Can the Same Technology Used to Break up a Kidney Stone Help to Heal a Tendon? (Sept '25)

Objectives:

• Understand how Extracorporeal Shockwave Therapy (ESWT) benefits musculoskeletal conditions
• Learn about the cellular mechanisms of ESWT and how it induces tissue regeneration and healing
• Explore the clinical applications of ESWT for chronic tendinopathies, including tennis elbow, achilles tendinopathy and plantar fasciitis.
• Discover the advantages of ESWT, including its non-invasive nature and minimal side effects
• Gain insights into the treatment process, including the frequency of sessions and expected outcomes

Give me the Easy Version…

Extracorporeal Shockwave Therapy (ESWT) is an advanced medical treatment method that has been used successfully to manage kidney stones. This technology originated from observations in airplane and aerospace technology, where shockwaves were found to have effects on tissues. Over time, scientists investigated the use of shockwaves in human treatments, leading to the development of the first shockwave lithotripter machine in 1974. Since the 1990's ESWT has been widely used for various musculoskeletal conditions, including tendon-related problems.

ESWT uses rapid and powerful pressure waves that can stimulate healing and tissue repair through a process called mechanotransduction. These waves generate mechanical forces that trigger biological responses in the body, leading to tissue regeneration and healing. At the cellular level, ESWT induces the activation and differentiation of stem cells, encouraging tissue repair. It also promotes collagen synthesis, reduces inflammation, and enhances blood vessel formation, aiding in the recovery of injured tendons.

The treatment itself is non-invasive, meaning there are no needles involved, and it generally has minimal side effects. ESWT is well-suited for athletes and active individuals since it allows continued activity during the treatment period. A typical course of treatment includes one session per week for 3-5 weeks, with the effects sometimes taking up to 12 weeks to fully manifest.

ESWT has shown to be effective in various musculoskeletal conditions, particularly in chronic tendinopathies such as tennis elbow, Achilles tendinopathy, and plantar fasciitis.

Give me the Details…

The introduction of extracorporeal shockwave therapy technology has been one of the largest advancements in the management of kidney stones. The knowledge was initially born from observations in airplane and aerospace technology between 1966 and 1972 when engineers noted the effect of shockwaves on tissues. Subsequently scientists began human investigations in 1972 and in 1974 the first shockwave lithotripter machine was developed and was able to break up kidney stones in a water bath. In 1979 the first shockwave device for humans was developed and the first human was successfully treated to break up kidney stones in 1980 ¹. In the early 1990s, extracorporeal shockwave effects on bone and soft tissues led to treatment indications for musculoskeletal disorders ². Today shockwave is used to treat all sorts of musculoskeletal regions and conditions including all types of tendinopathy and even bone stress injuries and fractures.

A shockwave is an abrupt change in pressure with a higher velocity than the speed of sound in the medium where it propagates. Basically, they are pressure waves with very short rise time, very high pressure, followed by a wave of negative pressure that is longer duration and much lower amplitude than the initial peak  ³. (See image below⁴)

There are 2 primary types of shockwaves used in treatment of musculoskeletal conditions, focused and radial shockwaves. A focused shockwave is as depicted above and generates an initially wide pressure field wave that becomes focused and converges at a particular depth. Focused shockwaves are applied to a small focal area of 2-8mm in diameter to optimize therapeutic effect such as on an area of tendinopathy. The shockwave energy per area of tissue treated is calculated in mJ/mm²  and referred to as the “energy flux density” ³. The 3 mains forms used to generate shockwaves include electrohydraulic, electromagnetic, and piezoelectric devices.

Radial shockwaves are not true shockwaves, but instead generate pressure waves in the tissue much more superficial at the level of the actual device applicator (see image below). The waves then diverge as they go deeper instead of converging on a particular foci like focused shockwaves ⁵. Because they are not true shockwaves this treatment modality can be referred to by multiple other names including "radial shock wave therapy", "Extracorporeal Pulse Activation Therapy" (EPAT), and "radial pressure wave therapy. Radial shockwaves work by a ballistic mechanism and are generated by the collision of a projectile metal piece accelerated by compressed air or electromagnetic induction onto an applicator head.

Radial shockwaves can be thought of like the waves generated from dropping a rock in a pond. Focused shockwaves are like converging the energy of sunlight through a magnifying glass to light a dried leaf on fire.

How do shockwaves help musculoskeletal conditions? Please give me the mechanism…

I am glad you asked because it goes back to our friend mechanotransduction...

Mechanotransduction is the biological process by which cells convert mechanical forces into biochemical responses, ultimately leading to tissue adaptation and repair. Shockwave is a type of mechanotherapy which is described as the employment of mechanotransduction for the stimulation of tissue repair and remodeling ⁶.

At the cellular level it has been demonstrated that shockwave therapy induces a shear stress and temporarily deforms some cytoskeletal proteins including actin and tubulin which reorganize within 3 hours. Ultimately the effect of shockwave therapy induces proliferation, migration, and differentiation of stem cells which contribute to tissue healing and regeneration. Many other cells are also targets including tenocytes, bone cells, endothelial cells and fibroblasts ⁴.

Shockwave therapy has been studied as a therapeutic tool in the treatment of chronic tendinopathies. Let’s first discuss the specific mechanisms at the cellular level. Shockwave has been shown to increase collagen synthesis through enhanced fibroblast proliferation. There is upregulation of tendon derived tenocytes and proliferation of anti-inflammatory cytokines. There is also a decreased metalloproteinase expression, which is an enzyme that degrades collagen, and a reduction of inflammatory interleukins. Shockwave can also help with pain through modifying substance P release and helps with neovascularization by induction of TGF-βI and insulin-like growth factor I ⁵.

What are the indications for shockwave therapy?

The International Society for Medical Shockwave Treatment (ISMST) approved standard indications as far as chronic tendinopathies go are as follows:

• Calcifying tendinopathy of the shoulder
• Lateral epicondylopathy of the elbow or tennis elbow
• Greater trochanter pain syndrome
• Patellar tendinopathy
• Achilles tendinopathy
• Plantar fasciitis with or without heel spur

Plantar fasciitis and tennis elbow are actual FDA approved indications for use of shockwave therapy ³.

A review article noted good evidence for the use of ESWT in calcific tendinopathy of the shoulder and plantar fasciitis (grade A recommendation = level I studies with consistent findings). Grade B recommendation (level II or III studies with consistent findings) was found for lateral epicondylopathy of the elbow, greater trochanter pain syndrome, patellar tendinopathy, and Achilles tendinopathy ⁷.

Clinically, how is extracorporeal shockwave therapy used?

Well, the nice part about shockwave therapy is that it is non-invasive, meaning no needles involved. Also, it has minimal side effects and is great for athletes and very active individuals because it allows for continued activity in most cases during the entire treatment period. The typical treatment period is one session per week for 3-5 total sessions. The effects from treatment can take up to 12 weeks.

This all sounds too good to be true, what are the downsides? Not many, but the actual treatment hurts, sometimes a lot. The good news is that most people feel better even immediately following the treatment due to effects on pain modification mentioned above. Also, the treatment is typically not covered by insurance, meaning you must pay out of pocket for it.

Concluding Remarks

Extracorporeal Shockwave Therapy (ESWT) has evolved from breaking up kidney stones to becoming a powerful tool in treating stubborn tendon and musculoskeletal conditions. By harnessing the body’s own healing mechanisms through mechanotransduction, shockwave therapy can stimulate tissue regeneration, reduce pain, and support long-term recovery—all without surgery or injections. While it’s not a “quick fix” and often works best alongside a structured rehab program, ESWT offers an exciting, evidence-based option for patients struggling with chronic tendinopathies. For many, it represents the bridge between ongoing pain and a return to the activities they love.

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