The concept that light energy from a laser can reduce pain and inflammation, accelerate healing in damaged tissues, relax muscles, and stimulate nerve regeneration seems farfetched. Science, however, tells us these effects do occur. The question is, to what extent and is this based on wavelength and power?
“Wavelength and power determine the capacity of the laser to penetrate into the body. Once you are in the infrared spectrum and above 800 nanometers in wavelength, laser energy penetrates like x-rays, but to achieve depth you need significant power or energy,” Dr. Bruce Coren told SpineUniverse.
Laser therapy treatment on a male patient
"A 10-minute treatment with a 30-watt laser will produce 18,000 joules, which gives a significant pain relieving, anti-inflammatory and healing effect.”
Two Types or Classes Used in Physical Therapy
There are two classes of lasers being used in physical therapy; class 3 and 4. “Class 3 lasers are less than 500 milliwatts (mw) in power while class 4 lasers are greater than 500 mw,” Dr. Coren said. Class 3 lasers are sometimes referred to as cold lasers, and the therapy may be called LLLT for low-level laser therapy. In contrast, class 4 laser therapy is sometimes called HPLT for high-power laser therapy.
“The majority of neuro-musculoskeletal conditions respond better to a higher power and a higher dosage, which is a function of power output and time,” Dr. Coren commented. “The best results are going to be obtained with a laser that has 30 watts of power or more. A 10-minute treatment with a 30-watt laser will produce 18,000 joules, which gives a significant pain relieving, anti-inflammatory and healing effect.”
Patients usually begin to feel better after 1 or 2 treatments, although 5 or more may be needed to resolve the problem. “The more chronic and extensive the injury the more treatments are usually needed,” he added.
Properties of High-Power Laser Therapy
Dr. Coren talked to SpineUniverse about the beneficial properties of Laser Therapy:
Pain Relief: “Laser decreases nerve sensitivity by decreasing bradykinin; a pain eliciting chemical. It normalizes ion channels [cellular gatekeepers] and releases endorphins [body’s natural pain reliever] and enkephalins [related to endorphins] that produce an analgesic effect. It also has a pain-blocking effect on certain nerve fibers.”
Anti-inflammatory/Healing: “Laser increases ATP, which is stored energy [ATP is the acronym for adenosine triphosphate]. This increased energy accelerates the repair processes of the cell. Laser also causes a widening of the arteries and veins around the injury which helps to remove damaged cellular debris and increase nutrients and oxygen. White blood cell activity is enhanced leading to a more rapid repair process. Also, some molecules that increase inflammation are reduced, and beneficial antioxidants like superoxide dismutase are increased.
Accelerated Tissue Repair and Cell Growth: “Photons of light from lasers penetrate deeply into tissue and accelerate cellular reproduction and growth. As a result of exposure to laser light, the cells of tendons, ligaments, nerves and muscles are repaired faster.”
Improved Vascular Activity: “Laser light increases the formation of new capillaries in damaged tissue, which speeds up the healing process, and closes wounds quickly.”
Trigger and Acupuncture Points: “Laser is particularly effective in extinguishing painful trigger points. It is also an effective way of stimulating acupuncture points without the discomfort associated with needling.”
Reduced Fibrous Tissue Formation: “Laser therapy reduces the formation of scar tissue following tissue damage from repetitive motion injuries, cuts, scratches, burns or surgery.”
Faster Wound Healing: “Laser light stimulates the building blocks of collagen, which is important in the wound healing of damaged tissues. Collagen is the essential protein required to replace old tissue or to repair injuries. As a result, the laser is effective on open wounds and burns.”
Stem Cell Activation: “Laser increases the number of stem cells, which enhances healing.”
Where Laser Therapy Administered and Conditions Treated
High-power lasers are typically found in physical therapy clinics and chiropractic offices. Neck, back or joint pain usually responds quickly to laser therapy.
“Lasers are also very effective for inflammatory conditions, including peripheral neuropathy, tendonitis, bursitis, and capsulitis. Strains, sprains, and repetitive motion injuries all have an inflammatory component and can be successfully treated with laser,” he commented. “There is no particular condition that responds more quickly to laser. However, some patients will respond faster than others for the same condition as individual healing rates can vary.”
Laser therapy can be used as a stand-alone treatment, or with rehabilitative exercise therapy. “Rehabilitative exercises and laser therapy complement each other nicely,” explained Dr. Coren.
Lasers use light, and light is energy that can interact with tissue to induce biological effects, such as:
1. Anti-Inflammatory: Laser Therapy has an anti-edema effect as it causes vasodilation, but also because it activates the lymphatic drainage system which drains swollen areas. As a result, there is a reduction in swelling caused by bruising or inflammation.
2. Analgesic: Laser Therapy has a beneficial effect on nerve cells. It blocks pain transmitted by these cells to the brain which decreases nerve sensitivity. Also, due to the decreased inflammation, there is less edema and less pain. Another pain blocking mechanism involves the production of high levels of pain killing chemicals such as endorphins and enkephalin from the brain and adrenal gland.
3. Accelerated Tissue Repair and Cell Growth: Photons of light from lasers penetrate deeply into tissue and accelerate cellular reproduction and growth. The laser light increases the energy available to the cell so that the cell can take on nutrients faster and get rid of waste products. As a result of exposure to laser light, damaged cells are repaired faster.
4. Improved Vascular Activity: Laser light will significantly increase the formation of new capillaries in damaged tissue which speeds up the healing process, closes wounds quickly and reduces scar tissue. Additional benefits include acceleration of angiogenesis, which causes temporary vasodilation and increase in the diameter of blood vessels.
5. Increases Metabolic Activity: Laser Therapy creates higher outputs of specific enzymes, greater oxygen and food particle loads for blood cells.
6. Trigger Points and Acupuncture Points: Laser Therapy stimulates muscle trigger points and acupuncture points on a noninvasive basis providing musculoskeletal pain relief.
7. Reduced Fibrous (scar) Tissue Formation: Laser Therapy reduces the formation of scar tissue following tissue damage from cuts, scratches, burns or surgery.
8. Improved Nerve Function: Slow recovery of nerve functions in damaged tissue can result in numbness and impaired limbs. Laser light speeds the process of nerve cell reconnection and increase the amplitude of action potentials to optimize muscle healing.
9. Immunoregulation: Laser light has a direct effect on the immune system by stimulating immunoglobulins and lymphocytes. Laser emissions are absorbed by chromophores (molecule enzymes) that react to laser light. Upon exposure to the laser, the enzyme Flavin mononucleotide is activated and starts the production of ATP (adenosine triphosphate), which is the major carrier of cell energy and the energy source for all chemical reactions in the cells.
10. Faster Wound Healing: Laser light stimulates fibroblast development in damaged tissue. Fibroblasts are the building blocks of collagen, which is the essential protein required to replace old tissue or to repair tissue injuries. As a result, Laser Therapy is effective post surgically and in the treatment of open wounds and burns.