Heather Beach, DVM
Back pain is a common finding in performance horses. There are many clinical exam as well as diagnostic techniques available to localize symptoms of discomfort to the back. Treatment of back pain usually includes a combination of medical treatments as well as physical therapy strategies to strengthen your horse’s spine and increase comfort and performance over the long term.
Symptoms of Back Pain
Back pain in horses can present with a variety of symptoms. Some of the more common symptoms include:
- Poor performance/reduced performance which may progress to behavioral problems (rearing/bucking/stopping or running out at fences). Many horses will feel “disconnected” from front to back, or may have a short strided gait in general.
- Discomfort to grooming or pressure over the back. This should be interpreted with caution because some horses may simply be “thin skinned” and may not be experiencing significant back pain. A sudden change in your horse’s response to grooming may be an indicator of back pain however.
- Resistance to saddling, increased “girthiness” or abnormal gait after being saddled.
- Remember, some horses are very stoic! Many will still perform well yet still show evidence of significant back pain on clinical examination. A careful examination of the back should be part of any lameness/soundness evaluation and can be checked even in the absence of performance problems.
Understanding the anatomy of the horse’s back is the first step to managing equine back pain. There are two distinct muscle groups to consider when treating the horse’s back: the longissimus muscles as well as the multifidus muscles.
The longissimus muscles are the external back muscles that we see when we evaluate a horse’s topline. These muscles often palpate sore, and show spasm and external signs of discomfort. The longissimus muscles run the entire length of the horse’s back and can easily get fatigued and sore if they are asked to support and stabilize the entire spine on their own.
Deeper within the spine however, the multifidus muscle is found. This muscle forms attachments between the individual vertebrae. Each segment of this muscle is short and controls only a few vertebrae and the joints between them. Since every segment of this muscle is shorter than the longissimus muscle system, it does a much more effective job of stabilizing and supporting the spine. If the multifidus muscle is too weak and ineffective at stabilizing the spine, the longissimus muscles will work harder to compensate, leading to pain and spasm in the external muscles of the back.
Our goals when treating back pain are to:
- Rule out and treat primary pathology in the back (kissing spines, arthritis between the joints, ligament damage etc.)
- Treat the pain and spasm of the longissimus muscles
- Provide physiotherapy and exercises to recruit and strengthen the multifidus muscles so that the horse can maintain his back pain-free going forward
Diagnosing Primary Back Problems
Radiographs and ultrasound can be performed on the farm to assess the horse for primary back problems. In some instances, a bone scan might be recommended if the case is complicated or not responding as predicted.
Moderate to severe kissing spine lesions. There are overriding dorsal spinous processes with active bony lysis at the sites of impingement.
Besides kissing spine lesions, other primary back problems include injuries to the ligaments of the back, including the supraspinous ligament and the dorsal sacroiliac ligaments. Horses may also have arthritis of the joints or “facets” of the spine. These conditions are best imaged with ultrasound, but often times are brought to our attention following a bone scan that shows active bony turnover in these regions. Treatment for primary back pain depends on the problem found and may include:
- Injections of anti-inflammatory medications +/- shockwave therapy around the sites of kissing spine lesions
- Bisphosphonates such as Tildren or Os Phos
- Thoracolumbar facet injections in the case of joint arthritis
- Rest, shockwave or regenerative therapies in the case of soft tissue injuries
In most cases of primary back pain, there will still be pain and spasm of the surrounding longissimus muscles that will also benefit from treatment.
Treating Back Pain and Muscle Spasm
When we treat the pain and spasm of the longissimus muscles, we are often erasing the symptoms of another problem. Treatment is typically highly effective, but without addressing the underlying reason for the back pain, the effects will only be temporary. Back pain and muscle spasm can result from:
- Primary back pathology as noted above
- Lameness elsewhere in the horse, especially hindlimb lameness
- Poor saddle fit
- Unbalanced riders
- Bracing secondary to gastric ulcers
- Instability of the spine due to weakness of multifidus muscles
Treatment modalities for pain and spasm of the longissimus muscles include:
- Direct injection of anti-inflammatory medications into the back muscles
- Shockwave Therapy
- FES Therapy (Functional Electrical Stimulation)
- NSAIDs (bute, banamine, previcox)
- Muscle relaxants — Robaxin
- Alternative medicine – chiropractic and acupuncture treatments
Strengthening the Back
Following treatment for back pain, it is crucial that the horse begin working properly and engaging in targeted physiotherapy to strengthen the stabilizing muscles in order to achieve lasting results. If the horse and rider team are experienced, this can be achieved through consistent work under saddle with proper riding technique that encourages the horse to lift through the back and engage the core muscles. In some instances, the use of properly applied training aids on the longe line can be beneficial.
Functional electrical stimulation (FES) therapy is a very effective treatment for strengthening all the muscles of the back. FES therapy can also effectively treat muscle spasm and help restore symmetry to the horses muscles when one side has become over or under developed.
Carrot stretches, or “dynamic mobilization” are another proven physiotherapy approach to strengthening the mutifidus muscles of the horse’s back. In this article by Dr. Hilary Clayton, the correct method for performing carrot stretches is shown with easy to follow photos and explanations of the technique.
For some horses, back pain is a recurring problem that requires maintenance and attention on a regular basis. For other horses, breaking the pain cycle and allowing them to use themselves properly will mean that their ongoing maintenance is minimal.