Watching The Horse Move
How does the horse with back pain move? Very carefully!
Although obvious lameness may be nonexistent, the movement behind is generally stiff and with limited stride. The horse will resist or refuse to engage the hindquarters well. In early cases, particularly those involving instability at a vertebral joint, symptoms may come and go completely or always be low-level but subject to sudden worsening. The signs may occur when the horse is working and may mimic tying-up. In fact, many horses with severe back pain are misdiagnosed as having tied up. The major difference symptomatically is that the pain becomes more obvious after the horse has stopped working, not during work, and typically gets worse the longer the horse stands still.
As time goes on, movement behind may become more restricted, usually with some degree of muscle loss, and the horse may actually begin dragging or scuffing his toes, sometimes confused with a neurological problem, such as EPM, or a stifle disorder.
Lateral movement and bending is also often obviously affected. The horse will stiffen and brace himself against the leg you are attempting to get him to bend around, in effect pushing back against you. He may comply with your cues by a correct movement of the forehand but the hind is "locked."
At the walk, the normal relaxed swing through the back is lost and the feel is like perching on a fence post.
The trot may be his best gait but without the ability to engage behind for either extended or faster rates.
The canter is often rough and heavy on the forehand. The horse may refuse one lead entirely and be prone to cross-cantering.
Jumping is especially problematic because to do this correctly the horse needs to bend at the thoracolumbar junction. A good bascule also requires good bending through the spine. Some horses may even begin to refuse to jump due to pain.
With back pain, the horse will tend to drag the hind end along rather than flexing his legs well. If the problem is impingement of the dorsal spinous processes, the horse may be less free with using his neck for balance as raising the head causes the back to hollow, bringing these bones into closer apposition.
On turnout, horses with back pain want to buck and kick instinctively-a movement that can release the spine-but can't or won't because of the pain. They may begin to buck and kick, but the movement will be feeble and with a short range of motion, often more like a hop than the impressive, "letting loose" kick you will see from a normal horse.
Getting up and down, or rolling, may cause pain, making the horse slow and cautious, avoiding it entirely. Even simple, everyday movements for a normal horse may be painful, such as putting his head up to eat out of a hay rack, putting the head down to graze or bite at a fly.
Diagnosis And Treatment
Although progress has been slow, we are getting better methods available for diagnosing back problems. Standing X-rays can detect "kissing spines." Bone scans coupled with a careful examination that lets the radiologist know where to focus attention to look for both soft tissue and bone activity are useful in linking exam findings with hard evidence of the at least the location of the problem. Ultrasound is also proving helpful. Even thermography can help pinpoint problem areas.
In addition to using ultrasound to locate abnormalities, it is being studied as an aid to diagnosis with local anesthesia. As for lameness of the lower legs, improvement following local anesthesia is the gold standard for diagnostics. Interestingly, a Swedish study published in the Equine Veterinary Journal (January 2006) found that injecting the backs of even clinically normal horses with local infusion of anesthetic around the dorsal spines ("kissing spine"area) improved their freedom of motion. Unfortunately, those horses weren't imaged by bone scan, thermography or ultrasound to see if this corresponded to unsuspected back problems.
Surgery And Meds
Surgery is an option for cases of impingement, but not for other types of problems. Even it were, odds are that surgery should be the last treatment attempted as scarring often ends up causing just as many problems.
Medication options are essentially the same as for arthritis, including aspirin, NSAIDs (like phenylbutazone or flunixin/Banamine) and herbal alternatives. We recommend reserving these options for times when symptoms are particularly severe. Muscle relaxants, like Robaxin, are also sometimes helpful in managing symptoms, especially during flare-ups when muscle spasm is a prominent feature. However, as with human back pain, response to these drugs is often far less than complete.
Fortunately, many other therapies can make the back-sore horse more comfortable. Most are lumped by veterinarians under the heading of "alternative therapy" for horses, but they're pretty standard fare with human physical therapists (see sidebar). Finding the combination that works best for your horse will largely be a matter of trial and error.
Bottom Line
Back pain shouldn't always be dismissed as a secondary problem that will go away when something else is corrected. But because lameness elsewhere can cause back pain due tocompensation, a thorough lameness exam looking for other problems is always in order.
Physical-therapy options-from heat to therapy devices and acupuncture-can provide the horse with significant pain relief. We recommend you discuss these therapies with your vet as the first approach with medication only when necessary.
