Searching for a laser therapy unit? Determining which company sells the best laser for your practice can feel like looking for the perfect mate. Sleek exteriors and claims of amazing achievements may attract us at first, but which one will last and keep us happy over the long haul? Several options have uniquely desirable features, making us wish we could take parts of each to create the ultimate package of reliability and safety, a product that looks good and feels solid. Whether a laser or a lover, we want it all. While someday we may be able to build one to our specifications, for the moment at least, we need to examine prebuilt models and select the one that fits our needs. Most practitioners want a device that supports the spine, softens the muscles and soothes the skin. Ongoing research is identifying which wavelengths, power settings and frequencies make the most meaningful changes in deep and superficial conditions. Two studies from 2012 illustrate how lasers significantly benefit common problems, each deploying different dosing parameters, wavelengths and delivery mechanisms. Disk Disease in Dogs Laser therapy for spinal cord injury has become a mainstay treatment within the integrative pain medicine community. Photomedicine, like acupuncture, confers important clinical benefits for dogs afflicted with disk disease and their institution into treatment protocols should not be delayed. Both can and should be provided for dogs with disk disease at the time of presentation and continued throughout the immediate and long-term post-operative periods. Laser therapy reduces glial scarring, promotes axonal sprouting and inspires nerve regeneration. It reduces inflammation and modulates reactive oxygen species. Providing a treatment that accelerates resumption of ambulation and other activities of daily living reduces suffering on the part of the patient and the family as well as expensive nursing and adjunctive care. In this way, laser therapy, like acupuncture, can make the difference between clients seeing their dogs as facing a life worth living early in the post-operative period rather than considering euthanasia prematurely, as previously discussed.1 A prospective study from the University of Florida evaluated time needed to recover ambulation in dogs afflicted with T3-L3 myelopathy. It compared outcomes in dogs with and without low-level laser therapy (LLLT) after hemilaminectomy.2 LLLT took place daily for five days. Dogs receiving LLLT required three to five days to regain ambulation, in contrast to those in the control group who took a median of two weeks. LLLT consisted of 25 W/cm2 to the skin produced by a head containing 810 nm, 200 mW laser diodes. Researchers estimated an energy density of 2-8 joules/ cm2. Wound Healing in Horses Laser therapy treats delayed or non-healing wounds well. Phototherapy boosts activity in the mitochondrial respiratory chain. It stimulates the enzyme cytochrome c oxidase, thereby propelling oxidative phosphorylation and augmenting output of adenosine triphosphate (ATP). This elevated level of ATP availability supports healthy cell signaling and the metabolic energy to encourage tissue regrowth. Laser therapy activates fibroblasts and keratinocytes and increases DNA replication, angiogenesis, and analgesia. Problems pertaining to non- or delayed-healing wounds in the equine distal limb have plagued practitioners for eons. Research from Oklahoma State University describes how light therapy provides a ray of hope for horses with slow-healing wounds. Investigators utilized a line generated optical scanner with a dual diode system that emitted a rotating sequence of frequencies from 4 – 28 hertz. The diodes produced a 635 nm beam by means of 17 milliwatts (mW) diodes. After they excised a 2.5 centimeter square, full-thickness section of skin on the dorsal mid-metacarpal region of each thoracic limb, one limb received LLLT; the other served as a control.3 LLLT healed the wounds more quickly; their margins contracted and epithelialized without forming exuberant granulation tissue. Rates of healing between LLLT and control limbs differed significantly after day 17. Considering the safety of LLLT along with its analgesic and anti-inflammatory advantages, there seems to be little reason not to offer LLLT as an adjunct for delayed or non-healing wounds. Other Conditions on the Horizon These two studies point to the progress photomedicine is making in evidence-based practice. Clinically, those already performing laser therapy are treating a gamut of clinical maladies that are widely represented in human medicine and dentistry. These range from musculoskeletal pain4-7 and tendinopathy8 to bone repair9, organ dysfunction10-12 and a variety of pain problems, inflammatory, visceral and neuropathic.13 Human and experimental animal studies outpace clinical veterinary counterparts, but the physiologic mechanisms manifested by each species often overlap and readily translate. The main differences between human and non-human treatments pertain to the issue of fur and feathers. Each creates a buffer zone between light and skin, potentially impeding penetration and reflecting the beam. A research trial in horses showed that simply cleaning the hair and skin over a tendon in the limb upped the amount of light absorbed, though not to a statistically significant extent (p=0.5762).14 On the other hand, clipping the hair over the tendon did increase light penetration significantly; cleaning and clipping offered the most profound improvements. Since most practitioners and clients prefer not to clip, one should try to work between the hair and feathers and/or up the treatment dose to account for beam interference. One should make additional adjustments for darkly pigmented fur or skin and animals with tattoos; high-powered lasers can quickly heat a dark region of skin and cause pain. Conclusion The ideal laser would, in this author's opinion, allow us to customize treatments according to power, frequency, wavelength and applicators in consideration of patient size, species and condition. The applicator head should be comfortable for both practitioner and patient. A smooth glass ball at the treating end of the wand offers trigger point massage but some areas may be too tender to press, asking for a lighter touch. Those that have enough power to warm introduce another modality for chronic pain control but pose the possibility of heating tissue excessively if employed incorrectly. Which one would be right for you? Most of us would not seek a mail-order mate and expect the relationship to fulfill and sustain us. Similarly, selecting a laser without taking a look, listen, or feel opens the door to unhappiness. Take the time to test drive the laser in your practice. Can you communicate easily with its interface? Does the wand feel solid for you and comfortable to your patients? Does it let you know it's turned on (for safety) without making irritating noises and beeps that unsettle you, your clients or patients? What is the estimated turnaround time for service? To read about a practice that has had success with laser therapy, click here. Fiberoptic cables and power cords are the Achilles' heels of therapy units. When they break, which they will, you will need a replacement as soon as possible, next day preferred, as patients and clients will likely be eagerly awaiting their next session. Finally, before you say, “I do” and make a commitment, experience a laser therapy session yourself to find out how it feels on the receiving end. FOOTNOTES 1. Robinson NG. Non-surgical options for IVDD? Keeping hope, and dogs, alive. Veterinary Practice News. May 23, 2011. Accessed at http://www.veterinarypracticenews.com/vet-practice-news-columns/complementary-medicine/non-surgical-options-for-ivdd-keeping-hope-and-dogs-alive.aspx. 2. Draper WE. Schubert TA, Clemmons RM, et al. Low-level laser therapy reduces time to ambulation in dogs after hemilaminectomy: a preliminary study. Journal of Small Animal Practice. 2012;53:465-469. 3. Jann HW, Bartels K, Ritchey JW, et al. Equine wound healing: influence of low level laser therapy on an equine metacarpal wound healing model. Photo Lasers Med. 2012;1:117-122. 4. Azizi A, Sahebjamee M, Lawaf S, et al. Effects of low-level laser in the treatment of myofascial pain dysfunction syndrome. JODDD. 2007;1(2):53-58. 5. Jang H and Lee H. Meta-analysis of pain relief effects by laser irradiation on joint areas. Photomedicine and Laser Surgery. 2012;30(8):405-417. 6. Gur A, Cosut A, Sarac AJ, et al. Efficacy of different therapy regimes of low-power laser in painful osteoarthritis of the knee: a double-blind and randomized-controlled trial. Lasers in Surgery and Medicine. 2003;33:330-338. 7. Larkin KA, Martin JS, Zeanah EH, et al. Limb blood flow after Class 4 laser therapy. Journal of Athletic Training. 2012;47(2):178-183. 8. Tumilty S, McDonough S, Hurley DA, et al. Clinical effectiveness of low-level laser therapy as an adjunct to eccentric exercise for the treatment of Achilles' tendinopathy: a randomized controlled trial. Arch Phys Med Rehabil. 2012;93:733-739. 9. Mota FCD, Belo MAA, Beletti ME, et al. Low-power laser therapy for repairing acute and chronic-phase bone lesions. Research in Veterinary Science. 2012;Epub ahead of print./redirect.aspx?location=http%3a%2f%2fdx.doi.org%2f10.1016%2fj.rvsc.2012.07.009. 10. Kirkby KA, Freeman DE, Morton AJ, et al. The effects of low-level laser therapy in a rat model of intestinal ischemia-reperfusion injury. Lasers in Surgery and Medicine. 2012;44:580-587. 11. Yamato M, Kaneda A, and Kataoka Y. Low-level laser therapy improves crescentic glomerulonephritis in rats. Lasers Med Sci. 2012; DOI 10.1007/s10103-012-1229-6. 12. Oliveira FAM, Moraes ACM, Paiva AP, et al. Low-level laser therapy decreases renal interstitial fibrosis. Photomedicine and Laser Surgery. 2012;30(12):705-713. 13. Lorenzini L, Giuliani A, Giardino L, et al. Laser acupuncture for acute inflammatory, visceral and neuropathic pain relief: an experimental study in the laboratory rat. Research in Veterinary Science. 2010;88:159-165. 14. Ryan T and Smith RKW. An investigation into the depth of penetration of low level laser therapy through the equine tendon in vivo. Irish Veterinary Journal. 2007;60(5):295-299.
