Health Matters: Shock wave technology aids circulation

Conway McLean, DPM

Medicine and technology have become strange bedfellows. Many would say we have become too reliant, and depend on our studies and tests to identify any disease. The art of the physical diagnosis, whereby the practitioner, through touching, feeling, listening, even tapping, can determine what is the condition responsible, this is a forgotten skill. It is easier to order some high tech study or expensive test. Still, new technologies have obviously provided amazing new therapies and life-sustaining treatments.

One of the newest devices (although now commonplace) is termed shockwave therapy, more accurately extracorporeal shockwave therapy (ESWT). It’s a novel treatment, and rather odd when you think about it. Bursts of sound, similar to the sonic boom from a speeding jet, applied to inflamed, painful tissue, produces a powerful healing response. Because of this non-specific effect, ESWT has a wide range of clinical applications. And these varied uses continue to expand for multiple diseases, those of the musculoskeletal system…and beyond.

Although unusual in nature, it is not theoretical. It has been successfully and safely applied to various areas of the body, and for a host of complaints. Some particular and unique benefits include its non-invasive nature, that it can be repeated numerous times, and can be carried out in a relatively, safe manner with rare and mild side effects. Although there is still much to learn, shock wave technology has been the subject of numerous studies, documenting the benefits clearly. But not so clearly the mechanism.

Shock wave therapy is a noninvasive treatment consisting of the delivery of shock waves to injured soft tissue, to reduce pain and promote healing. Because there is no observable trauma, no recovery period is required, no anesthesia is needed. It provides an athlete with an effective treatment option that isn’t season ending. ESWT requires no downtime following treatment, unlike every surgical option.

The therapeutic use of shock wave is felt to have begun with the discovery of ruptured lungs in soldiers submerged during bomb explosions during WWII. In 1966, interest in the effects of shock waves on humans was the result of an accident at the Dornier company, investigating high velocity projectiles. In the early 1970’s, the interaction between shock waves and biological tissue in animals was extensively studied in Germany. Research by scientists led to the development of shock wave technology causing the disintegration of kidney stones.

Animal studies revealed the ability of shock waves to stimulate fracture healing. Research confirmed the influence of shock waves on osteoblasts, bone-forming cells, which become more active in the presence of ESWT. In 1988, the first shock wave treatment of a fracture non-union in a human was successfully performed in Germany. In the early 90’s, the first reports on the use of shock wave therapy for tendinitis were published.

We have made progress in understanding how shock wave works, with abundant research elucidating its biological and therapeutic effects. The mechanism of action is the result of the acoustic mechanical waves that are generated, acting at the molecular, cellular, and tissue levels to generate specific biologic responses. It seems to induce characteristic changes inside of cells, with conversion of the mechanical signal into biochemical changes.

There are a plethora of high quality studies demonstrating the benefits in a variety of musculoskeletal conditions. Some of the more common uses of shock wave include plantar fasciitis (heel pain), jumper’s knee (patellar tendonitis), tennis elbow, stress fractures, even acute muscle strains. All manner of tendinopathies, regardless of the location. This kind of versatility makes it popular with clinics and practitioners nationwide.

One of the most prevalent yet silent diseases of our time is peripheral arterial disease, in which “clogs” build up along the walls of our blood vessels. The result is reduced blood reaching our limbs and, subsequently, poor tissue health. One possible effect is that even the most mild trauma can lead to a wound that won’t heal. Another frequent consequence of PAD is pain in the foot or leg after walking a certain distance (intermittent claudication).

Lower limb PAD affects 20% of the population over 65 years of age, clearly not an uncommon condition. Recent studies have revealed a surprising fact: a majority of those suffering from PAD never experience intermittent claudication (the previously mentioned painful cramping occurring with a certain amount of ambulation). Because we don’t have medications that are effective options for this, this is typically treated surgically, not pharmacologically.

ESWT increases the production of certain chemical messengers of the body. These molecules stimulate the production of new blood vessels. Other benefits include lessened stiffness of the blood vessel walls, which also improves limb perfusion. In addition, shock waves seem to decrease the production of the neurotransmitter which causes pain.

Shock wave use has gone beyond simply breaking up gallstones. Bold new uses, unimagined benefits have been discovered. The benefits to musculoskeletal problems are now well established and beyond question. Of the new directions for ESWT, perhaps most exciting is the ability to enhance blood flow, specifically perfusion. This is the term describing the amount of blood reaching the target tissue. This is a real problem, especially for those with diabetes.

Having open arteries is of less benefit if the blood and critical nutrients can’t get to the tissues. Shock wave appears to be effective in improving perfusion, making it helpful in treating wounds that won’t heal because of inadequate flow. Physicians have taken notice. It’s being used to help heal skin flaps, a common plastic surgical procedure. Because of the benefits to tissue perfusion, ESWT has found success in the treatment of chronic skin ulcers. Clinical trials have shown clear benefit to diabetic ulcer healing. 

Extracorporeal shockwave therapy has recently emerged as a novel, safe, and effective treatment option for a variety of conditions. It has provided a whole new modality for healing and pain. The application of physical energy, in the form of shock waves, apparently has the ability to influence cellular events in the body, with favorable biological consequences: promoting the repair of compromised or injured tissues.

Despite the benefits and lack of complications, the mechanism of action by which ESWT leads to improvement in arterial blood flow in the presence of PAD is only now being revealed. Research on the topic has been inadequate. Standardized treatment guidelines are yet to be established. But the ability to conveniently and safely improve blood flow, and aid in the healing of chronic tendon and ligament problems, makes this a beneficial, safe technology. In contrast to many traditional approaches, shock wave allows us to enhance healing. I would say that’s a sound idea.

Editor’s note: Dr. Conway McLean is a physician practicing foot and ankle medicine in the Upper Peninsula, with a move of his Marquette office to the downtown area. McLean has lectured internationally on wound care and surgery, being double board certified in surgery, and also in wound care. He has a sub-specialty in foot-ankle orthotics. Dr. McLean welcomes questions or comments atdrcmclean@outlook.com.


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