NIR class 4 laser therapy speeds healing and reduces pain /inflammation

LASER is an acronym for Light Amplification by Stimulated Emission of Radiation

What is NIR class 4 laser therapy?

A red/near infrared (NIR)frequency of light (~700-1000 nanometers) is applied via a class 4 laser to problem areas of the body at an appropriate dosage and power level.    SImilar to Low Level Laser Therapy (LLLT, aka cold laser therapy), this therapy is also referred to as photobiomodulation, whereby laser energy is absorbed by specific chromophores in the body:

• Melanin in skin
• Cytochrome C oxidase (to promote cellular energy production);
• Hemoglobin (to enhance oxygen delivery to cells)
• Water (to improve circulation)

The overall functional effects are:

• Improved cellular function;
• Increased cell growth;
• Repair/production of  enzymes, proteins, immunoglobulins and DNA/RNA.

In contrast to LLLT, the higher wattage utilized in class 4 laser therapy also produces a mild photothermal effect, which aids vasodilation, muscle relaxation and nerve conduction. Note that an excessive photothermal effect can damage tissue.

Infrared Class 4 laser therapy produces biomodulating reactions that can very effectively:

• Reduce pain
• Reduce inflammation
• Enhance tissue healing (in hard and soft tissues, incl. muscles, ligaments, bones)

By definition a class 4 laser must be able to deliver power of at least ½ a watt (i.e. 500 milliwatts). Unfortunately this category does not distinguish between the different power levels required for cosmetic / hair-removal use, healing, surgical lasers or even military lasers (capable of shooting down a satellite!).

• The Class 4 laser is more powerful than low level laser (or light) therapy (LLLT) devices.  This extra power enables class 4 lasers to penetrate deeper into the body to reach muscles, and areas such as spine and hip. In contrast to high powered lasers, LLLT does not produce a healing photothermal effect.   The typical power level employed in class 4 lasers used for healing is around 5-8 watts, compared to 5 milliwatts - 1/2 watt for LLLT class 3a and 3b lasers.
• Most common class 4 therapy uses a gallium-aluminum-arsenide (GaAlA) semiconductor diode to produce an infrared laser beam.    A diode may produce either a continuous wave or pulsed frequencies of 2-10,000 Hz. Infrared beams are carried by a fiber optic cable and naturally diffuse (not focussed) to a 10-12° angle to produce beam diameter sizes of 10-25mm (this produces a spot treatment area of 0.8 - 5cm²). Power densities are typically in the 0.4 - 3 W/cm² range. Primary inteactions with tissue reach a depth of ~4 centimeters; secondary and tertiary photon effects on tissue and body systems are seen at greater depths. Pulsed frequencies typically have a 50% duty cycle (meaning the pulse is active half the time between pulses).

Infrared class 4 lasers were FDA-approved in 2005 as medical therapy devices (class 3 lasers were FDA-approved in 2002):

• However, the FDA consider them only as an infrared heating lamp.   The FDA does not recognize the bio-stimulatory effects of the laser; interestingly,  Europe has been researching and recognizing the benefits of using lasers for therapy for over 3 decades;
• Infrared class 4 lasers are prescription medical devices available for sale and use only to health professionals.  These are then trained by the manufacturer in their use. The U.S. has many class 4 laser therapy providers across the country.  Treatment cost (~$50 -75 / treatment) is not usually covered by insurance.

Some class 4 lasers
	Brand	Specs. (CW=continuous wave)	Cost
	K-laser (still available, but no longer produced).	K-800.  0.1 - 8 watts K-1200.   0.1 - 12 watts CUBE-4.   0.1 - 15.0 watts (CW) & 20 watts peak / av. 12 watts pulse
	Summus lasers (K-laser rebranded in 2019)	P-4.  0.5-24 watts in continuous mode or 28 watts peak / av. 15 watts pulse.         4 wavelengths (650nm, 810nm, 915nm and 980nm); P-3.   Up to 18 watts;  3 wavelengths (650nm, 810nm, 915nm), H1.  15 watts; 3 wavelengths (650nm, 810nm, 915nm); 1-20,000Hz pulse;         Lenses: 50mm broadbeam, 25mm zoom
	Eltech Klaser Cube 4 plus by Chattanooga (Made in Italy	12-15 watts 4 wavelengths (660nm, 800nm, 905nm, 970 nm) Intense Super Pulse (ISP) & CW	~$20-28k
	EVOlaser	9 - 20 watts  Up to 4 Wavelengths  Pulse & CW	~$10-15k
	Pilot Laser	9 watts 810nm Pulse & CW	~$8k
	Apollo Laser	.5 - 5 watt 810nm CW	$5k and up

Conditions helped by NIR Class 4 laser therapy

The high-power of the class 4 laser enables it to penetrate deep enough into the body to reach muscles, and areas such as spine and hip

Some examples of health problems healed by class 4 laser treatments:

• Fibromyalgia
• Peripheral Neuropathy; neuromuscular disease / damage
• Plantar fasciitis
• Acute muscle, ligament and tendon injuries.   E.g. strains, sprains, tears, rotator cuff and shoulder injuries
• Repetitive-use injuries,   E.g. carpal tunnel syndrome
• Arthritis (benefits joint capsule, synovial lining and fluid, and cartilage), hip dysplasia (Degenerative Joint Disease)
• Chronic frozen shoulder, shoulder tendonitis
• Reversal of muscle atrophy
• Ulcerations, open wounds (abscesses)
• Trauma / fractures
• Acute / chronic neck and back pain
• Some respiratory, urinary and GI conditions

How to obtain class 4 laser treatment

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)

• 650nm - 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)

Class 4 laser treatment is obtained at clinics

You can search the web to find a provider near you.

How many treatments required?

Depends on type of condition:

• Acute conditions.   Can be treated more frequently and require fewer visits - typically 4-6 treatments
• Chronic conditions.   Typically require 10-15 visits over 2-4 weeks. Treatments can be 2-3 times / week for short duration, or 1-2 treatments / week with longer times

The effects of class 4 laser treatments are cumulative.

Pain relief is typically achieved before healing occurs.   It is therefore necessary to stay with the therapy if you want complete healing that deals with the cause of the problem

How long does each treatment take?

Treatment times are just a few minutes

Does it hurt?

Class 4 laser therapy is painless.   Although the patient may feel some slight, relaxing warmth

Cost?

Cost is around $55-75 /treatment (2019 prices)

Contraindications

The class 4 laser should not be used:

• Directly over the eyes;
• Directly over the uterus of a pregnant woman;
• Directly over a known cancerous tumor;
• Directly over thyroid tissue

Drug Interactions

One should wait at least seven days after having a cortisone (corticosteroid / steroid) shot.   Since both steroids and Class 4 laser therapy suppress prostaglandin E-2 (which otherwise has a  hormone-like effect to promote inflammation in its local area)

Light sensitive medication may be affected by laser therapy.

Class 4 therapy lasers are safe to use over metal implants.   Tissue warming occurs from the outside-in.

FDA and safety

A Class 4 therapy laser is used by someone trained to understand and practise safety precautions for handling this powerful device. 

The FDA requires wavelength-specific safety goggles for everyone in the treatment room to protect eyes.     SInce infrared lasers are outside the visible spectrum, the blink reflex will not register.  The Nominal Hazard Zone (NHZ) is defined as "the space within which the level of the direct, reflected, or scattered radiation during normal operation exceeds the applicable MPE."  The NHZ for Class 4 therapy lasers is about 21 feet.

The FDA also requires that one person be designated as the "Laser Safety Officer" for the treatment facility.

Treatment dosage

Dosage refers to the amount of energy per unit area of tissue surface exposed to laser beam.   Measured as Joules / cm².   The power of a laser is the rate of energy being delivered (usually measured in watts)  1 watt is 1 Joule / second, so a laser operating at 8 watts power level, with a continuous wave would deliver 480 joules in 1 minute, and 240 Joules/min in pulsed mode (with 50% duty cycle). In 1 minute, a treatment area of 50cm² (~8 inches²) would therefore receive a dose of 9.6 J/cm² (480 J /50cm²) in continuous mode, or 4.8 J/cm² in pulsed mode.

Required dosage is affected by several factors: including wavelength of beam, tissue type /condition, whether problem is acute or chronic, skin pigmentation, treatment method.

There's a "Goldilocks" dosage window.  Below this window, biostimulation does not occur, and above the window, it is inhibited or can cause damage to tissue. This has been easily observed in wound healing and hair growth (Tuner & Hobe, 2004). Biostimulation is reported in the dosage range of  0.001 to 10 J/cm^2.

• Photobiomodulation has been extensively used for many years on sports injuries, arthritic joints, neuropathic pain syndromes, back and neck pain. Over 700 randomised clinical trials have been published on photobiomodulation, half of which are on pain.
• Irradiation of in vitro rabbit articular chondrocytes with 4-6 J/cm² demonstrated substantial biostimulation compared to control cultures. (Jia & Guo, 2004)
• 13 J/cm² increased the number of chondrocytes and the thickness of the articular cartilage in immobilized rabbit knees. (Bayat et al, 2004)

When treating with a GaAlAs diode laser, the current accepted dosage for deep-lying pain is 4-10 J/cm2. (Ibid Tuner & Hode, 2004)^.

Output wattage.  A deeper target requires a higher wattage to enable sufficient photons to reach the target to yield the primary effects of photobiomodulation. Examples (adjusted by clinical laser therapist according to his or her judgement):

• 2 watts for tennis elbow (lateral epicondylitis);
• 5 watts for cervical pain ( i.e. wear and tear of cartilage / bones connected to the neck, especially spinal disks as in cervical spondylosis /osteoarthritis, mostly seen in older people)
• 7 watts for lower back (lumbar) pain.

Much of the beam energy is reflected, or scattered into none-targeted areas.   An estimate of at least half of the energy is lost when targeting an area well below the skin.

Treatment methodology

Applying a combination of continuous wave and various frequencies of pulsation is the best treatment approach. Using different pulse frequencies prevents the body from getting immune to and becoming less responsive to any steady stimulus.  (Blahnick & Rindge, 2003)

The treatment wand is kept in motion during the continuous wave phase, and is pressed into the tissues for several seconds during laser pulsation.

Empirical evidence provides a guide for which pulsation frequency ranges to use for specific problems and tissues:

• 2-10 Hz for an analgesic effect;
• Around 500 Hz is biostimulatory;
• >2,500 Hz has an anti-inflammatory effect;
• > 5,000 Hz is anti-microbial and anti-fungal. (Ibid Tuner & Hode, 2004, p 78)^.

Ideally - Class 4 laser therapy combines several of these pulsation frequencies to provide an analgesic effect, inflammation reduction, and biostimulation.

References

Practical pain management

Bayat M, Ansari A, and Hekmat H (Sep 2004) Effect of low-power helium-neon laser irradiation on 13-week immobilized articular cartilage of rabbits. Indian Journal of Experimental Biology. 42(9): 866-870.

Blahnick J and Rindge D. Laser Therapy, A Clinical Manual. 2003. Healing Light Seminars, Inc. Melbourne, FL. p 27.

 Jia YL and Guo ZY (2004) Effect of low-power He-Ne laser irradiation on rabbit articular chondrocytes in vitro. Lasers in Surgery and Medicine. 34(4): 323-328.

Moore P, Ridgeway TD, Higbee RG, Howard EW, and Lucroy MD (2002) Effect of wavelength on low intensity laser irradiation — stimulated cell proliferation in vitro. Lasers Surg Med. 36(1): 8-12.

Tuner J and Hode L (2004) The Laser Therapy Handbook. Prima Books. Grängesberg, Sweden. pp 72-74.

Dr. Mercola (www.mercola.com) interview with Dr. Phil Harrington,a chiropractic physician who was involved in the development of the K-laser