The Biomechanics of High-Intensity Laser Therapy and Extracorporeal Shockwave Therapy

Biomechanics of Extracorporeal Shockwave Therapy: 

The original shockwave technology was used to disintegrate kidney stones, but with the progression of this technology over time, it has been used for more musculoskeletal therapeutic purposes. The newer technology uses an acoustic mechanical wave, or soundwave, that creates a biological response at the cellular and molecular level of the tissues. 

Mechanism of Action / Biological Response: 

There are several mechanisms for extracorporeal shockwave therapy including physically, chemically, and biologically. During the physical phase, the shockwave creates a pressure on the tissues which results in the reflection, refraction, absorption, and transmission of energy into the tissues. Following the mechanical stimulation of the tissues, called mechanotransduction, several cell signaling pathways are promoted via adenosine triphosphate (ATP). The sound wave will stimulate the permeability of cell membranes by affecting the ion channels and  allowing ions to flow more freely into the cell. There are also several biological effects which result from the application of extracorporeal shockwave therapy (ESWT) including angiogenesis, or the growth of new blood vessels, which can be helpful in increasing the blood supply to damaged areas which will help repair damaged tissue. In addition, ESWT is also shown to increase nerve regeneration, decrease inflammation, increase wound healing, and heal bone non-union. 

Clinical Indications:

ESWT can be utilized for several musculoskeletal disorders. It is especially useful in calcific tendinopathies, however, it is not limited to this. It is also used for lateral and medial epicondylitis (tennis or golfers elbow), plantar fasciitis, patellar tendinopathy, achilles tendinopathy, and bone non-union. It has also been shown to be effective in treating patients with osteoarthritis. For example, in the knee joint, the new functional proteins from the biological response modify the cartilage and subchondral bone. Studies have shown that an increase in chondrocyte and osteocyte activity results in cartilage repair and subchondral bone regeneration. This results in a chondroprotective effect which helps with the decrease in cartilage degradation and an increase in healing of the meniscus in the knee.

How Extracorporeal Shockwave is Utilized at MPS:

ESWT is considered an effective alternative to other treatment methods because it is safe, effective, and non-invasive. Here at Midwest Pain Solutions, we use the extracorporeal shockwave therapy to help manage the effects of osteoarthritis. Specifically, its positive effects on cartilage and subchondral bone. Overall, this treatment can help reduce pain caused by osteoarthritis, plantar fasciitis, and tendinopathies and increase the overall function of the targeted joint. 

Sources:

https://pubmed.ncbi.nlm.nih.gov/29406349/ 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7670564/ 

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Introduction: 

The founder of laser therapy is a Hungarian physician by the name of Endre Mester. He began experiments on the positive biological effects of lasers in the 1960s and discovered an increase in wound healing on rats with burns. From there, further therapeutic uses have been discovered and are utilized in healthcare today. 

Mechanism of Action / Biological Response:

The mechanism behind laser therapy and its influence on the body is quite complex. First, lasers are made with monochromatic light with a narrow bandwidth. This is uncommon in nature which results in the body having to resort to more adaptive measures in response to such stimulus. When light hits our cells, it has both photochemical and photobiological effects on our tissues and will stimulate certain cell functions. For example, light absorbing molecules called chromophores will become active and allow for small amounts of single oxygen molecules to build up. This is significant because oxygen is a free radical which will influence the production of adenosine triphosphate (ATP) which gives energy to the cell. Secondary to this, there are several cell processes that follow including an increase in cell metabolism and collagen production, an increase in the action potential of nerve cells, stimulation of the formation of DNA and RNA in the cell nucleus, local effects on the immune system, and an increase in the production of new blood vessels. The laser also has effects on pain. It influences the release of endorphins, which are the body’s natural opioids. It decreases bradykinin which is a pain modulator. It increases the level of serotonin in the blood which assists with the acceleration of the inflammatory process. Finally, tissues exposed to the laser show decreased activity of the neurons that sense pain, or C-fibers. In addition to its influence on pain and the inflammatory process, it also helps with wound healing as it activates macrophages and other immune cells. 

Clinical Indications:

High Intensity Laser Therapy (HILT) can be utilized to treat a variety of conditions including patellofemoral pain, sub acromial pain, low back pain, and knee osteoarthritis. It is effective in treating various conditions because of its effects on the tissues. It accelerates connective tissue repair by affecting the function of fibroblasts which are the precursor cells for connective tissue. Connective tissue is present throughout the body and makes up our cartilage in our joints: the meniscus in the knee, our discs between our vertebrae, and the joints between bones. Several studies have shown that HILT produced more cumulative and longer lasting effects on knee pain caused by osteoarthritis compared to low intensity laser, ultrasound, and TENS. This is due to the ability of the high intensity laser to penetrate deeper into the tissue to stimulate soft tissue metabolism and promote changes. It was also demonstrated that HILT helps with the reduction of pain in patients with osteoarthritis. The mechanism behind this is that the laser stimulates nerve fiber regeneration and modulates the “gate control system” to reduce pain. The gate control theory is especially important in treating patients with chronic pain. In the “gate control system,” we sense pain in the brain when the gate is open. When the gate is open, pain signals can pass through to the brain where pain is perceived. If the gate is closed, pain signals traveling to the brain are restricted and the pain won’t be perceived. By stimulating nerve fiber regeneration, this regulates the gate control system and helps with the overall reduction in chronic pain. 

How High-Intensity Laser Therapy is Utilized at MPS:

At Midwest Pain Solutions, we utilize high intensity laser therapy (HILT) to treat chronic pain by improving blood flow, reduce swelling, allow for cell growth and tissue repair, enhance the regeneration of nerves, and to repair scar tissue. We treat many conditions including low back pain, osteoarthritis of the knee, hip, shoulder, and spine, and many more conditions. The specific high intensity lasers used at our practice were founded and patented by the Draeger Family. They founded a company called Crystal Med Tech where they specialized in producing the highest powered therapeutic lasers which have the ability to penetrate 4-8 inches deep. Most lasers, even other high intensity lasers, can only penetrate centimeters to a half an inch deep. Tissue changes cannot be stimulated in the body if the tissue cannot be touched by the laser. With our state-of-the-art technology, we have the ability to penetrate deeper into the joint, address the tissue and pain at its root, and allow for more lasting effects. 

Sources:

Tuner, J., & Hode, L. (2002). Laser Therapy: Clinical Practice and Scientific Background. Prima Books. 

https://pubmed.ncbi.nlm.nih.gov/37458008/