By Jeffrey Tucker, DC, DACRB
Therapeutic lasers are used for three primary indications: eliminating pain, reducing inflammation and accelerating tissue healing. There are different types of light forces such as LED’s, low powered lasers and high powered lasers or “super-pulsed” lasers.
I have more than five years of experience using a Class IV laser and, more recently, decided to add the Class IIIB in my practice. My choice to add a Class IIIB laser had to do with the depth of penetration and the ability to use laser without having to move the handle around on the patient’s dermis without fear of it getting too hot and burning the patient.
We are all familiar with going to the market, buying a light bulb, usually anywhere from 25 to 100 Watts. We’ve placed that bulb in the socket and felt the heat it generates. I’m sure your fingers have experienced the burn by that heat. Laser light is a type and source of energy that can generate heat. The light must be absorbed in order for a photo chemical reaction to take place. For my practice, I need a device that can penetrate this light source deep into the hips, shoulders, knees, low back, etc. The Class IIIB is able to penetrate four inches of tissue, whereas other light products with the low powered LED do not have the power in order to penetrate sufficient depth of tissue. If you are dealing with more acute injuries or superficial injuries, these systems would be fine, but if you are dealing with deeper tissues or more chronic conditions, you are going to need more powerful systems.
There are two methodologies used to increase power. One is the Watts. There are lasers that use a “super-pulsed” technology with a very high impulse function of 50 Watts across the laser diode. Remember what a 50 Watt light bulb would feel like on your fingers once it’s in the socket! So, for a fraction of a second there is 50 Watts of power at that tissue surface. This “super-pulsed” function is what allows the practitioner to hold the handle of the laser in one place without a hot burning sensation and for the light to penetrate up to four inches into tissues. We cannot leave 50 Watts of continuous power on the same spot of tissue because it would burn a hole through the patient. The “super-pulsed” delivery method provides an average power of 100 mWatts. The maximum permissible tissue exposure is 500 mW depending on the wavelength.
The second important method to increase power is getting light of the right color. Photochemists typically work in only a few sections of the electromagnetic spectrum. Some of the most widely used sections, and their wavelengths, are the following: Ultraviolet: 100–400nm; Visible Light: 400–700nm; Near infrared: 700–2500nm.
The class IV laser companies try to increase the power because they feel that more power is better. They are right up to a certain extent, once they go above 500 mWatt (half of watt), they now exceed the maximum tissue exposure and the Class IV lasers will deliver heat to tissues which is why they have to defocus the beams or use the roller tract ball at the end of the laser handle. The advantage of a roller ball or tract ball is that you can perform fascial release during the laser treatment. Again, the disadvantage to the class IV laser is that the practitioner has to keep the light moving otherwise if they hold it in one place it will burn the patient. The important thing about how lasers work is to get the right light wavelength down into the tissues.
All lasers (class I, class III, class IV), are tools that emit light and work on the ATP pathway. It is the emitted light from the laser that produces photochemistry and therefore photobiology. For the basic functions of the body (metabolism), we need food and we have to have oxygen, water and glucose. The glucose or the sugar molecule goes into the cell and gets transported into the mitochondria. Between the inner and outer membrane of the cell, the glucose molecule is transformed through a process called phosphorylation, which is known as Adenosine tri-phosphate which gets converted to the basic energy source of cells called ATP. The last source of the Krebs cycle or the citric acid cycle forms ADP to ATP and involves a Cytochrome which is a light sensitive protein. Our eyes see from 400 to 700 nanometers of light. At four hundred nanometers (400nm), we see violet, then blue, green, orange and yellow. Red is the widest bandwidth, the peak is at 660nm.
Lasers also use two other pathways to help the healing process. One is the nitric oxide pathway. Nitric oxide is a very powerful molecule but it has a very short term life. It causes endothelial cells to relax or become flaccid which causes temporary vasodilation in capillaries. Vasodilation causes more blood, more oxygen and more fuel molecules to the tissues and kicks off the lymphatic system to drain off more interstitial fluids. Some molecules are too big to go through the circulatory system and need to go through the lymphatic system. The nitric oxide causes the lymphatic system to become more leaky and allow more absorption of interstitial fluids. You can take a person with osteoarthritic knees or an inflamed knee and measure the circumference of the knee with a cloth tape measure. After you laser them for 10 to 15 minutes, including the lateral and medial joint lines, you will see a reduction in the measurement of the knee circumference. The lymphatic system is a very important system for the body. It drains fluid, swelling and facilitates the natural fluid flow in order to be healthy. By activating both the cardiovascular system and the lymphatic system you can affect healing at a much faster rate.
The most common reason patients seek our professional help is because of pain. No matter how hard I try to create a practice with patients coming in for diet, nutrition and exercise therapy, I am still known for helping people get out of pain, especially chronic pain. I have a lot of first hand experience using laser to help many people go on their happy way after seeking help and not getting full satisfaction from acupuncture, physical therapy, drug therapy,and surgery. Pain is a biochemical process and laser helps relieve pain.
A nerve cell receives a stimulus of pain, trauma, heat, cold or whatever type. The receptors force sodium outside of the cell wall and create a potential difference of 80 milli-Volt. When the sodium is outside, its very hard for it reintegrate back into the nerve cells. It has to go through a sodium- potassium pump. The peak absorption of lipids is 900 nanometers, so if you look at the lipid membrane of a cell it’s a bi-lipid membrane. By using 905nm light with the “super-pulse” technology we can make the lipid membrane more porous and allow faster integration into nearby channels. This promotes removal of noxious pain chemicals when patients are treated. After a laser treatment the patient will say my injury “feels different,” “my pain is less,” “it dropped from an 8 to a 4 out of 10,” “it feels like I have greater range of motion.” Why? Because we have rebalanced the sodium potassium, we produce a lot of nitric oxide and we took away the inflammation and accelerated the tissue healing by ATP.
I have been impressed with the many conditions that laser can affect: TMJ, traumatic brain injuries, neck pain, shoulder pain, low back pain, knee osteoarthritis, rheumatoid arthritis, epicondylitis, iliotibial band, chondromalacia patella, plantar fasciitis, achilles tendinitis and muscle stiffness. There are hundreds if not thousands of conditions to treat but only a few contraindications of laser light.
Because laser light is so powerful, on a square inch basis, it is 100 times more powerful than the sun. This light would be damaging to the eyes. We make sure we wear special glasses and don’t point laser into the eyes. If the light goes into the optical path, the cornea of the lens focuses 30,000 times onto the retina and you would cause permanent damage to the retina if it was a sustained dose. Luckily, we have a blink reflex, but having laser into the eye is one of the main contraindications. If you are working around the periphery of the face, you have to wear glasses. If they are face down on a table and I am working on the back, I ask them to close there eyes, and in this case they don’t need to have laser glasses. Another contraindication is cancer. We do not treat somebody who has cancer if they have not been clear for five years. We are also cautious not to treat the abdomen of a pregnant woman.
Laser is effective for nerve action growth, wound healing, damage to nerves either through surgery or trauma, diabetic ulcers, diabetic polyneuropathy, venous stasis, improving oxygenation and myofascial pain. Laser is noninvasive, has little known side-effects and is safe. In conjunction with exercise therapy, nutrition and our hands-on skills, it is a highly effective treatment. Compared to drugs like NSAIDs and Cox 2 inhibitors, there are no contraindications.