it at the desired target tissue. Electromagnetic shock wave devices tend to be used to create low-energy waves
3. PIEZOELECTRIC SWT
Piezoelectric shock wave devices pass electrical current through large numbers of piezocrystals mounted on the inside of a sphere.
The resulting expansion and contraction of the piezocrystals create a shock wave.
The piezocrystals are arranged in the sphere so that the resulting shock wave is very focused allowing for a high-energy density within a defined focal volume

a. Direct MECHANICAL and PHYSICAL effects b. BIOLOGICAL indirect effects
A. DIRECT MECHANICAL AND PHYSICAL EFFECTS
It comes from the piezoelectric properties of shockwaves. Extra
Corporeal Shock-Waves Therapy allows to involve the majority part of the cellular layers particularly deeply into the tissue where emission gives rise to a resonance effect able to provoke molecular ionization and increasing of membrane permeability.

B. BIOLOGIC EFFECTS
Tensile and shear stresses are created in the direction of shock wave propagation in biologic tissues. The tensile forces are greater than the tensile strength of the water and generate bubbles (cavitation).
BONE
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The effect of shock waves on bony tissue is thought to occur primarily at the interface between cortical and cancellous bone.
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It is thought that acoustic streaming causes cavitation and increases cell permeability allowing increased vascularity and bony regeneration.
More specifically, an increase in stromal cells seems to allow osteogenesis. Additionally, the increase in osteoprogenitor cells coupled with local increases in growth factor, neovascularization, and protein synthesis suggest that shock waves can improve the tissue environment for healing to occur
TENDON
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The suggested mechanisms for biologic effects of shock waves on tendons are the same as bone.
Direct mechanical stresses cause tensile and shear failure within the cellular matrix of the tendon. The resulting cavitation and indirect microjets cause the most damage at the interface of the tendon and bone.


Shock-wave therapy is based on the capability of delivering shorty pressure impulses into the cellular tissues, giving rise to the therapeutic effects.
 Transmission depends on the type of the body tissue. It is the best into the water.
 Into the human body, it penetrates upto 4 cm in depth.


Acoustic pulses are introduced into the body over a large surface area by using free moved applicator and cover the entire pain region
 This acoustic pulse is transmitted to the target tissue using coupling media as gel.

Chemical environment of cell is changed by the free radical

METHOD 1 – FOCUSED METHOD
• The trigger button on the applicator must be pressed with the middle and ring fingers
• This is used in the treatment of pain confined to specific area.
METHOD 2 – UNFOCUSED METHOD
• Continuous shock mode must be enabled by pressing the trigger button as well as the locking button provided on the applicator
• Alternatively the foot switch can be used
• This method is used when pain covering large area

 Epicondilytis ( Medial/ Lateral)
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Tendinitis and Tendinosis
 Calcifications e.g. shoulder
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Calcanear spur and plantar fascitis
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Pubalgia, Ischiatic intersection syndrome
 Jerking “ finger”
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Periostitis
 Coxarthrosis, gonarthrosis, rizoarthrosis,
 Pseudoarthrosis e.g. scaphoid

Fractures – Non union, Acute fracture of tibia, Femoral head necrosis and Total hip revision

Caution Side effects
• Not applied to target areas located above air filled tissue (lung)
• Region near large nerves, vessels, spinal column or head
• Swelling
• Reddening
• Hematomas
• Pain
• Skin lesion after cortisone treatment
• This side effects disappear after 3-7 days
• Application should not conducted until these signs disappear


Reset the shock counter to zero
 Start treatment at an application pressure of 1- 1.5 bar and a frequency of 5 Hz

 Continuous speaking with patient and cooperation is very important

Painful spots are localized by palpation
 The applicator applied to target tissue by moving it in a slow circular motion
 Coupling cushion can be used to insure perfect hygiene during treatment
 Coupling should be applied in sufficient amount to ensure optimal transmission of wave
 Cool of the area prior application to reduce pain sensation

 Start with energy about 5 bar
 If pain started to decrease , increase the energy gradually
 Energy is selected according to patient sensitivity

Energy level up to 3 bar is sufficient to achieve the desired effects

 Start with 5 Hz
 Test which frequency is suitable and tolerated by your patient (5Hz or 10 Hz)