“I had to withdraw from the Rogers Masters in Montréal due to a severe abdominal muscle strain. For the next two weeks, I had two laser treatments per day with the Theralase 1000 cluster laser, which accelerated the tissue healing and reduced the pain. In the next two tournaments I was runner-up at the Western & Southern Financial Group Masters at Cincinnati and I then clinched the Pilot Pen Tennis at New Haven. Theralase laser treatments were very helpful in accelerating my recovery time.”
James Blake
Ranked #14 professional tennis player in the world (2007)
Laser Theory
The word "laser" stands for "light amplification by stimulated emission of radiation."
Lasers are possible because of the way light interacts with electrons. Electrons exist at specific energy levels or states characteristic of that particular atom or molecule. The energy levels can be imagined as rings or orbits around a nucleus. Electrons in outer rings are at higher energy levels compared to those in the inner rings. Electrons can be bumped up to higher energy levels by the injection of energy-for example, by a flash of light. When an electron drops from an outer to an inner level, "excess" energy is given off as light.
The wavelength or color of the emitted light is precisely related to the amount of energy released. Depending on the particular lasing material being used, specific wavelengths of light are absorbed (to energize or excite the electrons) and specific wavelengths are emitted (when the electrons fall back to their initial level).
The First Laser
The ruby laser was the first laser invented in 1960. Ruby is an aluminum oxide crystal in which some of the aluminum atoms have been replaced with chromium atoms. Chromium gives ruby its characteristic red color and is responsible for the lasing behavior of the crystal. Chromium atoms absorb green and blue light and emit or reflect only red light.
For a ruby laser, a crystal of ruby is formed into a cylinder. A fully reflecting mirror is placed on one end and a partially reflecting mirror on the other. A high-intensity lamp is spiraled around the ruby cylinder to provide a flash of white light that triggers the laser action. The green and blue wavelengths in the flash excite electrons in the chromium atoms to a higher energy level. Upon returning to their normal state, the electrons emit their characteristic ruby-red light. The mirrors reflect some of this light back and forth inside the ruby crystal, stimulating other excited chromium atoms to produce more red light until the light pulse builds up to high power and drains the energy stored in the crystal.
The laser flash that escapes through the partially reflecting mirror lasts for only about 300 millionths of a second-but very intense. Early lasers could produce peak powers of some ten thousand watts. Modern lasers can produce pulses that are billions of times more powerful.
Another characteristic of laser light is that it is coherent. That is, the emitted light waves are in phase with one another and are so nearly parallel that they can travel for long distances without spreading. (In contrast, incoherent light from a light bulb diffuses in all directions.) Coherence means that laser light can be focused with great precision.
Many different materials can be used as lasers. Some, like the ruby laser, emit short pulses of laser light. Helium-neon gas lasers or liquid dye lasers, on the other hand, emit a continuous beam of light.
How does a therapeutic laser system work?
Laser therapy has been increasingly used in medicine over the last few years as a non surgical means of effecting cures for a variety of pains and ailments, for assisting normal healing processes to occur earlier and better, and as prophylaxis against the occurrence of undesirable side effects. Let us look concisely at what laser therapy is, how it works, and why it is used.
Light energy consists of small packets of energy, called photons, which travel in a wave-like pattern. The number, or density, of photons in a beam of light energy, combined with the wavelength, or colour, of the light will determine what reaction will occur when the energy is incident on tissue. When incident photon densities are not high enough to cause any rise in tissue temperature, the energy is transferred directly to the target cells, which changes their level of activity. It only takes one photon, in theory, to achieve a photoresponse in a target cell. The wavelength of the laser energy will determine how deeply the beam penetrates: infrared lasers have the best penetration, thus achieving deeper absorption which is of great importance in treating muscle and joint pain types. Depending on the condition of the cells and their surrounding tissue the reaction may be photoactivation, such as induced wound healing, or photo retardation, such as the slowing down of pain transmission to give pain attenuation. These opposite sides of the same therapeutic coin are collectively referred to as photoactivation or photomodulation.
In laser surgery, the level of laser-tissue reaction is higher than the survival threshold of the target cells, and the target cells are damaged or destroyed. In laser therapy, on the other hand, the level of reaction is lower than the survival threshold, and the cells are activated. Thus a common term seen in reports is low level laser therapy, or LLLT. All our tissues consist of cells, and so all tissues are potential targets for laser therapy, from skin to bone. The energized cells communicate with each other, and with non-irradiated cells, through increased levels of intra- and extracellular chemicals. If the cells are in a normal condition, then the level of activity remains higher for a short period, and then drops down to normal. Even in a ‘normal’ patient, an almost immediate flood of endorphins, our body’s naturally-occurring opiate, occurs after laser therapy, but as they are not required for any specific pain control mechanism, they are quickly dispersed throughout the body, and naturally disappear. In other words, laser therapy assists the natural healing processes of the body: if there is a need for these processes, such as in the relief of a painful condition, or repair of damaged tissues, then the normal healing mechanisms occur more efficiently. ‘Normalization’ is the keystone of laser therapy, and so LLLT can be used to remove pain or to cure numbness; to remove abnormal colour from, or restore pigment to depigmented skin; to increase blood flow in blood-starved tissues, or decrease blood flow in certain birthmarks such as ‘strawberry marks’; and to control both hypotension and essential hypertension. Just as some patients do not respond to a particular medication but will respond to a different one, so some patients will not respond to LLLT, or will respond poorly. Similarly, some patients need a combination of medications: thus some patients will need LLLT used in combination with other therapeutic modalities. From a study of the many papers on LLLT published in the international medical literature, we can confidently say in pain attenuation, for example, which is the largest application of LLLT, we can guarantee more than 76% pain relief in over 80% of patients. Laser therapy is not a magic wand!
What is Laser Therapy?
Lasers have been used in surgery since the early 1960’s following the development of the first successful laser in 1960. Ophthalmology and then dermatology were the first medical specialties to use the intense photon density of the pure beam of laser energy to induce photothermal effects which were capable of welding detached retinae, selectively coagulating small blood vessels on the retina, and removing abnormally coloured cutaneous lesions without damaging surrounding normal tissues. This was the birth of laser surgery.
In 1968 a Hungarian clinician and scientist, Professor Endré Mester, published a paper on a nonsurgical application of laser, the induced healing in weeks of non-healing leg ulcers, some of which had a history of years of unsuccessful conventional therapies. This was the birth of laser therapy.
Laser therapy is the application of low incident levels of laser energy to achieve an ever-increasing number of clinical indications. These include: pain attenuation in a large variety of acute and chronic pain entities including pain related to abnormalities in the nerves, soft tissue, muscles, tendons, joints and bone; improved wound healing in soft tissues, tendons and bone including the induction of healing in slow-to-heal or non-healing wounds; improved local and systemic blood circulation, very useful in blood-related conditions such as Buerger’s and Raynaud’s diseases and torpid leg ulcers; increased lymphatic circulation and drainage which improves the early inflammation and swelling associated with acute injuries; enhanced autoimmune response in immune-deficient conditions such as psoriasis, rheumatoid arthritis and atopic dermatitis; and in more specific indications such as the control of hypertension and the restoration of normal pigment in selected abnormally coloured cutaneous lesions.
Laser therapy is delivered using dedicated systems, designed to produce optimum levels of laser energy at specific wavelengths to achieve the desired therapeutic effect in complete safety. These systems should be compact enough to be easily portable; rugged enough to withstand extended use in and out of the treatment room; and reliable enough to preclude constant technical problems while being easily maintained.
Why use it?
Laser surgery systems are very efficient and have well-documented applications, but are extremely expensive and physically take up a great deal of space. This expense adds to the financial burden of both the medical institution carrying out the laser surgery and the patient undergoing it. In almost all cases, the patient must come to where the laser is, due to the aseptic needs associated with surgery and the electrical connection requirements of laser surgical equipment. Well-designed laser therapy systems on the other hand require a normal mains supply. Many LLLT systems offer a fully portable, battery-powered option allowing the laser to be taken where it is needed, easily and simply. This is a boon for trained laser therapists working in rural areas or developing countries. LLLT systems are comparatively inexpensive, but have a wide range of applications, thus helping to bring about a reduction in the never-ending upward spiral of health care costs to both institutions and patients. Although the end result is very often equally good, LLLT has been proved to work more quickly and at an earlier stage than conventional surgery or therapy, thus, amongst other advantages, dramatically reducing bed time in acute injuries, the period of incapacitation in ambulatory patients, and analgesic requirements post-surgery. All of these point to potential savings for institutions and better health care for patients at lower costs. The reports in the literature on the clinical applications of LLLT all agree that laser therapy, in appropriate situations and delivered by fully-trained professionals, is efficient and safe. Although the systems are still lasers and must therefore be used safely and by trained therapists, laser therapy is totally noninvasive. It can additionally be applied interstitially in certain cases, or through flexible endoscopes to reach the articular aspects of affected joints. LLLT is usually painless, and in more than 35 years of application has been serious side-effect free. LLLT is well-tolerated by all ages and conditions of patients and in a large variety of specialties from neurosurgery and dentistry to podiatry. As each year passes, more and more applications are being presented in which LLLT is not only appropriate, but is better than conventional methods. Hand in hand with the clinical reports, advances in scientific research are elucidating the pathways and mechanisms by which laser therapy works, thereby firmly establishing LLLT as the medical tool of tomorrow, but available today.
A therapeutic laser system is athermic (no heat), with no appreciable heat transfer to the tissue. (< 0.65 degree Celsius) An athermic laser system, therefore, is not able to cause tissue damage as tissue damage arises only through thermal actions.
Thermic lasers, on the other hand, are used for invasive surgery as they cut, burn or vaporize tissue to achieve tissue removal.
Therapeutic lasers utilise a wavelength of monochromatic light in the 630 to 905 nanometer (nm) range, known as the “therapeutic window”. A wavelength of 905 nm has the least absorption in this “therapeutic window”, due to the primary influence of melanin. In the 630 to 905 nm range, the 905 nm wavelength is absorbed least by the skin and hence provides the greatest penetration of photons into the underlying tissues. It is this principle which creates the ability to “inject” photons of energy harmlessly into tissue, “energising” or “bio stimulating” this tissue into an accelerated rate of healing.
The tissue effect of lasers can best be characterized by understanding the absorption of light in tissue. The three main components of tissue that affect the absorption of light are water, haemoglobin (pigment that renders blood red) and melanin (pigment that gives skin its natural color). The absorption curves for these three substances versus the laser wavelength will determine the precise impact that a particular laser will have on tissue.
The purpose of a low level laser is to stimulate. The lower energy levels and the unfocused light beam do not impart large amounts of energy. They do provide enough energy to excite the mitochondria and cause it to undertake big-chemical reactions.
The mitochondria once stimulated by the application and infusion of light energy, produces enzymes and ATP. Cells communicate and operate using chemical signals - enzymes. Low level laser therapy is safe because cells have a natural ability to resist over-stimulation. It is not possible to harm tissue by overdosing.
Serotonin is a neurotransmitter that is used as a marker chemical for low level laser therapy. A patient who receives this type of therapy will, within 24 hours, test positive for increased serotonin by-products in their urine (Walker, Neuroscience Letters). The amount of 5- hydroxyindoleactic acid, the serotonin byproduct, is disproportionately large in comparison to the amount of energy put into the system by the treatment.
The photoactivation of enzymes used provides a huge amplification factor for initiating a biological response using light energy. (Smith, The Photobiological Basis of LLLT). The measurable effects of LLLT appear in calcium ion channels, RNA and DNA at the cellular level, and the production of proteins, fibroblasts, Iymphocytes and leukocytes (Basford, The Orthopedics Journal).
There is a well-documented inter-cellular communication phenomena of "enzyme cascading." Once cells are stimulated to produce an enzyme with the LLLT laser, the adjacent cells are stimulated by the presence of the newly produced enzymes to also produce the same chemical, effectively duplicating and enlarging the effects of light stimulation.
All of the enzymes produced are those naturally used and produced by the cell. They are produced in the ratios and quantities normally used by the body, and the result is a natural healing process. The major difference between a laser and a powerful normal light is the laser beam’s ability to travel long distances without being dispersed. This is known as coherence, and it enables the laser to focus its power very specifically. This source of light has been shown to have a strong therapeutic effect. The Theralase therapeutic lasers do not produce heat or cut like industrial lasers or powerful surgical lasers. At specific wavelengths, a Theralase laser can have profound beneficial effects on the functioning of human cells – the “building blocks” of all the body systems and body tissue (bone, skin, muscle, etc.)
The energy produced by a Theralase laser can be directed at damaged tissue cells, and by giving the cell a massive energy boost, helps to speed up the healing process. Lasers have been shown to improve the repair of tissues, from injuries such as muscle strains/sprains, ligament and tendon injuries, open wounds and bone injuries including fractures and joint dysfunction.
Tissue Interaction
There are four main effects of Low Level Laser Therapy (LLLT) specifically: wound healing, anti-inflammation, antalgic (anti-pain) and immunoregulation.
Wound Healing
The natural healing of a wound can be divided into 3 phases: the inflammation, the proliferation and the remodelling. LLLT assists in all 3 areas by increasing the fibroblasts (fibroblasts are the building blocks of collagen, which is predominant in wound healing), speeding up angiogenesis which causes temporary vasodilation (diameter of the blood vessels increases) and by speeding up the reabsorption of a haematoma (swollen area). LLLT is also very useful for burns by stimulating the enzyme superoxide-dismutase, which inhibits the peroxidation of unsaturated fatty acids (burns).
Anti-Inflammation
LLLT has an anti-oedemic effect as it causes vasodilation, but also because it activates the lymphatic drainage system (drains swollen areas).
Anti-Pain (Antalgic)
Due to less inflammation, there is less of an oedema and thus less pain. LLLT stimulates the vasodilation and lymphatic drainage, which increases the reabsorption of pain-causing products. LLLT regulates the sodium-potassium pump (this pump maintains the potential across the membrane of a nerve cell, which leads to pain transmission signals) and thus removes the transmission of pain signals from this area.
Immunoregulation
LLLT has a direct effect on our immunity status by stimulation of immunoglobines and lymphocytes. LLLT is absorbed by chromophores (molecule enzymes) that are specifically sensitive for and are activated by laser light. The enzyme flavomononucleotide is activated by 905 nm laser light and starts the production of adenosine-tri-phosphate (ATP) which is the basic energy source for all chemical reactions in our cells.
Trigger Points and Acupressure Points
Therapeutic lasers can stimulate muscle trigger points and acupressure points non-invasively providing muscular-skeletal pain relief.