Written by Kristine Hamman
Investing in modalities for clinical practice can be daunting, especially when we’re faced with a varied case load and a budget that limits the number of tools we can buy. In a recent lecture by Laurie McCauley, she shared which modality she would choose, and why.
Laser is a highly versatile modality, effective on a broad spectrum of conditions, with ample research to guide effective treatment protocols and approaches. Its results are quick and cumulative.
With evidence to back it up, we see why Laurie reaches for her laser first.
Laser is extremely versatile.
It’s effects include:
- reducing inflammation and edema (both pitting edema in the interstitial fluid, and edema in tissues and in joints)
- improved lymphatic drainage
- reducing pain
- accelerating wound and joint healing
- reducing osteoarthritis pain and inflammation
- promoting muscle regeneration
- enhancing endurance
- reducing post-injury myopathy due to tissue trauma
- inhibiting bronchoconstriction/spasms
- enhancing stem cells
- reducing neuropathic pain, as we see with back pain and
- enhancing recovery in traumatic brain and spinal cord injuries or post stroke, where laser actually goes through the skull and into the brain or spinal cord.
To say this is impressive would be an understatement, but it does seem too good to be true.
Research Backs Up Laser’s Effects
Below are some amazing studies on laser’s effects on the healing of various tissues.
Laser in Skin Healing
- Al Wabtan did a series of studies where they compared the effects of laser on burns and on diabetic wound healing, and found that the burns needed a high number of J/cm2 for effective treatment, whereas wounds needed about half the amount. Most studies done on skin healing are done around the 600 nm range or 800-830 nm (Al-Wabtan & Zhang, 2004).
- Laser reduces infection in wounds (Mathur et al., 2016).
- Laser increases healing of wounds (Ranjbar & Takhtfooladi, 2016).
Laser in Bone Healing
- A single laser session before TPLO surgery resulted in significant improvement in weight bearing two weeks post-operatively when measured on a force plate (Rogatko et al., 2017). An improved weight distribution earlier in recovery may lead to reduced movement compensation and have a protective effect on the contralateral cruciate.
- Bone healing was significantly improved in rats receiving laser therapy when compared to a control group, with a slight improvement over the control at day seven, and a significant improvement over the control group on days 13 and 25 (Favaro-Pipi et al., 2011).
- Rats with bilaterally severed thighs were divided into groups. In one group, only one thigh was treated with laser, while the other group received no laser. In the treated group, wound healing was improved in both thighs when compared to the control group, indicating an improved wound healing even when laser was applied some distance from the wound (Rochkind et al., 1989).
When you consider these results, you may think, ‘Why am I not lasering after every surgery or procedure?’ Laser is not only bio-accumulative, meaning the more we treat the more effective it is, but it also has a systemic effect, as the study on rats with cut thighs demonstrated; even though the untreated thigh was not within the treatment radius of the lasered thigh, the untreated side still improved (Rochkind et al., 1989).
A new type of therapy which is making use of this systemic effect is called photohemotherapy– hem meaning blood, where we can use laser’s property of causing photons to bind to the hem and then become transported throughout the body.
- Photohemotherapy was applied to children whose asthma was so bad they were hospitalised. The results of blue and red light photohemotherapy together with standard asthma therapy were compared with the results in patients who received only standard therapy. Blue light therapy was quickly identified as being more effective than red light therapy, and many children were switched over to this treatment. They showed rapid improvements of clinical symptoms in 7-14 days. At a follow-up three years post-treatment, they found a 1.3-fold improvement in control of the children’s asthma and almost a 1/3 less hospital visits than among the children who received only the standard therapy (Ostrovskiy et al., 2014).
The above studies therefore show is a bioaccumulative, local and systemic effect that is also long-acting.
How Many Sessions Until We See Results?
Laurie’s rule of thumb when discussing this question with owners: If there is no change within four treatments, we need to change the modality (even though we expect results after the first session, and may make a change sooner if needed). If we are treating an injury or something pain related (acute) we can usually see results within four to six sessions (although results are usually seen in two to three); if we’re treating a chronic condition, such as iliopsoas strain, we can expect to need six to ten sessions (although we expect results at between four and six sessions). This is the classic example of under-promise and over-deliver. With an injury like an iliopsoas strain it's also important to continue with weekly treatments (once the acute pain has been managed) until the dog is back to full activity, especially in sporting or competitive animals.
Is There More to Laser in Sports Medicine?
In sports medicine we want to apply laser in lower doses. Why? Well, most of the reasons are hypothesised from what we already know; we know that high doses reduce pain, so using high doses could mask pain and make an animal more susceptible to tissue damage (Albuquerque-Pontes, et al., 2015). We also know high doses cause the tissues to fatigue as high doses decrease ATP production, which reduces the messages to our brain (which is what we want with pain management); then the muscle will not get the energy it needs to fully contract and stretch. Low doses of energy increase ATP production so that the cells can do whatever they need to faster, better or longer.
With that in mind we can use it as a pre-conditioning tool to enhance stamina, performance and recovery, because of its effects. Obviously one can’t treat the whole animal pre-competition, so Laurie advises treating the acceleration muscles of the hindlimb (gastrocs, hamstrings and glutes) and the deceleration muscles in the front limbs (triceps and biceps) along with areas of previous injury as a starting point.
OK … So Why Do I Need to Know My Laser and My Variables?
Although the research studies mentioned show us part of the truth, if you remember anything after reading this it should be, ‘Know your laser and know your variables.’ You might wonder what the big deal is – your laser has preset protocols which work for the most part, so why should you bother changing the variables? Surely if your laser works, it works, right?
Laurie uses a really good analogy comparing a laser to a camera. If you have an average camera you’ll be able to take a picture with the presets and although the picture may be blurry, you’ll make out that it’s a dog; but if we take a picture with a really good camera, where you can choose your own settings and learn the best combinations of these settings, you’ll end up with a much clearer and more defined image. The same is true with laser. They don’t all have the same delivery mechanism and their variables differ, so it’s important that you get to know your laser so that you can derive optimum benefits.
Two studies where laser seemingly had no effect highlight the importance of knowing your variables and applying them correctly. The first study looked at pain management after back surgery where the laser was applied at a 45 degree angle; the report does not specify whether or not there was contact with the skin. If we consider the basic laws of physics, we know that without contact there would be a great deal of reflection occurring at that angle, which would significantly reduce the penetration and absorption of energy in the tissue (Bruno et al., 2020). This study, along with the other mentioned, both used far too little energy per point than would have been needed to reach the tissues they were targeting (Bruno et al., 2020; Kennedy et al., 2018). Although laser is not effective in all scenarios, this just highlights just how important variables such as different wavelengths are. For example, when working on anything in the 600 nm range with low energy, we will have reduced penetration and will more effectively treat superficial or topical structures.
The more we know and understand our variables, the safer and better our effects will be. We see this with the treatment of cancer, which has always been a contra-indication for laser. There is promising research where blue or near infrared lasers have been shown to work with nanoparticles within a tumor, destroying the cancer from the inside by reducing the cell viability by up to 90% (Kelkar et al., 2016). As Laurie puts it, ‘If you know the rules, you can use them effectively.’
Laser has such a versatile treatment scope, but to use it effectively we need to spend time getting to know our modality, learning the most effective variables and, most importantly, using our device. Only by using this device as part of our daily treatments will we learn how to apply our variables, truly appreciate its full capability and achieve optimum results in our patients.
- Optimum Laser Therapy, Laurie McCauley: https://www.optimumpetvitality.com/optimum-laser-therapy
- Laser Therapy: Bringing the Physiology to the Clinical, Narda Robinson
- The Science & Safety of Lasers & LEDs, sans Sales Pitch, Narda Robinson
- Albuquerque-Pontes, G., de Paula Vieira, R., Tomazoni, S., et al. & Leal-Junior. 2015. Effect of pre-irradiation with different doses, wavelengths, and application intervals of low-level laser therapy on cytochrome c oxidase activity in intact skeletal muscle of rats. Lasers Med Sci. 30 (1): 59-66. doi: 10.1007/s10103-014-1616-2. Epub 2014 Jun 24.
- Al-Wabtan, F.A & Zhang, X.Y. 2004. The comparison of effects between pulsed and CW lasers on wound healing. J Clin Laser Med Surg. 22 (1): 15-18
- Bruno, E., Canal, S. & Antonucci, M., et al. 2020. Perilesional photobiomodulation therapy and physical rehabilitation in post-operative recovery of dogs surgically treated for thoracolumbar disk extrusion. BMC Vet Res 16: 120. https://doi.org/10.1186/s12917-020-02333-3
- Favaro-Pipi, E., et al. 2011 Photomedicine and Laser Surgery, 23 (5).
- Kelkar, S., McCabe-Lankford, E. & Albright, R., et al. 2016. Dual wavelength stimulation of polymeric nanoparticles for photothermal therapy. Lasers in Surgery and Medicine, 48: 893–902
- Kennedy, K., Martinez, S. & Martinez, S., et al. 2018. Effects of low-level laser therapy on bone healing and signs of pain in dogs following tibial plateau leveling osteotomy. American Journal of Veterinary Research, 79 (8) : 893-904. https://doi.org/10.2460/ajvr.79.8.893
- Mathur, R. K., Sahu, K., Saraf, S., Patheja, P., Khan, F. & Gupta, P. K. 2016. [Epub ahead of print]. Low-level laser therapy as an adjunct to conventional therapy in the treatment of diabetic foot ulcers. Lasers Med Sci. Nov 29. [Accessed December 27, 2016].
- Ostrovskiy, E. I., Karandashov, V. I. & Shatokhina, S. N., et al. 2014. Effects of photohemotherapy on the clinical course of bronchial asthma. Almanac of Clinical Medicine https://doi.org/10.18786/2072-0505-2014-35-60-65.
- Ranjbar, R. & Takhtfooladi, M. A. 2016. The effects of photobiomodulation therapy on Staphylococcis aureus infected surgical wounds in diabetic rats. A microbiological, histopathological, and biomechanical study. Acta Cir Bras, 31, 498-504
- Rochkind, S., et al. 1989. Systemic effects of low-powered laser irradiation o peripheral and central nervous system, cutaneous wounds, and burns. Laser Surg Med. 9: 174-182
- Rogatko, C. P., Baltzer, W. I., Tennant, R. 2017. Preoperative low level laser therapy in dogs undergoing tibial plateau levelling osteotomy: A blinded, prospective, randomized clinical trial. Vet Comp Orthop Traumatol 1/2017 www.vcot-online.com on 2017-04-02 | ID: 1000503128 | IP: 220.127.116.11
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