Functions / Effects of NIR Class 4 laser therapy

Generally promoted functions:

• Increased circulation
• Immune stimulation /  Immunoregulation / Immunomodulation
• increased lymphatic drainage
• Muscle relaxation
• Improved vascular activity / vasodilation
• • Type 1 collagen production (yields better tendon and ligament strength and elasticity
• Accelerated cell reproduction / tissue repair and growth / faster wound healing
• • Neurologic repair / axonal regeneration / improved nerve function
• Increased metabolic activity
• Analgesia
• Anti-inflammatory: reducing swelling, edema
• Decreased fibrosis
• •  Acupuncture or trigger point stimulation
• •  Enhanced range of motion,  function, flexibility and mobility

 Specific infrared frequencies perform different tasks:

In addition to power level, the laser wavelength determines penetration depth  (note that wavelength is inversely proportion to its frequency)

•   650 nm - Accelerates Surface Healing.    Absorbed well by melanin in the skin. By inhibiting bacteria and promoting cell growth, it heals wounds and regulates scar tissue
• An optimal window around 790 nm penetrates the deepest - Ideal for pain management.    In this window, laser photons are least absorbed by melanin, hemoglobin and water, and therefore penetrate the deepest.
• 810 nm - Increases cellular energy production.   Allows cells'mitochondrial cytochrome oxidase enzymes to absorb photons to promote ATP cellular energy production; particularly targets damaged cells;
• 915 nm - Enhances oxygen delivery.   Stimulates hemoglobin molecule to deliver oxygen to treatment site to be used for energy production. 915 nm is  hemoglobin's peak absorption wavelength.
• 970 nm - Stimulates tissue microcirculation

Effects of laser photon beam

Primary effects

Energy from 400-1100nm wavelength photons are specifically absorbed by chromophores in the skin (including melanin, blood and water).    Chromophores convert light energy to kinetic energy in mitochondria and cell membranes of cells (E.g. fibroblasts) located up to ~4cm depth into the body.  Scattered photons from a Class 4 infrared laser produce an egg-shaped treatment area in tissue. The ability of infrared lasers to target chromophores is utilized in cosmetic therapies such as hair removal, skin resurfacing, and treating age spots, rosacea, and vascular lesions / broken blood vessels.

Secondary effects

Primary reactions precipitate a cascade of metabolic changes resulting in physiological changes to cells.    E.g. changing membrane permeability, release of calcium from mitochondria to change cell's intrarcellular levels. This in turn stimulates cell metabolism and regulates signaling pathways needed for wound repair, such as cell migration, RNA/DNA synthesis, cell mitosis, protein secretion, and cell proliferation.

Tertiary effects

Secondary events induce distant effects.   Affected /energized cells communicate with each other and non-irradiated cells via increased levels of cytokines and/or growth factors. This leads to an increased immune response to control inflammatory healing (activates T-cells, macrophages, several mast cells, and increases endorphin synthesis / decreases bradykinin to control pain)

References

Practical pain management