First, I may be a bit particular about terminology as there are many misperceptions and misrepresentations. Due to years of inferior products and exaggerated claims, we must be specific and accurate with our statements. So this is not a discussion of “Light” therapy. This is “Laser” therapy. More specifically, we are talking mainly about “high power Laser therapy”. Although “cold” lasers or “low level lasers” work on the same principles, they often do not have enough power to elicit a measurable or consistent clinical response in deep musculoskeletal conditions. Newer high-powered Class IV therapy lasers were just FDA cleared in the US in 2005. Their use has grown dramatically in the last two years.
The basics: The two key parameters that dictate the function or capability of any Laser are wavelength and power. Laser therapy works by a wavelength-specific form of photobiomodulation. Laser light in the red and near-infrared range is absorbed by specific chromophores in the body (cytochrome C oxidase/hemoglobin/water) and this has a positive effect on specific biological reactions. This photochemical reaction increases blood flow to tissue, stimulates the release of 02 from the hemoglobin delivered, and enhances the conversion of O2 to useful energy by cytochrome C oxidase in the production of ATP. This leads to improved cellular function and/or an increase in cell growth replication, repair, or production of beneficial biochemical compounds – enzymes, proteins, immunoglobulins, DNA/RNA. There are other physiologic responses to Laser light: A mild photothermal effect (with Class IV Lasers only!) helps with vasodilation, muscle relaxation, and nerve conduction. The photo-energetic effect can stimulate acupuncture points, and the photoelectrical effect can affect membrane-bound ion channels as well as induce changes in the intracellular and extracellular ion gradients. The clinical results of these cellular reactions are:
-Accelerated tissue repair and growth
-Faster wound healing
-Improved lympathic drainage
-Improved nerve function, axonal regeneration, neurologic repair
-Trigger Point modulation
Laser power is the rate at which the Laser energy is delivered. Although seemingly straightforward, the power question seems to raise the most discussion regarding appropriate parameters. The physics associated with laser penetration within non-pigmented tissue is well established and quantified by the rate of decay of an incident beam as it moves through tissue. It can be approximated by the “optical penetration” depth of a given wavelength – the distance into tissue to which photons of that wavelength will travel where the incident beam is decreased by 63%. The power argument is almost exclusively associated with therapeutic Lasers; all other types—surgical, aesthetic, dental, and industrial –follow the basic science and physics when determining proper power guidelines for use.
Classification of all Lasers is dictated by the FDA, based on the maximum power the Laser can deliver. It is used for guidance when discussing safety and the potential to cause harm/damage, especially to the eye. Most therapeutic lasers are class IIIa, IIIb, or IV. Class IIIb lasers produce
<500 mW of power ( ½ watt). Class IV Lasers are anything over 500mW of power. Class IV therapy Lasers are extremely safe. The main benefit of higher power is the ability to deliver enough photons at the surface (a larger total dose) to compensate for the power loss (decreased number of photons) reaching deeper tissues. This allows for a more direct photochemical response on these tissues. That is why there is a much more dramatic and consistent response to class IV Laser therapy vs. class III Lasers or LEDs (Light Emmitting Diodes). Lower dosages are used when treating superficial wounds/lesions and for acupuncture point or trigger point stimulation. Adjustable power output can make a Class IV Laser effective for superficial dermatologic lesions, deep musculoskeletal conditions…and anywhere in between!
Laser therapy has broad clinical applications for pain management, wound healing, reducing inflammation/swelling/edema, and rehab in both large and small animals. Measurable positive results can be seen consistently in the following conditions:
-Arthritis/DJD (Hip dysplasia)
-Muscle, ligament, and tendon injuries (Sprains, strains, and tears)
-Ulcerations and open wounds (Lick granulomas, Hot Spots, Abscesses)
-Acute and Chronic Ear Problems
-Post Surgical pain/healing/rehab
-Neck and Back Pain (Acute and chronic)
-Even some respirator, urinary, and GI conditions.
Notwithstanding years of research on the bio-stimulatory effects of Laser light, we are just starting to realize all the clinical applications. Exciting new possibilities include help with OCD (osteochondrosis desicans), chronic rhinitis/bronchitis, insect/snake bites, allergic reactions, chronic intestinal or urinary tract inflammation, bacterial/viral infections, and adjunct therapy to improve stem cell results and even potentially for the control/palliation of some tumors. There is optimism for neurologic trauma including concussions, brain ischemia and stroke, peripheral nerve damage, IVDD, and stenosis.
It’s worth emphasizing that Laser therapy does not just accelerate healing; it actually improves repair, regeneration and remodeling of tissue. Post-op complications are reduced. Muscle atrophy can be reversed. Type 1 collagen production yields better tendon and ligament strength and elasticity. There is a positive effect on neurologic function and axonal sprouting. The joint capsule, synovial lining/fluid, and cartilage all benefit. Therefore ROM, function, flexibility and mobility are all enhanced. The potential for re-injury is greatly reduced. Performance animals not only recover quicker but they can regain their competitive edge. Pets can get back to their daily routines and become an active member of the family again. These are exciting times. Like all technology, Lasers have become smaller, safer, more efficient and easier to use. Their broad range of applications makes them not just affordable but profitable –especially when treatments are delegated to the support staff. It’s no wonder that therapeutic Lasers are rapidly becoming an indispensable tool in our clinic.
Before Laser Therapy
One Week After Laser Therapy
Dr. Alan Schulman is a renowned Board Certified Veterinary Surgeon. While he is particularly known for his orthopedic, neurologic, and reconstructive surgical expertise, he...+ Learn More
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