In the last two decades, extracorporeal shock wave therapy (ESWT) — a non-invasive procedure with virtually no down-time after treatment, has proven effective in treating certain common but troublesome tendon conditions, such as plantar fasciitis, tennis elbow and shoulder calcific tendinitis.
Shock waves, generated in specially designed ESWT devices, are acoustic pressure waves with a very unique waveform, i.e., a very rapid rise to a high magnitude and a very rapid fall time. These, when focused by an acoustic lens onto the targeted area in the human body, can result in certain biological effects.
The effects include interruption of “pain-spasm” cycles that occur in many chronic pain situations, reduction of pain by influencing the nerves carrying pain signals, and the release of certain growth factors in the targeted tissues, which may lead to the formation of new vessels (angiogenesis) and other biological effects associated with tissue healing.
While the nerve related effects can occur almost immediately, they may be temporary.
The release of growth factors, however, occurs over several weeks, resulting in a facilitation of regeneration and repair in chronically injured or degenerated tissues over the subsequent months.
ESWT has also been used to assist bone healing in certain situations of non-union or delayed union of fractures. More recently, ESWT has also been used in myofacial trigger point treatment for pain management
Mainly an outpatient treatment, an ESWT session typically takes 20 minutes per site.
In most cases, over 2000 shocks will be used per session, with no local anaesthetic needed. For the majority of conditions, one to three sessions, with the interval between each varying from four days to several weeks, would suffice.
The injured structure is first identified, and then precisely targeted by the ESWT device by means of real-time ultrasound guidance. Shock-waves are then delivered in rapid succession, ramping up from low levels to therapeutic levels.
The patients may experience some tolerable discomfort during treatment. This is usually described as a deep “hammering” feeling. While there is usually no pain after treatment, a small percentage of patients may experience slightly increased soreness for a few days. If this occurs, painkillers or a simple ice-massage can help.
There is no restriction to the number of times ESWT treatment can be carried out, as there is no long-term risk involved, provided treatment is carried out correctly.
ESWT should not be used in areas of tumor, infection or in the early and late stages of pregnancy.
Focusing and targeting of ESWT treatment needs to be accurate, especially where the site of treatment is close to structures such as the lung, the spine and any large blood vessels, as these could be damaged by poorly focussed ESWT.
As such, the International Society of Musculoskeletal Shock-Wave Therapy (ISMST) has recommended that ESWT be carried out only by trained physicians, using proper ESWT devices.
This article was republished with the permission of the original author Dr. Patrick Goh. Dr. Patrick Goh, a specialist sports physician, earned a MBBS degree from the National University of Singapore and a master’s degree in sports science from the United States Sports Academy in 1988. He was chief medical officer for Team Singapore at the 2000 and 2004 Olympic Games. For more information, visit ortho-intl.com.