Extracorporeal Shockwave Therapy (SWT) is a non-invasive medical procedure that utilizes acoustic waves to stimulate healing in musculoskeletal tissues. This therapy transmits sound waves, characterized by a rapid rise to a high-pressure peak, through the skin to the affected area. The energy delivered by these waves initiates a biological response, promoting tissue regeneration and providing pain relief.
Understanding the Types of Shockwave Therapy
The mechanism of action for SWT is rooted in mechanotransduction, where the mechanical stimulus activates cellular processes. The acoustic pulses create micro-trauma at the cellular level, which stimulates the release of growth factors and promotes the formation of new blood vessels. This accelerates the body’s natural repair cycle and helps to break down calcified deposits.
Shockwave therapy is categorized into two primary types based on how the waves are generated and delivered. Focused Shockwave Therapy (FSWT) produces true shockwaves that converge at a specific, targeted point within the tissue. FSWT is a high-energy modality capable of deep penetration, reaching up to 12 centimeters, making it the preferred choice for treating deep structures, such as bone non-unions, and dissolving hard calcifications within tendons.
Radial Pressure Wave Therapy (RSWT), sometimes referred to as radial shockwave, generates pressure waves that disperse radially from the applicator head. These waves are lower in energy and penetrate more superficially, typically reaching depths of up to three to four centimeters. RSWT is often used for broader, more superficial soft tissue conditions, including muscle tightness and myofascial trigger points. The choice between FSWT and RSWT depends on the location, depth, and nature of the pathology being treated.
Established Clinical Applications
Current clinical guidelines endorse SWT for a range of persistent musculoskeletal conditions that have not responded adequately to standard conservative treatments. The therapy is widely accepted for various chronic tendinopathies, where it stimulates healing in damaged tendon fibers. Examples include plantar fasciitis, a common cause of heel pain, and Achilles tendinopathy, which affects the tendon connecting the calf muscle to the heel bone.
The medical community also recognizes the benefit of SWT for lateral epicondylitis, commonly known as tennis elbow, and for calcific shoulder tendinitis, where calcium deposits restrict movement and cause pain. For these tendinopathies, the acoustic energy helps to disperse the calcification and accelerate the remodeling of the tendon matrix. Beyond soft tissue, SWT is also indicated for bone pathologies, including delayed bone healing and non-union fractures, where it promotes osteogenesis.
Regulatory bodies have recognized the efficacy of this treatment modality for specific indications. In the United States, the Food and Drug Administration (FDA) has cleared devices for the treatment of chronic plantar fasciitis, lateral epicondylitis, and diabetic foot ulcers. Professional consensus recommends SWT as an appropriate step after initial rest, physical therapy, and medication have failed to provide relief.
Safety Protocols and Contraindications
A thorough patient screening is required before administering shockwave therapy. Several conditions represent absolute contraindications. Treatment is strictly avoided in patients who are pregnant, especially over the abdominal or pelvic region, due to risk to the developing fetus. Similarly, SWT is contraindicated over open growth plates in children and adolescents, as the energy could interfere with normal bone development.
The presence of a malignant tumor in the treatment area is an absolute contraindication because the therapy’s regenerative effects could stimulate tumor growth. Treatment is also prohibited over air-filled tissues such as the lungs or large intestines, as the shockwaves can cause damage when passing through the air-tissue interface. Patients with blood clotting disorders or those taking oral anticoagulants require careful consideration, as the mechanical action of the waves can increase the risk of hematoma or bruising.
Patients with a cardiac pacemaker or other implanted electronic devices should not receive SWT near the device, as the acoustic energy may interfere with its function. Common side effects include temporary redness (erythema), mild swelling, or localized pain at the treatment site. Treatment over an area that has received a corticosteroid injection should also be avoided until at least six to twelve weeks have passed, to prevent adverse tissue reactions.
Typical Treatment Course and Delivery Standards
A course of shockwave therapy typically involves three to five sessions. These sessions are scheduled one week apart to allow the body’s natural inflammatory and healing responses to progress between treatments. The duration of each individual treatment is short, often taking less than thirty minutes to complete.
The intensity and total number of pulses delivered during a session are adjusted based on the specific condition and whether it is acute or chronic. Lower energy settings are employed for more acute or sensitive conditions, while higher energy is reserved for chronic pathologies or to break up calcifications. A contact gel is applied to the skin before treatment to ensure efficient transmission of the acoustic waves from the applicator head to the tissue.
Patients should be prepared for mild to moderate discomfort during the procedure, although anesthesia is usually unnecessary. Following the session, patients can return to their normal activities, but they are advised to avoid strenuous, pain-provoking activities for up to 48 hours. It is recommended to use acetaminophen for post-treatment pain rather than non-steroidal anti-inflammatory drugs (NSAIDs), as NSAIDs may interfere with the healing process activated by the shockwave treatment.