Most of us know the use of lasers is growing in mainstream medicine, although we usually think “surgery.” The lasers we field tested for this article don’t use the high power required to cut through tissue. Instead, these therapeutic lasers use low energy levels to speed healing. They have documented effects, and we found obvious improvement in a number of problems during our field tests.
What Lasers Do
At the cellular level, lasers stimulate energy production and cell division. They can also stimulate activity in the cells of the immune/inflammatory system. Lasers can even stimulate acupuncture points.
On a whole-body level, lasers help heal wounds, severed nerves and damaged tendons. Laser therapy can also reduce edema, such as stocking up, by improving circulation in both blood vessels and the lymphatics; control pain; and in some studies, improve healing of cartilage lesions. Response in arthritis cases may hinge on positioning the joint so that the beam can be directed at cartilage surfaces, which is often difficult-to-impossible to reach in horses.
Lasering wounds is one of the most well-documented beneficial effects. Old wounds that would not heal can be stimulated to close, and experimentally created wounds in laboratory animals heal and shrink in size as much as 40% more rapidly than nontreated wounds.
We’ve seen reliable reports that severed tendons have 26% more collagen at 15 days than untreated controls. Arthritis showed positive response in terms of pain and decreased inflammation plus repair of cartilage lesions with hyaline (joint-type) cartilage rather than fibrous cartilage. Painful local trigger points and areas of diffuse muscular pain have responded to laser treatments, as has back pain in horses.
All our test units were equipped with a method to verify laser light was being delivered and warning systems for low battery power. Setting of dosage and frequency was easy. Laser systems are light, small, portable and have no trailing wires or cords. You simply put on your safety glasses, set, point and shoot.
While using them is easy, choosing the correct settings and dosages is not. Lasers vary widely in their wavelength, range-of-frequency settings and power densities. Choosing the correct one and, from there, the correct dosage, can be confusing.
Dosage recommendations from manufacturers vary widely. The scientific literature isn’t much help either. Guidance regarding what Nogier frequency (see sidebar on laser parameters) to use is definitely lacking, particularly if you want published results. On page 8, we list sample treatment protocols from various manufacturers, and those we found to be effective.
Field Trials And Treatment Tips
Our most dramatic results were obtained when treating wounds and tendon/ligament injuries.
However, we found infrared lasers used on fresh wounds can increase the level of swelling or activate bleeding if dosage is too high. There are also reports that show healing may be slowed by intensive lasering of fresh wounds. Red-light lasers did not have this effect but produced the most obvious effects when wounds were several days to a week old (rapid acceleration of healing). Deep, open and non-healing wounds are excellent candidates for the laser. Infrared lasers accelerate healing of small blood and lymphatic vessels, while red light is best for stimulating fibrous tissues and skin cells.
Tendons and ligaments, including curbs, treated with the laser showed rapid pain decrease (often within 24 hours), decreased swelling and rapid healing. One horse with curbs that had been plaguing her for over a year — despite rest, turn out, shoeing changes and a variety of topical treatments — had a marked decrease in pain and swelling with laser therapy. She healed in six weeks. We do recommend the progress of healing be verified by ultrasound, since rapid improvement in pain and swelling may be deceptive.
Soft-tissue problems of joints, such as stifle ligament pain/strain, bursitis (hock, hip), joint capsule strains and injuries (e.g. osselets), also responded well, particularly in terms of pain relief. Effectiveness may be limited to your ability to control active inflammation in the area and that activated by the laser.
For example, when treating osselets, we found it important to start out slowly with low dosages and low frequencies, interrupting treatment for a day or two if too much swelling resulted from the treatment in early stages. Despite this, laser treatments provided significant pain relief, allowing the horses to continue in work while the osselets “set up.” One horse in particular developed classical osselets with dramatic swelling but resolved completely within five weeks, with no residual ankle thickening or loss of motion.
Areas of muscle pain with well-localized, painful “trigger points” — spots where pressure causes an exaggerated reaction — responded well to treatment of the local points. They also responded to lasering the surrounding area using either multiple point treatments in a grid pattern or a cluster head (laser device with multiple diodes/point sources of light designed to treat large areas). When treating muscles where the entire area is tight/hard and sore, or as support for joint problems that often involve muscles soreness as well, either point treatments in a grid or cluster heads are helpful.
It’s especially important to treat the entire length of the muscle — from where it originates on bone to where it inserts on bone (if accessible) — to get the best effects. These tendinous attachments of bone are often just as sensitive, if not more painful, as the fleshy middle portions of a muscle.
Laser stimulation can also be substituted for acupuncture needles of injection into acupuncture points in the treatment of back pain or in any acupuncture prescription. We specifically tried this in connection with acupuncture points on the feet, back and for treatment of symptoms of hormonal imbalance in a mare. Feet were the most difficult to treat, response ranging from no obvious improvement at all to a reduction in lameness equivalent to what you would see with a low dose of phenylbutazone.
Precise point stimulation with low dosages (1 Joule/cm2 or less) directly over the points on the coronary band was more effective than cluster head treatments. Red-light and low-power density infrared units were better than high-power density infrared. This may be because the points are superficial or may have been related to deep penetration causing discomfort from too much inflammation and/or increased circulation deeper in the hoof.
With the backs and reactive flank points in one mare, treatment of specific acupuncture points and trigger points did have obvious benefit. In several instances, acupuncture points that were stiff and unyielding became more supple. This change in tissue texture is similar to the effect achieved after needle placement in reactive points.
Results overall were good to very good, but the laser treatment was not as effective as traditional needling or injection of points (e.g. with Serapin). Laser results were also not as long-lasting (two to three days average) as with more traditional approaches (up to weeks). However, laser acupuncture is safer for the person performing the treatment (some of those points are really tender!), less traumatic to the horse and can easily be done by the owner/trainer after proper instruction.
The most variable response was obtained with joints. It may be impossible to aim the laser beam directly onto cartilage surfaces either because they are inaccessible (e.g. lower joint of the hock has limited movement) or located too far from the skin surface. Best results in terms of pain relief and increased freedom of movement were obtained using infrared lasers with a high-power density, applied in a grid pattern to the surface of the joint. Cluster heads were not as effective.
Treatmen t was often limited by the degree of swelling and heat incited by the laser treatment. Even joints that seemed quiet and cool on the exterior might react this way. When inflammatory reactions could be controlled, analgesia and improved movement was fair to good.
The Respond XL unit’s wavelength is the most versatile we tested. It penetrates well, while the wide variety of frequency options helps in controlling undesired effects that may occur with this wavelength. The addition of the High Powered Laser Probe (HPLP) to the probe options slashes treatment times. The ability to charge batteries when convenient was a big plus. User guides provided with the unit and degree of technical support available from the company are excellent.
Although the LTU-904H’s single wavelength and limited frequency options did not allow for as much fine tuning as the other systems, this laser performed well on a wide variety of problems. The low-power density/longer treatment times needed for most applications (except acupuncture/nerve points) may be a drawback for professionals or busy performance barns treating a number of horses.
However, the low-power density was a plus when it came to avoiding negative reactions, and there seemed to be excellent penetration in tough areas like tendons. This was probably because of the tight aperture on this unit and use of a shield around the aperture to deflect energy bouncing off the skin surface back to the target area.
We found the Thor DD the most complicated, with a wide variety of probes and cluster heads to choose from and a variety of power densities with the red or infrared wavelengths. No other laser we tested offers more ways to get the job done quickly or to tailor treatment parameters to a specific problem. However, high-powered probes risk negative reactions if used improperly.
No barn needs a laser therapy unit to be considered “well-equipped.” Lasers have powerful effects and often a narrow range of effective dosage that will vary depending on the condition being treated and the individual animal’s response.
Lasers should only be used when a diagnosis has been established by a veterinarian and a competent veterinarian or therapist prescribes the laser parameters to be used. However, anyone can learn to operate a laser properly and, used appropriately, they have a lot to offer for improving healing or in the ongoing management of chronic problems where “cure” might not be realistic.
Our first choice is the Respond XL. It was the most versatile, penetrates well, and the HPLP probe addition slashes treatment times, making this unit a good choice for both individuals and professionals. We also appreciated the ability to charge batteries when convenient and excellent user guides, all of which put the operation of this laser well within the capability of owners/trainers.
The LTU-904H is the mighty mouse of this group and is a good, nicely priced choice, if your horse has a chronic problem that is amenable to control with infrared lasers.
The Thor DD unit is the ultimate for professional therapists and veterinarians, but its use is best left in their hands unless you have been thoroughly educated and are following a prescribed treatment program.
Prices And Contact Information: Respond 2400 XL (800/722-1228) Prices: 2400XLUW $4,099; 2400XLSF $3,200; 2400 SLHJ $5,499; 2400XLDX $6,675. Thor (540/337-2264): Lease: $400-$500 per month, depending on probes involved. Purchase Drive units: DDII $3,022; DD $1,959. Purchase Cluster probes 19 diode $1,275; 69 diode $2,025; 104 diode $2,925. Purchase Infra-Red point probes 40 mW 810 nm $1,350; 100 mW 850 nm $1,530; 200 mW 810 nm $2,230. Purchase Visible Red probes 30 mW 680 nm $1,350; 200 mW 680 nm $4,100. LTU (540/337-2264) Purchase $2,100. Lease $200/month.
Also With This Article
Click here to view “What Is Laser Therapy'”
Click here to view “Laser Parameters.”
Click here to view “Frequency.”
Click here to view “Sample Treatment Protocols.”
Click here to view “Lasers And Safety.”
Click here to view “Problems We Treated.”