Laser therapy, the new kid on the block for non-drug management of pain and a host of other problems, has spawned persistent questions about how it works and whether the benefits justify the financial investment. Now that evidence-based education is becoming available for laser therapy1, facts can begin to replace the hearsay and hype that make many of us uncomfortable. Practitioners want to know how laser stacks up against the old favorites: acupuncture and massage. Measuring all three side by side in clinical trials would provide the best insight, but only sporadic comparisons of this nature are found, mostly in human medical literature. 2-3 What are the differences in how the therapies work? Laser, acupuncture and massage share the common mechanism of neuromodulation. That is, each activates somatic afferent fibers in the periphery. Peripheral nerves then deliver impulses to the spinal cord and brain to help normalize central, autonomic and peripheral nervous system function. All three have the capacity to beneficially affect local tissue as well, promoting blood flow and reducing inflammation. The differences relate to how each accomplishes these changes. The light energy from laser’s photoirradiation leads to photobiomodulation, a process involving a cavalcade of photochemical events that alter cellular physiology, intercellular signaling and mitochondrial oxidative metabolism.4 What makes laser therapy shine for wound healing is reflected in the way that heightened mitochondrial activity speeds skin closure by increasing collagen production and angiogenesis.5 Acupuncture interfaces with tissue differently than laser, though many of the end effects overlap. That is, both treatments modulate cytokine and chemokine levels, encouraging resolution of inflammation6. Both assist in neurologic recovery through neuromodulatory analgesic and neural regeneration pathways 7-8-9-10-11-12. However, the acupuncture of today employs filiform needles that directly engage connective tissue and collagen fibers, altering the cytoarchitecture of fibroblasts and tugging on somatic afferent nerve fibers in the vicinity. Sequelae of needle stimulation include local cytokine changes, neural receptor activation, blood flow changes and action potentials transmitted to the spinal cord and brain. Central nervous system changes reflect generalized neuromodulation and modified neuroendocrine regulation. Moderate-pressure massage makes itself known to the nervous system through pressure-sensitive mechanoreceptors in the skin, subcutaneous tissue and myofascia. Signals from treated tissue travel to the spinal cord and brain, where neuromodulation takes hold, in many ways similar to that from acupuncture and laser therapy. 15 How does the practitioner know the treatment is working? Acupuncture and massage provide immediate feedback through the delivery device; laser does not. That is, a skillful practitioner inserting an acupuncture needle gauges the amount of resistance the needle encounters as it penetrates one or more layers of muscle. This mechanical information conducted through the needle informs the acupuncturist about the state of tone, tension and tenderness in a muscle. Reactions from the patient further advise the acupuncturist about the degree of stimulation taking place within the patient’s nervous system. An experienced massage therapist develops palpatory techniques that convey other types of information. Feeling the tissues respond to touch and the myofascia melt under one’s palms during indirect release techniques provide moment-to-moment messages about how the patient’s body and mind are responding. Laser, like other instrument-driven methods such as ultrasound therapy, limit the amount of tissue engagement by the practitioner unless she or he makes a point of palpating the patient during or soon after treatment. Despite this limitation, all three modalities can fit seamlessly into integrative pain medicine treatment plans. Blending them maximizes the benefits to the patient by multiplying the mechanisms of action at play. How does research support compare between acupuncture, massage and laser? In a recent study from the Netherlands that evaluated non-drug treatment effectiveness for chronic spinal cord injury pain in humans, massage ranked among the most common treatments sought while acupuncture stood among those considered most effective16. That laser therapy did not receive mention may reflect the lag time in adopting laser therapy among some rehabilitation centers. This may change once awareness about laser therapy for spinal cord health spreads. Research-based indications for acupuncture span the gamut from pain control to reproductive disorders, and from gastrointestinal motility regulation to control of itch in atopic patients. For laser and massage, broad support has built around experimental animal and human trials, but few studies exist in the veterinary realm. Likely, the evidence-based indications for laser and massage will increase to rival that of acupuncture when more veterinary colleges begin researching these techniques. Performing studies on massage and laser can be challenging. At least with acupuncture, the correct “dose” of stimulation is fairly standard. Knowing one stimulated a needle “enough” depends either on the sudden increase in needle resistance to twirling—a phenomenon called “de qi”—or to the amount of muscle twitch in low-frequency electrical stimulation. Electroacupuncture studies have identified optimal lengths of treatment and frequency settings, and specifying a precise neuroanatomic target for comparative acupuncture research is possible with acupuncture. For laser and massage, the stimulus diffuses into and influences more of the surrounding tissue region. The proper “dose” of massage and laser therapy remains somewhat nebulous. Questions linger about how to optimize laser power, wavelength, energy density and frequency to make laser treatments consistent and reliably effective across species. Narda Robinson, DVM, DO, Dipl. ABMA, FAAMA, oversees complementary veterinary education at Colorado State. FOOTNOTES 1. Colorado State University. Class IV Laser Therapy Symposium. October 24, 2010. Accessed at http://www.cvmbs.colostate.edu/clinsci/ce/products/28-lasertherapy.aspx on 08-25-10.. 2. Van Middelkoop M, Rubinstein SM, Kuijpers T, et al. A systematic review on the effectiveness of physical and rehabilitation interventions for chronic non-specific low back pain. Eur Spine J. 2010. Jul 18 [Epub ahead of print]. 3. Pfefer MT, Cooper SR, and Uhl NL. Chiropractic management of tendinopathy: a literature synthesis. J Manipulative Physiol Ther. 2009;32(1):41-52. 4. Eels JT, Wong-Riley MTT, VerHoeve J, et al. Mitochondrial signal transduction in accelerated wound and retinal healing by near-infrared light therapy. Mitochondrion. 2004;4:559-567. 5. Zhou H.L., Zhang L.S., Kang Y., et al. “Effects of electro-acupuncture on CNTF expression in spared dorsal root ganglion and the associated spinal lamina II and nucleus dorsalis following adjacent dorsal root ganglionectomies in cats.” Neuropeptides. 2008; 42(1):95-106. 6. Mafra de Lima F, Villaverde AB, Salgado MA, et al. Low intensity laser therapy (LILT) in vivo acts on the neutrophils recruitment and chemokines/cytokines levels in a model of acute pulmonary inflammation induced by aerosol of lipopolysaccharide from Escherichia coli in rat. J Photochem Photobiol B. 2010 July 27. [Epub ahead of print]. 7. Mafra de Lima F, Costa MS, Albertini R, et al. Low level laser therapy (LLLT): attenuation of cholinergic hyperreactivity, beta-2-adrenergic hyporesponsiveness and TNF-alpha mRNA expression in rat bronchi segments in E. coli lipopolysaccharide-induced airway inflammation by a NF-kappa B dependent mechanism. Lasers in Surgery and Medicine. 2009;41(1):68-74. 8. Barbosa RI, Marcolino AM, Roberto de Jesus Guirro R, et al. Comparative effects of wavelengths of low-power laser in regeneration of sciatic nerve in rats following crushing lesion. Lasers Med Sci. 2010;25:423-430. 9. Robinson NG. Laser therapy may work on TL IVDD. Veterinary Practice News. 03/02/10. Accessed at http://www.veterinarypracticenews.com/vet-practice-news-columns/complementary-medicine/laser-therapy-may-work-on-tl-ivdd.aspx on 08-25-10. 10. Konstantinovic LM, Cutovic MR, Milovanovic AN, et al. Low-level laser therapy for acute neck pain with radiculopathy: a double-blind placebo-controlled randomized study. Pain Medicine. 2010;11:1169-1178. 11. Robinson NG. Acupuncture for neurologic recovery. Veterinary Practice News. 07/23/10. Accessed at http://www.veterinarypracticenews.com/vet-practice-news-columns/complementary-medicine/acupuncture-for-neurologic-recovery.aspx on 8/26/10. 12. Robinson NG. Evidence points to acupuncture for disk disease. Veterinary Practice News. Accessed at http://www.veterinarypracticenews.com/vet-practice-news-columns/complementary-medicine/evidence-points-to-acupuncture-for-disk-disease.aspx on 08-26-10. 13. Langevin HM, Churchill DL, Wu J, et al. Evidence of connective tissue involvement in acupuncture. The FASEB Journal. 2002;16:872-874. 14. Napadow V, Ahn A, Longhurst J, et al. The status and future of acupuncture mechanism research. Journal of Alternative and Complementary Medicine. 2008;14(7):861-869. 15. Robinson NG. Neurophysiology of medical massage. Veterinary Practice News. August 2010. [In press.]. 16. Heutink M, Post MW, Wollaars MM, et al. Chronic spinal cord injury pain: pharmacological and nonpharmacological treatments and treatment effectiveness. Disabil Rehabil. 2010 Aug 9 [Epub ahead of print].
