This is the second in a series of articles on equine chiropractic evaluation and therapy.
The prevalence of back problems in horses varies depending on the type of veterinary practice involved and the type of horses and disciplines involved. A study done in 1999 found 13% of horses in a mixed equine practice, including show jumpers, dressage and eventing, had related back problems.
Clinicians often have difficulties in assessing obscure lamenesses or performance problems with no specific injuries or localized pain. Leg lameness can cause spinal problems, and back pain can alter gaits to make a horse lame or appear to be lame. Treating the secondary cause will not give long term relief unless the primary cause is also identified and treated. If a horse has back pain impacted by sore hocks, or poor saddle fit, or unbalanced shoeing–those primary issues need to be addressed.
I am not a chiropractor, so I label what I perform as “adjustments” and not “chiropractic”. I also prefer to call these therapies “complementary” instead of “alternative”, precisely because they complement traditional medicine. There are few studies published on how equine chiropractic may work, but theories typically describe vertebral segment (two adjacent vertebrae) dysfunction. This dysfunction involves loss of range of motion (symmetrically or asymmetrically), uneven nerve sensation (pain or numbness), abnormal muscle tension next to the vertebrae (tight or too lax), and signs of inflammation (swelling, heat, pain, redness), or fibrosis (scar tissue).
The goal of therapy then is to reduce all abnormalities and restore as much normal function as possible. The mechanisms that produce this relief may involve release of neuropeptides (endorphins), affecting nociceptive reflexes (pain perception by nerves), or reducing muscle spasms. In response to an injury or to chronic pain, the spine learns new postures or patterns of movement in an attempt to reduce the pain. This adaptation can persist long after the initial injury has healed, and can continue to limit function.
Adjustments can affect mechanoreceptors to inhibit pain and induce reflex muscle relation. The body can then re-educate the spine to assume more flexible, balanced, and relaxed positions and movement. Adjustments may produce a popping noise (an “audible”), but on animals as large as a horse, this is not a consistent event. What often does occur is an almost immediate improvement in range of motion and a visible relaxation of the horse.
This review will continue with a discussion of how I evaluate horses to specifically see if they would benefit from chiropractic treatment, based on direct motion palpation.