Excellent review of LLTL (via collagen synthesis)

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http://www.bodytuning.us/articles/AdvanceDR03.htm

Myth or Magic?

Does low-level energy laser therapy really work?

By Anne Hartley, BPHE, dipATM, CAT©, DOMP

From the beginning of time, the Egyptians, Greeks, Aztecs and Mayans worshipped the sun, believing in the curative powers of light energy.

Today, we employ low-level energy laser therapy to treat a variety of ailments, from chronic wounds to carpal tunnel syndrome to facial pain. Yet, controversy surrounds low-level energy laser therapy.

Does laser therapy really work? It does, but the research is difficult to interpret. Few properly controlled clinical trials or double-blind studies exist. Moreover, research papers cover a bewildering range of wave lengths, power and energy densities, pulse repetition rates and durations of treatment, making definitive conclusions difficult. Numerous animal studies may not have relevance to human tissues or pathologies, and no fixed protocols have been reproducible.

But we do know low-level energy laser therapy accelerates healing through collagen synthesis and increased vascularity of the healing tissue. It also reduces pain through endorphin release.

The photobiostimulation for wound healing remains the cardinal indication for low-level energy laser therapy. It is the modality of choice for trophic, varicose diabetic and decubitus ulcers, especially chronic or unresponsive skin necrosis, burns and herpes zoster. Herpes simplex and post-op wounds respond well, and remodeling of the scar tissue accelerates.

Mester documented this with research in 1965 using the helium neon laser to treat chronic skin ulcers and bedsores. He determined that the epithelium healed faster when it was irradiated with an energy of 1.0 joule per cm2.

Research from then to now indicates conclusively that laser augments the healing of cutaneous tissue. A study by Mester et al. says it all, when 1,361 patients with chronic ulcers were treated over a 25-year period with beneficial results.1 All received 4 joules/cm2 .

Evidence-based research shows that laser works effectively on musculoskeletal conditions as well, including shoulder tendinitis (bicipital and supraspinatus), rheumatoid arthritis, migraines (through auricular techniques), myofascial trigger points, cervical and lumbar pain, lateral epicondylitis (mixed findings), knee arthritis, tenosynovitis, low back and neck pain, and acute injury edema.

In addition, low-level energy laser therapy is effective on neural pathology, including trigeminal neuralgia; post hepatic neuralgia (shingles); rheumatoid arthritis; intercostal neuralgia; occipital neuralgia; carpal tunnel syndrome; and dental, radicular, pseudoradicular, neurogenic and orofacial pain. Low-level energy laser therapy is also effective on low back pain and diabetic neuropathic foot pain.

Applying Low-Level Energy Laser Therapy

Laser can be applied clinically with a probe (single diode -.2 cm diameter light), multi-diode head or scanner. The probe is more convenient for small lesion sites, while the multidiode applicators are for larger areas. The scanner is used for very large areas, such as skin pathology, and uses an indirect technique so the applicator doesn't touch the painful site.

The depth of penetration for the laser energy varies. With direct penetration, photon energy penetrates directly under the skin; with indirect effects, photon energy attenuates, scatters and disperses in the tissue.

Although several types of lasers exist, the two main ones used in therapy are infrared and helium neon, with infrared being the most common. Infrared has an indirect penetration of 5 cm and direct penetration of 1 cm. Helium neon (HeNe) has an indirect penetration of 5-15 mm (1-1.5 cm) and direct penetration of 0.5 cm.

The absorption of laser energy into the body will vary according to the melanin content of the skin (more absorption is correlated with darker skin); the hydration of the skin (dehydrated skin has less absorption); the blood content of the skin (more blood corresponds with more absorption); and the fat content (the less fat, the deeper the penetration). The absorption can vary from 20 percent to 30 percent with different skin and body types.

The physiological effects of laser energy in the body are complex. Photons are absorbed in cytochromes and porphyrins in the mitochrondria of a cell for helium neon lasers or those in the visible red light spectrum. With infrared lasers, the energy is mainly absorbed by the cell membranes.

The following is the protocol for laser use:

1. If laser treatment is indicated, determine the depth of the lesion and decide on the type of laser that can penetrate to that depth (HeNe 1 cm vs. infrared 5 cm).

2. Determine the stage of healing; acute pathology responds to biostimulation settings of 0.05 - 0.5 J/cm2, while chronic pathology responds to 0.5 - 4 J/cm2. The optimal intensity for laser has not been determined, but the research indicates that the best results occur with 4 joules/cm2.

3. The length of time for treatment will depend on the power (milliwatts) the laser emits. The greater the milliwatt power, the shorter the treatment time. For example, the 60mW laser produces 3.6 joules of energy in one minute, and the 120mW laser produces the same amount of energy in 30 seconds.

4. Three to four treatments should produce positive results with daily treatment or three times per week for 15 sessions. For wound closure, Houghton indicates that daily treatment is better than alternate days or three times per week. Her research also indicates that the 48 milliwatt laser is more effective than the 14 milliwatt laser for wound closure.2

5. When treating acupuncture or trigger points, determine the dosage per point. The " point " can be defined as an area that's 5 mm (0.25 cm2) in diameter or less. Again, the literature indicates that 1 joule per point is the preferred dose. Apply the laser probe to the acupuncture or trigger points.

6.For muscle injuries, treat the muscle directly with a multidiode laser. If pain exists, treat the spinal segment that serves the muscle with the laser probe. For tendon pathology, treat the tendon directly with the probe or multidiode pad, depending on the size of the area involved. It's also possible to treat the spinal segment, nerve trunks, and nerve roots that serve the muscle or the local acupuncture points.

7. For ligamentous injuries, joint pathology or capsular restrictions, treat the ligament or joint directly with the probe or multidiode pad, depending on size of the lesion site. Treat the spinal segment, nerve roots or nerve trunks that serve the specific joint with the probe. An example is the C5 level for the shoulder joint adhesive capsulitis.

For avulsion fractures, periosteitis, stress fractures or bony fractures, treat the nerve supply to the involved sclerotome. Or treat directly over the site with either the probe or the multidiode, depending on the size of the injury site. Trigger points, ah shi or acupuncture points can be treated with the probe to help alleviate the pain.

8. For skin pathology, decubitus ulcers, burns and wound healing, direct applications at the margins (1 cm from the edge) with the probe, or use an indirect application with the multidiode or scanner on the bed of the wound. For indirect treatment, set a grid pattern, which allows a more accurate application.

9. For general pain, determine the cause and treat the local acupuncture points and the spinal segments that supply the areas of pain. Headaches, lumbar, cervical and thoracic pain respond well to segmental treatment with the probe. Because laser is so effective on neural pain and pathology, treat the nerves directly with the probe or multidiode. Address the local acupuncture points or tender soft tissue trigger points in the area as well, such as the trigeminal nerve.

When working with patients, describe what you're attempting to achieve with the laser and get their permission to apply the modality. Give them eye goggles, and wear them yourself during the treatment. (Retinal damage can occur if laser light is shone into the eyes.) After treatment, check the skin to determine whether any immediate improvement occurred. Document your settings and patient comments. After the application, progress with the remainder of your rehabilitation program.

Low-Level Energy Laser Therapy (LLLT) Contraindications

Even though laser produces physiological benefits, it's not for everyone. It's contraindicated during pregnancy because it may interfere with normal development of the fetus. It's also contraindicated in the cancer patient because it may enhance and spread the pathology. People with epilepsy, children and those with mental disabilities and dementia aren't appropriate candidates for laser therapy.

Lasers cannot be applied over the thyroid, endocrine glands, chemical-sensitive tissue, the sympathetic ganglia, vagus nerve or the cardiac region in patients with heart disease. (Lasers may produce neurogenic responses that further stress the diseased heart.) Be cautious when applying laser to epiphyseal plates because it may affect bone growth. And take care when applying lasers over sensitive or photosensitive skin or tissue, since it can cause skin reactions. Skin reactions also can occur in the patient taking immune suppressant drugs, NSAIDs, steroidal medication, anti-inflammatants and anticoagulants.

Laser therapy can be an effective modality for a variety of cutaneous wounds and ulcers, neurological conditions, arthritis and chronic pain. To apply low-level energy laser therapy safely and effectively, we must go through a systematic protocol and review the outcomes after treatment. With the recent approval of low-level energy laser therapy in the United States, we also need to closely follow the evidence-based research to determine the optimal dosage and sites for application.

References

1. Mester, E., Mester, A.F., & Mester, A. (1985). The biomechanical effects of laser application. Lasers in Surgery and Medicine, 5, 3139.

2. Houghton, P., Brown, J., Patel, J., & Kamani, K. (1999, June). Factors affecting ability of laser to stimulate wound closure in vitro. Laser Therapy.

Anne Hartley, BPHE, dipATM, CAT©, DOMP, is a Canadian athletic therapist and osteopathic manual practitioner. She is a full-time professor in the sports injury management program at Sheridan College in Oakville, Ontario, and has lectured extensively in Canada and the United States.