"COLD LASER" BASICS

OK, forget about the popularized depictions of lasers as light sabers and alien death rays. In the therapeutic context, a laser is simply a source of electromagnetic energy that is monochromatic – providing a consistent wavelength that travels in the same direction.

Until recently, most medical lasers have been thermal or ‘hot’, in that they are capable of deeply penetrating and heating body tissue -- thus cutting, cauterizing or destroying it. Thermal lasers, such as those used in surgery, typically operate at power levels in excess of 25,000 mW.

Non-thermal, or “cold” lasers, are also capable of penetrating into human tissue, but do not heat the tissue sufficiently to cause damage. Non-thermal lasers, such as those indicated for Low Level Laser Therapy (LLLT) typically operate at power levels between 10 mW and 500 mW and are totally painless. They are a delivery mechanism for electromagnetic energy (at a specific wavelength within the infrared range of the electromagnetic spectrum) which triggers the cellular metabolic cascade discussed later.

A HISTORY OF LOW LEVEL LASER THERAPY (LLLT)

In the late 1960's, scientists in Europe began to research the use of very low powered lasers (less than 5 mW) to produce non-thermal effects, or ‘biostimulation,’ in human tissue. The first experimental applications of LLLT were reported in 1968, when researchers used ruby and argon lasers on non-healing or slow-to-heal ulcers. Later research substantiated the efficacy of LLLT to accelerate the healing of wounds, attenuate pain, and reduce tissue inflammation in both humans and animals. During the 1980’s, the use of more highly-powered lasers was investigated, though power levels were still very low by today’s standards. Power levels in LLLT devices today range from 50 mW (very low power) up to 500 mW (high power).

• Extensive research has been conducted at leading academic and medical institutions around the world concerning the basic underlying science of how LLLT affects mammalian tissue. For example: At the annual meeting of the American Society for Laser Medicine and Surgery in April, 2003, teams from the U.S., Canada, England, Ireland, Russia, China, Italy, Iran and Egypt presented papers on topics ranging from the effect of laser light on fibroblasts and the rheological properties of red blood cells, to the effects of LLLT on pressure ulcers, tibia fractures and snake bites. Even the U.S. Department of Defense has funded research at the Uniformed Services University in Maryland into the use of LLLT to treat wounded soldiers.

• The number of sophisticated (i.e., prospective, double-blind, randomized, placebo-controlled) clinical trials for LLLT has increased substantially. Clinical trials over the last several years have ranged from the study of LLLT to treat pain associated with carpal tunnel syndrome and soft tissue injuries to dermatological and dental applications. The quality of data collected from these clinical trials has significantly improved.

• In January, 2002, the FDA changed the device classification on LLLT devices to be classified as a “non-significant risk”, greatly streamlining the FDA clearance process. As a result, the number of LLLT devices cleared for the treatment of various medical conditions has increased dramatically.

HOW LLLT WORKS

In mammal tissue, photobiostimulation results in an apparent increase in the cellular metabolic rate and stimulation of the immune, lymphatic and vascular systems -- all of which expedite cell repair. The net result, as observed in clinical trials to date, is a reduction in pain, inflammation, edema and an overall reduction in healing time. The sooner LLLT is applied to the affected area, the faster results appear to be achieved. Also, the effects of LLLT have been proven to be greater in compromised or damaged cells. Exactly how LLLT effects mammal tissue is still a subject of considerable investigation within the scientific community. But with an ever-increasing number of peer-reviewed papers published, the basic metabolic pathways and mechanism of action of LLLT are becoming well understood. In laboratory research and clinical applications, LLLT has produced the following physiological effects:

• Intracellular chromophores (including endogenous porphyrins, mitochondrial and membranal cytochromes, and flavoproteins – which are all photosensitizers) absorb electromagnetic radiation in the IR range and transfer it to nearby oxygen molecules, thus producing reactive oxygen species (ROS) and antioxidants. At very low concentrations, ROS have strong stimulatory effects on cellular metabolic pathways.
• Stimulates ATP production within mitochondria, elevating overall cellular metabolism.
• Increases RNA and DNA synthesis, which promotes cell proliferation. This helps damaged cells be replaced more promptly, which reduces healing time.
• Stimulates Superoxide Dysmutase (“SOD”) production. SOD is an enzyme that breaks down free radicals, which can be a cause of muscle pain.
• Increases vascularity by increasing the formation of new capillaries and repairing damaged ones. The resulting increase in blood circulation promotes localized healing.
• Stimulates cell proliferation and motility (ability to move under their own power).
• Stimulates fibroblast formation. Fibroblasts are present in connective tissue and give rise to precursor cells, which form the fibrous, binding and supporting tissues like collagen and glycoprotein.
• Stimulates the production of collagen, which is the most common protein found in the body. It is essential for the repair of damaged tissue and for replacing old tissue. Collagen is the substance that holds cells together, in particular the fibers of tendons, ligaments and the fascia. Also, by increasing collagen production less scar tissue is formed at the damaged site.
• Stimulates tissue granulation and connective tissue projects, which are part of the healing process of wounds, ulcers or inflamed tissue.
• Stimulates leukocyte production. Leukocytes, or white blood cells, are involved in defending the body against infective organisms and foreign substances.
• Stimulates macrophages and phagocytosis. Macrophages are large white blood cells that engulf and destroy (phagocytosis) microorganisms, cellular debris and other foreign matter. Macrophages are involved in cell-mediated immune responses. They are drawn to inflamed areas and are particularly important in the body’s defense against infection.
• Stimulates the release of endorphins, enkephalins, and dynorphins - which are the body’s natural pain fighting chemicals.
• Reduces the excitability of nervous tissue, thus reducing the sensory transmission of pain.
• Accelerates lymphatic system activity. Edema, which is the swelling process of the body, has two basic components. The first component is liquid, which can be evacuated by the cardiovascular system. The second is comprised of proteins, which have to be evacuated by the lymphatic system. Research has shown that the lymph vessel diameter and the flow of the lymph system can be doubled with the use of low-level laser therapy. The venous diameter and the arterial diameters can also be increased. This means that both edema components (liquid and protein) can be evacuated at a much faster rate - to relieve inflammation.
• Inhibits prostaglandins’ physiological effects on tissue, which effects vasodilation, edema, and stimulated intestinal and bronchial smooth muscle.
• Stimulates serotonin release. Serotonin is an endorphin precursor, and is also associated with the relief and resolution of inflammation. The net result of properly administered LLLT can be significant reductions in pain and inflammation accompanied by accelerated healing times.

LLLT EXAMPLE: ACUTE SOFT TISSUE TRAUMA

LLLT can be used in conjunction with the majority of traditional medicines, including narcotics, opiates, anticonvulsants and antidepressants; however, cortisone steroids may negate LLLT’s immune enhancement. LLLT can also be used in conjunction with other forms of energy therapy such as ultrasound, TENS therapy and electrical stimulation.

LLLT EXAMPLE: TREATMENT OF CHRONIC PAIN

Traditional methods for pain management include over-the-counter and prescription medications, physical therapy, TENS therapy (the application of electrical impulses to the skin), psychological therapy and nerve blocking (injections that provide temporary relief). More aggressive options include neuromodulation (the implantation of devices that utilize electrical impulses to control chronic pain), implantable drug pumps and alternative therapies such as acupuncture. LLLT has the potential to replace many of these therapies for the treatment of pain, particularly chronic and acute spine and joint pain, for several reasons: