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.