Author: Bernard E. Filner, MD
Source: Meditech International Inc.
Low-level laser therapy (LLLT) has only been used in the United States since 2002, although it has been used widely in Europe and Asia for the past several decades. I admit to being biased—originally against it, and now energetically in favor of more widespread use of this valuable technology. Insurance companies are very short-sighted in refusing to pay for this therapy; it is less costly, safer, and allows for a more “complete” treatment of chronic pain syndromes.
It is known that infra-red laser beams will penetrate to various depths, depending on wavelength (the 830 nanometer [nm] wavelength will penetrate to a depth of nearly 5 cm). The laser beam at a low power (under 200 milliwatts [mW] or so) will not heat the soft tissue that it reaches, even with continuous use. When the beam hits the cells that line small arterioles, nitric oxide (a vasodilator) is released, thereby increasing local blood flow. Additionally, the laser will “desensitize” local nociceptors, thereby decreasing or eliminating pain at the site. There is also some evidence that the laser beam will decrease inflammation, especially chronic inflammation (although acute inflammation can be aggravated by the increased local blood flow) (1-4).
The world literature is filled with hundreds, if not thousands, of papers detailing studies on the use of low-power lasers to treat various conditions. Many of these papers are confusing, give conflicting results, and often lead to a presumption that the technology is not well understood, and is certainly not very effective or “ready for prime time.” However, careful review of the literature reveals that most of these studies are not comparable, using different types of equipment, different wavelengths, different treatment protocols, different wattages (power), and different endpoints to evaluate efficacy. Hopefully, with increased use of this technology, this will change. I hope to be able to contribute to the growing standardization of this literature (5,6).
I have found LLLT to be most useful for inactivating myofascial trigger points. I have been in practice treating chronic pain for 29 years. During the first 19 years (and for a few patients since) I administered approximately 450,000 trigger point injections. Since I began using LLLT in 2004, I have inactivated approximately 150,000 individual trigger points with this modality (only four could not be inactivated—three due to the depth of large buttocks, and one due to a dense pectoral muscle in a bodybuilder). I have found the use of LLLT to be most gratifying in the treatment of patients with fibromyalgia. These patients are extremely sensitive to any treatment that causes pain. They are often in bed for several days after receiving only a few trigger point injections, and many of these patients have too-numerous-to count numbers of trigger points, literally everywhere. Use of the LLLT has dramatically changed the outlook for treatment of these patients.
I can spend 45 minutes to one hour inactivating all of the patient’s trigger points without fear of drug toxicity, setting off widespread pain, or incurring any risk or pain associated with the treatment. Patients can then participate in stretching, general exercise, and activities of daily living (ADLs), and avoid bed rest after their treatments. I am presently performing a double blind, placebo-controlled study on the use of LLLT for inactivating myofascial trigger points. A review and meta-analysis of trials of the efficacy of LLLT in the management of neck pain was published in The Lancet in 2009 (7).
Most recently, I have developed a technique for treating migraine headaches by aiming the laser at the sphenopalatine ganglion, and I have submitted an abstract outlining the protocol. It is interesting to note that injection of botulinum toxin in the glabellar area, above the nose, is effective in treating migraines. The toxin would have to diffuse about 2-3 cm in order to reach the sphenopalatine ganglion. This ganglion uses acetylcholine as its neurotransmitter, so the toxin would have an effect here by inhibiting its release. Thus it is reasonable to speculate that the balance between the sympathetic and parasympathetic influence on the blood vessels of the pia mater may play a role in the development and onset of migraines.
There is some experience in treating osteoarthritis and rheumatoid arthritis with LLLT. In my experience, much of the pain that patients ascribe to their arthritis (osteo, rheumatoid, gouty, psoriatic, etc.) results from activating trigger points in the involved musculature and is actually secondary to tightening of the attached musculature and bringing the inflamed or destroyed joint surfaces more closely together. Inactivating the involved trigger points alleviates much, if not all of the pain. It also helps to explain the sensitivity of arthritic joints to decreases in barometric pressure and other weather changes, which can be mediated through the effect on the trigger points in the attached musculature.
One of the most common instances of this phenomenon in clinical practice is the false assumption that most back pain in middle-aged patients is secondary to arthritis of the spine, seen with “normal” aging. Invariably, careful examination of the cervical and/or lumbosacral spine reveals active or latent trigger points. Inactivation of these points provides a correct diagnosis and temporary relief of the pain. A program of careful, rigorous stretching of the appropriate muscles, preceded and followed by moist heat, should result in progressive, steady improvement. If not, a vigorous search for perpetuating factors (including postural changes secondary to an excessively pronating gait, marginal deficiencies of hormones and/or vitamins, structural changes due to previous surgery and/or arthritis/fusions, etc.) must be undertaken, and corrections made, in order to continue the improvement. Appropriate medications also need to be in the mix. Pure antiinflammatory agents, while useful for some types of arthritis, will not alleviate myofascial pain. There is no evidence that trigger points are inflammatory in nature; the drugs will work only if they also have analgesic activity (8).
As was mentioned earlier, the depth of penetration of an infra-red laser beam is determined by its wavelength. Extensive studies have demonstrated the deepest penetration to be achieved by 820-840 nm. The FDA has classified these lasers as follows: I, II, IIIa, IIIb, and IV. Basically, class I and II include laser pointers, scanners, etc. These are very low power and do not penetrate the skin very deeply. Class IIIa are basically light-emitting diodes (LEDs), and are functionally heat lamps. They are not, in my experience, effective in treating myofascial pain or other deep pain conditions, and they may cause mild skin burns or irritation. Class IIIb are true lasers, less than 600 mW of power, and do not heat the skin or underlying tissue; depth of penetration is determined by wavelength. Class IV lasers are not truly “low” power. They are usually in the two to 10 watt range, and are the ones usually found in operating rooms and dermatology/plastic surgery clinics. They can heat tissue (in fact can vaporize tissue with continuous use), are a fire hazard, a burn hazard, can reflect off metal surfaces to cause burns and/or fires, and cost from two to five times the cost of the other classes of lasers. They can be quite dangerous, and in a pain clinic must only be used in ultra-short pulses (in order to avoid burns and fires). Therefore, very careful evaluation of the equipment and vendors’ claims is called for when purchasing a system. There are numerous resources on the internet and basic webinars on laser therapy of various conditions. The vendor should bring in their equipment for a demonstration before you purchase it.
- Tuner J, Hode L. Low level laser therapy—clinical practice and scientific background. In: Turner J, Hode L, eds. –Low Level Laser Therapy—Clinical Practice and Scientific Background. Spjutvagen, Sweden: Prima Books;1999:101-104.
- Sattayut S, Hughes F, Bradley P. 820 nm gallium aluminium arsenide laser modulation of prostaglandin E2 production in interleukin-1 stimulated myoblasts. Laser Ther. 1999;11:88-95.
- Bjordal JM, Johnson MI, Iversen V, et al. Photoradiation in acute pain: a systematic review of possible mechanisms of action and clinical effects in randomized, placebo-controlled trials. Photomed Laser Surg. 2006;24:158-168.
- Chow RT, David MA, Armati PJ. 830 nm laser irradiation induces varicosity formation, reduces mitochondrial membrane potential and blocks fast axonal flow in small and medium diameter rat dorsal root ganglion neurons: implications for the analgesic effects of 830 nm laser. J Peripher Nerv Syst. 2007:12:28-39.
- World Association of Laser Therapy. Consensus agreement on the design and conduct of clinical studies with low-level laser therapy and light therapy for musculoskeletal pain and disorders. Photomed Laser Surg. 2006:24:761-762.
- Dundar U, Evcik D, Samli F, Pusak H, Kavuncu V. The effect of gallium arsenide aluminum laser therapy in the management of cervical myofascial pain syndrome: a double-blind, placebo-controlled study. Clin Rheumatol. 2007;26:930-934.
- Chow RT, Johnson MI, Lopes-Martins RAB, Bjordal JM. Efficacy of low-level laser therapy in the management of neck pain: a systematic review and meta-analysis of randomised placebo or active-treatment controlled trials. Lancet. 2009;374:1897-1908.
- Travell JG, Simons DG. Myofascial Pain and Dysfunction. The Trigger Point Manual. Volumes 1 and 2. Media, PA:Williams &Wilkins; 1983 and 1992.
BERNARD E. FILNER, MD, graduated from Oberlin College (BA, cum laude with high honors in biology) and the Albert Einstein College of Medicine (Alpha Omega Alpha). He practiced anesthesiology for 17 years, after a residency at the University of California at San Diego. For the past 28 years, he has had a solo practice of pain medicine in Rockville, Maryland. If you have any questions or concerns about the information contained in this article, contact Dr. Filner via email at email@example.com.
From The Pain Practitioner, Fall 2014 issue. Join the Academy to receive The Pain Practitioner.