When determining how to apply laser therapy for back pain there are a few key factors to consider. This is taken from my article published in Advance Physical Therapy Magazine this month.
Laser PowerPower affects penetration, dosage, and treatment time. More power offers deeper penetration, higher therapeutic dosages, and decreased treatment times. Lasers are classified by power. Class 3 ‘cold lasers’ are at maximum power output of 500mw from a single laser source. Class 4 lasers are anything over 500mw.You cannot make up for insufficient power by increasing treatment time. Depth of tissue penetration will not increase with more application time if you have insufficient power. Positive results require more than increasing time.
65% of laser energy is absorbed in the skin and subcutaneous tissue layers with the following having a high affinity for absorption:
Hemoglobin in blood
Melanin in skin, hair, moles, etc.
Water (present in all biological tissue)
In order to overcome these factors one must start with large quantities of energy to reach the deeper target cells and myofascial structures with a required dose.
Optimal Dosage
Dosage is the single most important parameter for a successful outcome in laser therapy. Too little, or too much energy produces no effect. There is an ‘Optimum Window’ of therapeutic dosage. The matter of correct dosage is very complicated, since a number of factors must be taken into account including laser wavelength, power density, type of tissue, condition of tissue, acuteness or chronicity of the problem, skin pigmentation, treatment technique, and depth of target tissue.
The primary factors in laser therapy that determine dosage is power and time. DOSAGE = Power x Time While power is the amount of energy measured at the source of the beam, dosage is the amount of energy delivered to the skin and target tissue. Dosage may also be referred to as energy density or fluence. Its unit of measure is the Joule (J). Current industry dosage application requires 1- 4 J/cm2 for superficial, and 4-10J/cm2 for deeper conditions. 3 Therefore, a 50cm2 deep tissue area may require up to 750J for maximum effect.
Optimal Wavelength
Light characteristics are determined by its placement along The Electromagnetic Spectrum. Wavelength is calculated in nanometers (nm). The ideal range for therapeutic lasers is along the Invisible Red (IR) spectrum of 790-970 nm. IR beams penetrate deeper into the body for increased effects on cellular tissue. Wavelengths in the Visible Red (VR) 600’s nm spectrum are ideal for superficial conditions and limited in deep penetration.4 Wavelengths above a 1000nm lose therapeutic value and crossover into surgical laser applications. Deep therapy applications such as spinal stenosis, disc herniations, hip derangements, trigger points of spinal intrinsic stabilizer muscles and neuropathic conditions are inherently more responsive to the Invisible Red (IR) wavelength.
Perry Nickelston, DC
www.painlasercenter.com
Tags: General by Dr. Perry
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