Extracorporeal shock wave therapy (ESWT)
Extracorporeal shock wave therapy (ESWT) is a non-invasive treatment method that utilizes high-energy acoustic waves to target injured soft tissues, aiming to alleviate pain and promote healing. Initially developed in the 1980s for treating kidney stones, its applications have expanded to include a range of musculoskeletal conditions such as tendonitis, plantar fasciitis, and tennis elbow. The therapy is thought to operate by reducing inflammation, breaking down scar tissue, and stimulating cellular healing through the delivery of shock waves.
ESWT can be administered in both low-energy and high-energy forms, with the former typically requiring multiple sessions and the latter often involving a single session that may necessitate anesthesia due to pain levels. Patients usually rest the affected body part on a soft membrane, where a conductive gel is applied, allowing the shock waves to penetrate the tissue. While considered a preferable alternative to surgery, ESWT may not guarantee resolution of all symptoms and can be costly, with variable insurance coverage. The therapy is generally viewed as low-risk, but its effectiveness remains a topic of ongoing debate, with limited definitive research supporting its widespread use.
Extracorporeal shock wave therapy (ESWT)
Extracorporeal shock wave therapy (ESWT) is a non-invasive form of treatment in which shock waves are applied to injured soft tissue so as to reduce pain and encourage healing. In ESWT, high-energy acoustic waves are used to deliver a mechanical force to the targeted soft tissues. It can be used to treat a wide variety of musculoskeletal conditions, including tendonitis, plantar fasciitis, and tennis elbow. Although little definitive research has been conducted on ESWT, physicians theorize that delivery of shock waves helps to reduce inflammation, break up scar tissue, and stimulate tissue healing at the cellular level. Because it is non-invasive and can be performed in an outpatient setting, ESWT is also sometimes considered a preferable alternative to surgery. ESWT rarely leads to any sort of complications. For these reasons, ESWT is generally viewed as a viable option for patients with chronic musculoskeletal conditions who have not responded well to more traditional treatments.
Background
Shock waves are the primary operative force in ESWT. A shock wave is a strong pressure wave existing in any elastic medium, such as air, water, or solid substances. While they are often associated with explosions or supersonic aircraft, shock waves can be produced by any phenomenon that creates violent changes in pressure. In shock waves, the wave front—the part of a wave where compression occurs—is subject to sudden and violent changes in stress, density, and temperature. This means that shock waves travel differently than normal sound waves. Specifically, shock waves move faster than sound waves and gain speed as their amplitude increases. On the other hand, shock waves also lose intensity more quickly than sound waves because some of their energy is expended on heating the medium through which they travel. Shock waves are also capable of altering the mechanical, electrical, and thermal properties of solids. This particular characteristic is what makes shock waves valuable in medicine.
To understand why shock waves are effective from a therapeutic standpoint, it is first necessary to examine the historic relationship between shockwaves and living organisms. When the first single-celled and multi-cellular organisms initially appeared during the early stages of Earth’s development, they were constantly exposed to violent events—volcanic eruptions, sustained earthquakes, and meteor impacts—that produced strong shock waves. Faced with repeated exposure to shock waves, living organisms had to adjust to the mechanical and pressure-related stimuli produced by such waves. As a result, living things eventually came to have sustained natural reactions to modulated shock waves. In the human body, exposure to modulated shock waves leads to healing and regeneration as a result of cellular and tissue interaction.
Over time, humans have utilized shock waves for many practical purposes, including in the design and construction of military weapons. Among other things, scientists also eventually realized that shock waves could have therapeutic applications in medical settings. When harnessed and modulated properly, the energy of acoustic pressure shock waves can be passed through the body to stimulate tissue regeneration without causing any lasting damage.
Overview
ESWT was first used in clinical practice in 1982. At the time, physicians discovered that ESWT could help with the treatment of certain urologic conditions. Specifically, it was used as a means of pulverizing kidney stones. As this practice became more widespread, doctors noticed that patients who underwent ESWT because of kidney stone problems ultimately displayed improved bone density and new tissue growth. This observation suggested that ESWT might have other useful applications tied to the treatment of musculoskeletal conditions.
In the simplest terms, ESWT is a therapeutic treatment in which shock waves are delivered to a targeted part of the body via pressurized air. A similar procedure known as focused shock wave therapy (FSWT) does the same thing using electromagnetic pulses. Some of the conditions most commonly treated using ESWT include plantar fasciitis, and a variety of tendinopathies like tennis elbow. A tendinopathy is a chronic progressive degeneration of a tendon. ESWT can also be used to treat conditions like greater trochanteric pain syndrome, medial tibial stress syndrome, adhesive capsulitis, avascular necrosis of the femoral head, osteoarthritis of the knee, and non-union of long bone fractures.
ESWT can be administered in low-energy and high-energy forms. Low-energy ESWT treatments are administered over the course of at least three separate sessions that are usually mildly painful at worst. High-energy ESWT treatments are delivered in a single session and can be painful enough to require local or general anesthesia. In either case, the procedure involved is essentially the same. During treatment, the patient is asked to lie back with the targeted body part resting on a soft, water-filled membrane. A conductive gel is then placed on the skin before a non-invasive probe that creates shock waves is applied. It is believed that these shock waves induce microtrauma to the targeted tissue. This microtrauma initiates a healing response from the body that promotes blood vessel formation and allows more nutrients to reach the affected area. This helps stimulate the repair process and relieves pain.
There are both advantages and disadvantages to ESWT. The biggest advantage is that ESWT is a non-invasive treatment option for conditions that are otherwise difficult to treat. As such, it can also be an effective alternative to surgery. Another advantage is that it carries little or no risk of complications. Still, ESWT is not without its drawbacks. Most important, there is no guarantee that ESWT will resolve all of a patient’s symptoms. In addition, ESWT can also be quite expensive, in part because it is not always covered by health insurance. Finally, ESWT is sometimes viewed as controversial because there is little clear evidence supporting its use and most studies that have been done on the subject suggest that it may only help a small number of patients.
Bibliography
Cluett, Jonathan. “Shock Wave Therapy for Tendonitis and Plantar Fasciitis.” VeryWell Health, 26 Jan. 2020, www.verywellhealth.com/shock-wave-therapy-for-plantar-fasciitis-2549421. Accessed 11 Feb. 2021.
“Extracorporeal Shock Wave Therapy.” FootCareMD, 2021, www.footcaremd.org/conditions-treatments/injections-and-other-treatments/extracorporeal-shock-wave-therapy. Accessed 11 Feb. 2021.
“Extracorporeal Shockwave Therapy (ESWT).” Physiopedia, 2021, www.physio-pedia.com/Extracorporeal‗shockwave‗therapy‗(ESWT). Accessed 11 Feb. 2021.
“Frequently Asked Questions.” Excellence Shock Wave Therapy, 2021, www.eswtusa.com/faqs. Accessed 11 Feb. 2021.
“Shockwave Therapy.” Cleveland Clinic, 2021, my.clevelandclinic.org/canada/services/shockwave-therapy. Accessed 11 Feb. 2021.
“Shockwave Therapy.” Orthohealing Center, 2021, www.orthohealing.com/procedures/eswt-treatment. Accessed 11 Feb. 2021.
“Sports Medicine Practitioners Embrace Benefits of Extracorporeal Shock Wave Therapy.” Mayo Clinic, 5 Feb. 2019, www.mayoclinic.org/medical-professionals/physical-medicine-rehabilitation/news/sports-medicine-practitioners-embrace-benefits-of-extracorporeal-shock-wave-therapy/mac-20454275. Accessed 11 Feb. 2021.
“What Is a Shock Wave?” Sanuwave, 26 Feb. 2020, www.sanuwave.com/post/what-is-a-shock-wave. Accessed 11 Feb. 2021.