Nearly everywhere you look these days you see lasers being used for something. Lasers for microchip etching, lasers for delicate eye surgery, lasers for communication, lasers for surveillance, and even “low level” lasers for chronic pain therapy. Which begs the question,” Does low level laser therapy work for chronic pain?”
In my practice of pain management, the full time Chiropractor that worked in my practice used low level laser therapy (LLLT) as an adjunct to the manipulative therapy that he administered.The patients that obtained relief were convinced of its usefulness…but what does the medical literature say?
LLLT was first used in the 1960s by a Hungarian physician named Endre Mester. The use of LLLT has only really been popular in the U.S. since 2002, though it was extensively used in Europe and Asia for several decades before that time.
Other names for LLLT include: soft laser, cold laser, bio-stimulation laser, therapeutic laser, and laser acupuncture.
As you many have surmised, not all lasers are the same. The Food and Drug Administration (lasers are regulated by the FDA) has classified lasers as follows:
- Classes I and II: very low power lasers with little skin penetration. Examples would be laser pointers and laser scanners.
- Class IIIa: this type of laser has little penetrating ability, would also be called light-emitting diodes (LEDs), and functions similarly to a heat lamp. Some low power, self-administered LLLTs are in this category.
- Class IIIb: this type of laser would be more in keeping with what is usually considered a laser. This class of laser utilizes usually less than 600 mW of power, uses lasers with wavelengths of 632 to 904 nm (the depth of penetration is dependent upon the wavelength of light used), and does not heat the skin or underlying tissue. This is the usual category that physician administered LLLT is in.
- Class IV: these lasers operate in the 2 to 10 watt range, have powerful effects on biological tissue, and are often used in surgery or dermatology. This type of laser can heat, cut, or vaporize biologic tissue. This type of laser can reflect off mirrored surfaces, metal surfaces, and polished surfaces causing burns, fires, or biological damage to spectators (especially to the retina).
How Does Low Level Laser Therapy (LLLT) Work?
LLLT works by energizing biological tissue without heating it, creating sound, or creating vibration. It does not cut, burn, or vaporize biological tissue.
In this way, it is considered “non-invasive,” making it very safe. There are at least 5 mechanisms that LLLT works by:
- The bioenergetics of the laser is thought to accelerate the functioning of connective tissue cells (called fibroblasts) which facilitates healing.
- The additional energy added to the biological tissue also acts as an anti-inflammatory agent by decreasing the chemical mediators for inflammation.
- When the LLLT beam energizes the cells of small arterioles, nitric oxide (a vasodilator) is released, thereby increasing local blood flow. Increasing local blood flow also facilitates healing in chronically inflamed tissue.
- It is also known that energizing local tissue with LLLT causes the pain receptors in the energized area to become desensitized further decreasing pain.
- The biochemical effect that LLLT has is also theorized to be due to energizing the mitochondria of the target tissue. Mitochondria power the majority of biological processes in mammalian tissue (especially human beings).
What Is Low Level Laser Therapy Used For?
LLLT has been found useful in a number of musculo-skeletal conditions as well as conditions treated with acupuncture. The following is a partial listing of conditions LLLT has been used for:
- Rheumatoid Arthritis
- Fibromyalgia: LLLT has been substituted for the injection of trigger points with local anesthesia. It is more comfortable, there is no dose limitation (such as with the medications injected into trigger points), and is very time efficient (not requiring the anti-septic preparations that trigger point injections require).
- Temporo-mandibular Joint Dysfunction
- Carpel Tunnel Syndrome
- Acupuncture: LLLT has been used as an alternative to the use of needles.
- Wound healing
- Skin ulcers
This is only a partial listing where LLLT has been used.
What Are The Side Effects Of Low Level Laser Therapy?
Although LLLT is very safe, there are a few side effects that can occur:
- Burning/blistering: Depending on the energy of the laser being used, prolonged contact with the skin can cause blistering in people sensitive to this type of therapy.
- Skin rash
- Retinal Damage: The more powerful LLLT units laser beam can deflect and cause retinal injury. Most units recommend that the operator and patient wear protective eye gear when using LLLT.
What Are The Contraindications For Low Level Laser Therapy?
There are a number of conditions where LLLT would not be advised. The following is a partial list of these conditions and situations:
- Use in light sensitive skin disorders (ie. Lupus, Porphyria, etc.).
- Previous history of skin sensitivity with application of LLLT.
- Inexperienced operator.
- Incorrect laser or malfunctioning laser.
- Use with skin sensitizing agents (some antibiotics such as Tetracycline, certain acne skin solutions, etc.).
- Use near the eyes or thin areas of the skull (such as the temporal regions of the skull).
LLLT should always be used under the supervision of a licensed medical practitioner.
The Cochrane Database of Systematic Reviews (an organization that does meta-analysis of existing medical literature on a topic and reports as objectively as possible on the known facts about a topic) reviewed LLLT in 2008 for the treatment of low back pain (the most common chronic pain syndrome in the U.S.). Their findings were as follows:
“Based on these small trials, with different populations, LLLT doses and comparison groups, there are insufficient data to either support or refute the effectiveness of LLLT for the treatment of LBP. We were unable to determine optimal dose, application techniques or length of treatment with the available evidence. Larger trials that look specifically at these questions are required.” (Yousefi‐Nooraie R, Schonstein E, Heidari K, Rashidian A, Pennick V, Akbari‐Kamrani M, Irani S, Shakiba B, Mortaz Hejri S, Jonaidi A, Mortaz‐Hedjri S. Low level laser therapy for nonspecific low‐back pain. Cochrane Database of Systematic Reviews 2008, Issue 2. Art. No.: CD005107 ).
It would appear that for low back pain, LLLT is no more effective than other therapies that heat biological tissue. As is so often the case with alternative therapies, existing well done research studies using LLLT are lacking.
The use of LLLT for chronic pain will have to remain in an optional category until more definitive studies on its usefulness are performed. Overall, it is safe and easily administered.
A strong recommendation for the use of LLLT cannot be made at this time.
I hope you have enjoyed this monograph on LLLT. If you any further questions or comments, please contact me by email. I would love to hear from you and will answer you promptly.
Wishing you joy and good health.