Sound Wave Therapy (ESWT): Uses in Physical Medicine and Rehabilitation
Extracorporeal shock wave therapy (ESWT) involves the transcutaneous application of high-energy acoustic waves. These waves are used either to break down tissue or to promote healing and repair.
Focused ESWT applies acoustic waves transmitted in a narrow or focused pattern. This noninvasive treatment emerged as lithotripsy to eliminate kidney stones. Lithotripsy was first used in the early 1980s.
Researchers began to examine other potential clinical applications for focused ESWT and another form of shock wave therapy known as radial ESWT. As interest in these modalities grew, researchers began exploring their therapeutic potential. Numerous research teams shared findings suggesting that ESWT could be used as a therapeutic tool during the 1990s and early 2000s.
Extracorporeal shock wave therapy device.
Radial ESWT: How It Works
Radial ESWT is currently being used as a therapeutic tool to promote healing and reduce pain in patients with a variety of musculoskeletal and neurological diagnoses. Compressed air accelerates a projectile up to 80 to 90 kph within a guiding tube that strikes a metal applicator placed on the patient's skin. The kinetic energy is converted into a radial shock wave.
Dr. Michael C. Wainberg, a physiatrist at Mayo Clinic's campus in Rochester, Minnesota, discusses the potential uses of ESWT for patients in the physical medicine and rehabilitation setting. "The interest in ESWT among physiatrists is expanding rapidly," notes Dr. Wainberg.
"Our colleagues at Mayo Clinic Sports Medicine Center in Minneapolis are currently using radial shock wave therapy to treat patients with musculoskeletal disorders, and physiatrists at Mayo Clinic's campus in Rochester, Minnesota, are providing this treatment to patients with musculoskeletal and neurological disorders as well," adds Dr. Wainberg.
Potential Uses of ESWT
Dr. Wainberg notes that multiple published studies have examined the use of ESWT in patients with musculoskeletal disorders and spasticity related to neurological diagnoses. Here are some examples:
- Lateral Epicondylitis: A study published in Europa Medicophysica in March 2005 concluded that patients with lateral epicondylitis refractory to conservative care who were treated with radial ESWT experienced a decrease in pain and functional impairment and an increase in the pain-free grip strength test.
- Spasticity Related to Stroke: A study published in the November 2017 issue of the Journal of Stroke and Cerebrovascular Diseases demonstrated encouraging results when testing the use of ESWT in patients with spasticity related to stroke.
ESWT for Tennis Elbow.
Additional Research
Here are some studies that provide additional information about ESWT:
- Spacca G, et al. Radial shock wave therapy for lateral epicondylitis: A prospective randomised controlled single-blind study. Europa Medicophysica.
- Guo P, et al. Positive effects of extracorporeal shock wave therapy on spasticity in poststroke patients: A meta-analysis. Journal of Stroke and Cerebrovascular Diseases.
- Marinelli L, et al. Effect of radial shock wave therapy on pain and muscle hypertonia: A double-blind study in patients with multiple sclerosis. Multiple Sclerosis Journal.
- Wu Y-T, et al. Extracorporeal shock waves versus botulinum toxin type A in the treatment of poststroke upper limb spasticity: A randomized noninferiority trial. Archives of Physical Medicine and Rehabilitation.
Adverse Events and Contraindications
According to Dr. Wainberg, the list of adverse effects (AEs) associated with ESWT is fairly short. Mild AEs include transient discomfort, skin erythema, and localized swelling.
"Thus far, the available data for ESWT are promising," says Dr. Wainberg. "Further studies are needed to identify the mechanism or mechanisms of action, optimal shock wave characteristics, and appropriate dosing for this form of treatment.