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Medical Wellness Archives

Clinical Trial on Laser Therapy as a Pain Control Modality

2005: Volume 2, Number 2

Bruce Gundersen, DC, FACO



Reduction in the perception of pain can be achieved with specific applications of Low Level Laser Therapy (LLLT) at 830 nm for certain conditions.

The study is a pilot project and was not considered by a review board (IRB) for the initial phase. Continued investigation is suggested. The equipment for the study was provided by MicroLite. No fees for treatment were charged to any patients and no subjects were paid to participate in the study.


There are few studies on LLLT and those that exist rarely distinguish between the various wavelength devices. According to the Swedish Medical Laser Society Light Emitting Diode (LED) units are heating devices and seem to take around 2x the incident dose of LED to produce the effect of the Laser probe and then to a much shallower depth of penetration. Both LEDs and LASERs work, but more research must be carried out with LEDs. LLLT research should not be used to justify LED equipment, or to infer the benefits of LED therapy (this could apply equally to pulsed v continuous wave lasers). There are still no investigations showing that Light Emitting Diode Therapy (LEDT) is as good as LLLT although many comparisons have been made, also with a different dose. The depth of penetration depends primarily upon the wave-length and power density of the beam incident to the tissue, and the absorption/ reflection characteristics of the irradiated tissue.

Another key point is that LED devices are classified by the FDA with a product code ILY. The Device Description is Infrared lamp. True laser devices have a product code of NHN. The Device is a lamp, non-heating, for adjunctive use in pain therapy. The Device Description is also Infrared lamp. LED devices heat tissue and sellers of LED devices must warn customers of the hazards of heat generated by their modality, unlike low-wattage lasers that heal without heating human tissue.

The primary clinical point of the literature review is that certain light therapy seems to be a leading cause for remission of pain generation or of pain perception in both acute and chronic situations. There is also some evidence of tissue healing rate affectivity. In conclusion from analyzing these articles, LLLT is not well understood by those who have investigated the variety of frequency responses and expectations.

A trial was designed to measure the patient’s perception of pain and relative improvement on various conditions that cause pain or have pain associated with them. Patients who had reported persistent pain were notified of the project and invited to participate. Other providers of physical medicine were notified as well and encouraged to have patients with similar painful conditions inquire. All patients admitted to the study had a history of pain with multiple episodes of chiropractic manipulation and physical therapy with various degrees of limited success.

A combination Visual Analogue Pain scale and pain drawing was used to measure an intake score for each patient and document the location and type of pain. The Treatment Protocol was the same for each patient, only the location of the treatment differed based on the reported area of pain. Depending on the tissue to which the treatment was applied, three techniques were used: Rotation on thicker muscular tissue, alignment on tendons and ligaments and pivot on combination areas. There were 4 men and 7 women ranging in age between 15 and 83 years of age. Intake measurements include a visual analogue pain scale from 0 to 10 with 0 representing no pain and 10 representing the most pain. Patients with complaints of less than 6 weeks onset were considered in the acute group and those of more than 6 weeks were in the chronic group. The intake physician determined each of the following items prior to beginning any treatment: Treatment foci, the number of foci per complaint, the nature of the treatment protocol, rotational, alignment or pivot application of the laser instrument depending on the tissue being measured. Each focus was treated with 4 joules per cubic centimeter. Patients were positioned with treatment as closely horizontal to the heart as possible.

The average intake score was 7.18, and the average exit score was 2.91 on a scale of 0-10 with 0 being no pain and 10 being most pain. The average intake score of the chronic group was 6.83 and the average exit score was 3.33 showing a measured average change of 3.5 that equates to an improvement quotient of 51.2%. The average intake score of the acute group was 7.6 and the average exit score was 2.4 showing a measured average change of 5.2 that equates to an improvement quotient of 68.4%.

It is noted that every patient in the study perceived some reduction in pain. It was evident to the staff that the perception of pain was reduced in most patients after 1 or two sessions of treatment. It seemed as though the chronic group noted the most significant changes most rapidly even though their overall change was less than the acute group; but no measurements were made to corroborate this. It would be wise in a future study to have the patients complete a Visual Analogue Pain scale after each session to see when the most benefit was derived and to determine if 6 sessions were actually necessary to produce the remission of pain. It seemed that chronic patients needed less sessions to respond than did the acute group. This would be very interesting to bear out with future study as it seems to be opposite of the response to typical non-drug and non-surgery physical medicine modalities.

The 830nm cold laser treatment delivered in the protocol described above produces a consistent reduction in the perception of pain at various foci in patients with a variety of diagnoses. This may be temporary or permanent; this study could not determine any long term benefits. Follow-up and additional measurements in functionality changes are indicated to determine tissue healing, rehabilitation or recuperation as a result of this modality.
The other literature referenced herein shows a wide variety of responses. This study specifies one wavelength device and measured its effect on pain perception. It can be considered that many forms of light therapy have been studied on the surface and that an equally wide spectrum of response can be expected.


Under controlled protocol for specific pain relative to a variety of conditions, the 830nm Cold Laser device can produce a consistent remission of pain perception in both acute and chronic situations. Additional study is indicated to 1) follow-up on patients whose pain is reduced to see if there is a lasting effect; 2) measure functionality as a part of the initial considerations; and 3) measure timing of response to treatment by considering pain tools on each visit rather than just intake and exit.

1. Effects of low-power laser irradiation on cell locomotion in protozoa. Photochem Photobiology. 2004: 80 (3): 531-534.
2. Pugliese L, Medrado A, Reis S, Andrade Zde A. The influence of low-level laser therapy on biomodulation of collagen and elastic fibers. Pesqui Odontol Bras.2003; (4):307-313.
3. Medrado A, Pugliese L, Reis S, Andrade A. Influence of low level laser therapy on wound healing and its biological action upon myofibroblasts. Lasers Surg Med. 2003; 32 (3): 239-244.
4. Hopkins J, McLoda T, Seegmiller J, Baxter G, Low-Level Laser Therapy Facilitates Superficial Wound Healing in Humnas: A Triple-Blind, Sham-Controlled Study. J Athl Train. 2004:39 (3): 223-229.
5. Lizarelli R, Marcello O, Mazzetto M, Bagnato V. Low-intensity laser therapy to treat dentin hypersensitivity: comparative clinical study using different light doses. Proc. SPIE. 2000; Vol. 4422.
6. Corona S, Nascimento T, Catirse A, Lizarelli R, Dinelli W, Plama-Dibb R. Clinical evaluation of low-level laser therapy & fluoride varnich for treating cervical dential hypersensitivity. J Oral Rehabil. 2003:30 (12): 1183-9.
7. Marsilio AL, Rodrigues JR, Borges AB. Effect of the clinical application of the GaAlAs laser in the treatment of dentine hypersensitivity. J Clin Laser Med Surg. 2003; 21 (5): 291-296.
8. Kawalec J S, Hetherington J, Pfennigwerth C et al Effect of a diode laser on wound healing by using diabetic and nondiabetic mice. Journal of Foot and Ankle Surgery. 2004; 43 (4): 214-220.
9. Cho H J, Lim SC, Kim S G et al. Effect of low-level laser therapy on osteoarthropathy in rabbit. In Vivo. 2004;18 (5):585-591.
10. Irvine J, Chong S, Amirjani N, Chan K. Double-blind randomized controlled trial of low-level laser therapy in carpal tunnel syndrome. Muscle Nerve. 2004; 30 (2) :182-187.
11. Lapchak P A, Wei J, Zivin J A. Transcranial infrared laser therapy improves clinical rating scores after embolic strokes in rabbits. Stroke. 2004; 35 (8): 1985-1988.
12. Silva J, Lacava Z, Kuckelhaus S, Silva L et al. Evaluation of the use of low level laser and photo sensitizer drugs in healing. Lasers Surg Med. 2004;34 (5): 45 1-457.

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