Back Problems in Horses

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356 – October, 2014

By Heather Smith Thomas

There are many types of back injuries in horses, including acute and chronic problems and repetitive injuries due to use of the horse. Any of these can hinder ability to perform. Tia Nelson, a veterinarian/farrier in Helena, Montana, says back problems cover a wide spectrum of situations and present a variety of signs. “The horse may simply not be performing as well as you’d expect, or may suddenly change behavior and start bucking. He may be reluctant to take a certain lead, or reluctant to run if he’s a racehorse, or refuse to jump if he’s a hunter/jumper. He may not want to go downhill. A sore back can be very inhibiting for any athletic horse. Some horses resent being saddled because they know the saddle will cause more pain. They become cold-backed or sour about having a saddle put on, or having a rider get on. Identifying the problem can sometimes be a challenge, however, to pinpoint where it is,” says Nelson.

The horse’s back is very long, with many regions at risk for injury, strain and pain. “I see a lot of lower back pain due to strain, and also a lot of saddle fit issues. Back pain can be due to something as simple as improper saddle fit or as complicated as being kicked or wrenching the back when slipping/falling, or just putting a foot wrong. The back can be injured if a horse pulls back and the rope breaks and he tumbles backward,” says Nelson.

“If a horse’s front feet are too long in the toe, with or without underrun heels, his lower back may show compensatory pain. If one part of our body hurts, we try to protect it by taking the weight off that part. A horse trying to put less weight on the heels of his front feet will be using his lower lumbar spine too much, trying to shift more weight to the rear legs. We see horses that are back sore because they are actually foot sore. As soon as we correct the foot issues, the back pain resolves,” she says.

Kent Allen, DVM, sport horse veterinarian at Middleburg, Virginia (Virginia Equine Imaging), says back problems are more common than most horse owners realize. “Horses with back pain often present as avoidance behavior or a performance problem. The horse is trying to avoid what you want him to do, because it hurts,” says Allen.

“Back pain is often a primary problem. It is not always secondary to hind limb lameness or asymmetry but may be a primary bony problem in the back. This greatly affects performance, and doesn’t necessarily show up as a lameness, and doesn’t necessarily come from a lameness or asymmetry issue in the distal limbs,” he explains.

“This is a change from how we viewed back problems in the past. When I graduated from vet school 37 years ago, treatment for sore backs was to inject the hocks and give the horse bute, and turn it out for a month. But after doing this, I realized these horses were not getting better with this treatment. Very few cases are actually related to gait asymmetry, unless it’s a simple muscle issue—and those horses come around very quickly with treatment. If it doesn’t get better, it’s a different problem,” he says.

“Secondly, bute is not very effective in these situations. Third, turning the horse out and letting it lose fitness and lose more muscle mass is the worst thing you can do. It took us a long time to figure this out and realize that some problems originated in the back itself. One of the first people to figure it out was a veterinarian, Leo Jeffcott, who became a famous professor at Cambridge. He published a series of papers during the late 1970s through the mid-1980s on back problems. Even then, a lot of people didn’t figure it out because the technology necessary to confirm the diagnosis is significant; you either need a big x-ray machine, nuclear scintigraphy, or specialized ultrasound techniques that have only been developed in the last 10 years,” says Allen.

“Understanding and diagnosing back problems is an area in which everything has changed, from what we thought we knew, and what I was taught about it. Much of what young veterinarians today are still being taught is largely wrong. This has been a big challenge for us to get our head around,” he says.

CAUSES OF BACK PROBLEMS IN HORSES

One of the simplest causes is a poorly fitting saddle. “A lot of problems are blamed on poor-fitting saddles that have nothing to do with saddles, however,” says Allen. “The withers is where you can see saddle fit issues, but farther down the back, many problems are attributed to saddle fit but are not,” he explains.

“The second area where we see problems is simple muscle soreness. The horse may have overworked certain muscles and developed muscle spasms. These horses often present with pain and spasm, holding the back rigid. A spasmed muscle atrophies. We can examine the horse and tell it has a back problem, just from the atrophy. The muscle soreness is not related to any bony problems. If you rule out bony problems and the horse has mild back pain that comes and goes, it could be a muscle problem. This can be treated with alternative therapies (electromagnetic pulse, laser, acupuncture, chiropractic, etc.) as effectively as any medical treatments,” he says.

“If your horse keeps having back pain or a performance issue that persists, it’s probably not a muscle soreness because that tends to resolve very quickly with treatment. It may be a more complex soreness because of something else, such as hind legs not moving evenly. This would be similar to when a person hurts a knee and tends to favor it, and a year later the hip hurts because of the way the person is walking. A horse can develop muscle soreness from asymmetrical movement of the hind limbs. This soreness can be easily treated, goes away, and may not come back for a long time—and doesn’t cause avoidance behavior or significant back pain,” says Allen.

Primary bony back problems may be due to various factors. “There is debate as to whether they are developmental problems or wear-and-tear problems, but many may be a mixture of the two. Many problems begin because of malformation or metabolic bone disease issues during the formative years. Then those kissing spines or the OCD lesions in the dorsal articular processes (deeper in the back) just sit there and don’t manifest until several years later when you ask the horse to do some work that bends the back up and down,” he explains. If that horse was out at pasture or doing moderate activity under saddle you might never know he had a potential back problem.

“Some pleasure horses are never asked to bend their back. Horses in that kind of career, even though they have the bony problem, will not manifest it and stay sound. By contrast, a very athletic western horse like a barrel horse, reining horse, cutting horse, etc. that has to really bend the back, stop, turn and pivot, etc. will have a problem show up—but often they don’t manifest it until later in their career. It won’t show up at age 2 or 3, but more likely at age 5 to 8 years old. This is why these problems can be difficult to decipher and have confused a lot of people, because it’s a mix of developmental problems and wear-and-tear. The science is still out on exactly when and where this takes place,” Allen says.

There are three major primary bony problems in the back. “The most common is kissing spines, also called impingement of the dorsal spinous processes—the long skinny bones that protrude up from the top of the vertebrae. They are highest at the withers and continue down the back getting shorter—but still several inches tall. If these protrusions touch each other when the horse bends its back, they can cause pain,” he says.

“The dorsal spinous impingement (kissing spines) occurs when the taller portions of the vertebral protrusions touch each other. If they rub against each other this irritation causes proliferation of new bone. Normal bone has very few nerve endings. When bone proliferates and creates new bone, this is full of pain receptors (nociceptors). This can be a very painful condition,” Allen says.

Arthritis is the second cause of bony back pain. On the sides of each vertebrae (close to where the ribs attach), where the lumbar processes articulate, there are actual joints at the dorsal articular process. One or more of these joints can be arthritic, and not cause a problem until later in life. This osteoarthritis of the dorsal articular process is actually a malformation during the formative years when the horse is young. “Then those joints become arthritic—and become much more arthritic as the horse moves and bends its back. The arthritic bone is also full of nociceptors, and very painful,” says Allen.

Number three is spondylitis. This occurs near the far end of the vertebral column and may have the closest analogy to human back pain (where the lower back meets the sacrum). Fusion may occur between those vertebrae. “There may be big bony spurs across them at the bottom. This happens in humans, dachshunds, horses, etc. In horses it is the least common of the primary bony issues, but it can be dealt with and the horses can continue to perform successfully,” says Allen.

“These bony changes on the bottom of the vertebrae are also proliferative new bone but, interestingly, seems to be the least painful of these three bony conditions. Often the horse owner is not even aware of this condition, and it would take a bone scan or a very powerful x-ray to see it,” he says.

DIAGNOSIS

Dr. Tim Holt, Colorado State University, works with many equine patients that come into the large animal hospital with lameness issues. Holt has found that about 80% of these lame horses have back pain as well. “Often we can take care of the lameness, but the horse still doesn’t want to perform. So we look more closely to try to figure out why they still have pain and don’t want to work. We start looking for back problems such as sore muscles and all the facet joints in the back.” The horse has many small joints along the backbone—several between each vertebrae.

These horses have usually already gone through a lameness workup with nerve blocks and palpation. “I am usually called in when that doesn’t lead to a diagnosis and people still can’t figure out the lameness problem,” says Holt. He tries to pinpoint the problem and then rehabilitate the horses via acupuncture and chiropractic manipulations. These examinations—and assessing the most important acupuncture points—can help identify pathology (showing regions of pain or loss of motion) in specific areas and determine which points may be needed for specific treatments. A thorough evaluation utilizes pressure, palpation and touch of more than 200 diagnostic acupuncture points, observing the horse’s reaction.

“It is important to not make a diagnosis just from one reactive point. You need to put the entire clinical picture together, using the history of the horse, the present complaint and clinical signs, physical findings, lameness exam, and an accumulation of all the reactive diagnostic acupuncture points. We put this all together to help us focus on the area(s) of concern. There may be painful areas due to restricted motion in a certain joint or joints. The back has several sections, with different types of vertebrae in each section. There are 18 vertebral bodies in the thoracic area, for instance. Each one of those has 12 different facet joints. Thus there are about 360 small joints in the horse’s back,” Holt says. It’s no wonder the horse suffers back pain at times.

“In my examination I try to isolate joints in the back that are not moving correctly. If there is even one joint that is not moving, the one in front of it and the one behind it have to work overtime to compensate. Then the muscles around it get sore. My job is to find that spot and try to stimulate that joint to move correctly,” says Holt.

For proper diagnosis of a back problem, it is important to have a clinical examination, and a complete history. Allen says the history is very significant because we need to know if the horse has avoidance behavior or reduced performance. “Does the horse refuse to jump or won’t jump the way it used to? Does it jump differently, or won’t run the way it used to, or runs wide on the turns?” asks Allen.

“There’s a wide variety of performance/avoidance behavior issues and these are sometimes hard to pick up if you don’t listen closely to the horse’s history or are not looking for it. The horse owner should find someone to examine the horse who is experienced in sports medicine in the horse’s particular performance category or someone who can cross-relate from discipline to discipline,” he says.

“Horses with back problems are often girthy; they don’t like being tacked up. They do better once they are warmed up, but you start seeing performance problems you never saw before. Horses with back pain often refuse to do something they’ve done hundreds of times—because they know it’s going to hurt,” Allen says.

“Sometimes it’s really hard to tell whether it’s a mental problem or a physical problem. But the good news is that it’s easier to figure out the physical problem than it is the mental problem.” If you can fix the physical problem and the horse performs well again, then you know it’s not a mental/training problem. A good history of the horse can be a starting point.

The clinical exam is also crucial. “This involves palpating the back. It can be done a variety of ways, but in the end you have to separate the palpation of the dorsal spines (bony structures) from your palpation of the musculature. You are trying to assess each of these separately. Even though we are looking at the back, the pelvis is also very interrelated, so we always palpate the sacroiliac joint, as well.”

It is important to be able to differentiate between muscular pain and bony pain. “Sometimes you can’t, because it runs together; the whole back may be so sore that you can’t separate it out. You also have to palpate the final joint—the lumbosacral joint (the front part of the sacroiliac joint). Then you watch the horse move and evaluate for lameness. We have to realize that lameness may be a separate issue. The horse can have back pain from something like kissing spines or osteoarthritis of the dorsal articular processes and also have navicular disease or sore hocks,” says Allen. The back soreness and the lameness issue may not be related at all.

“When we were trying to figure out ways to accurately diagnose back problems, we wondered what else we could do after checking for lameness, moving the horse, flexing the horse, etc. We began using a weighted surcingle to engage the muscles of the back and possibly induce some pain if that was the problem. This can bring out things you may not see while longeing the horse. Putting weight on the horse can help you sort these things out. There are two ways to do this; you can have someone ride the horse or you can put a weighted surcingle on that horse. We eventually realized we didn’t need the weight of a rider; we were able to see all we needed to see (induce back pain, if there was back pain) with about 60 pounds,” says Allen.

Diagnosis generally takes a combination of techniques—primarily x-ray, and possibly a nuclear bone scan (scintigraphy). “An x-ray with a small portable machine sometimes allows you to see the dorsal spines, but you cannot see the dorsal articular processes. For those you need a big x-ray machine. This would also give you a clear view of the dorsal spinous processes. So if you want to get the back x-rayed take the horse somewhere they do a lot of it and have a big machine,” says Allen.

“Nuclear scintigraphy will show the same things, and will be helpful if you have a multi-limb lameness and a back problem. Those horses need to be checked with nuclear scintigraphy first, to determine what the entire issue is—since it will show all three of the primary back problems quite well—and then have x-rays after the scintigraphy has pointed out an area of concern. Spondylitis will show up on scintigraphy or x-rays, but the scintigraphy has the additional advantage of showing the sacroiliac area, which is an area you cannot x-ray,” he explains.

“Additional diagnostics might include newer digital ultrasounds, if the operators have learned the newer techniques on looking at them. You want someone with additional training to do the ultrasound, because this specialty involves both looking at it diagnostically, and treatment; one of the treatments will be ultrasound-guided injection of cortisone into those joints. Blind injections, trying to get into those dorsal articular processes, doesn’t work very well; it has to be guided by ultrasound,” says Allen.

TREATMENTS

Nelson uses a variety of treatments for backs, including chiropractic manipulations and acupuncture. “There are some sore-backed horses whose owners ask me to do chiropractic or acupuncture on them, that I know are sore from feet issues.” For these Nelson addresses the hoof imbalances before she works on the back and upper body problems.

“I probably use chiropractic methods more often than acupuncture. I do motion palpation along the back and identify spots that are not moving the way they are supposed to move. Then I bring the joints into some tension and give a thrust and adjust the back. It’s amazing how much difference this can make for the horse. Sometimes it takes more than one visit, depending on how much is wrong,” she says.

She uses acupuncture mainly when there is muscle pain rather than a bone/joint problem. “If I am palpating and I feel that it’s a muscle problem, acupuncture seems to help,” says Nelson.

“Sometimes I also use non-steroidal anti-inflammatory drugs on a back injury (to help relieve swelling, inflammation and pain) and sometimes I use steroids. It’s important to identify the problem and figure out if it’s an acute injury or a chronic problem. With some horses it can be difficult to resolve an old, chronic injury,” she says.

After a time, however, it may be possible to make the horse more comfortable. “I discuss this with the client and try to determine what we can actually expect, for that horse. We try to figure out what’s going on, and sometimes discover it’s something we can’t fix.” This can be discussed, looking at the horse’s chances for recovery or pain relief.

“I do a lot of physical therapy, acupuncture and chiropractic work on some of these horses to try to rehabilitate them back into training,” says Holt. It’s impossible to pop and manipulate a horse’s back and get the joints back into place like a chiropractor does with humans—since the horse is so much larger, with thicker, stronger back muscles.

“Instead, I work on each individual muscle, and each individual joint within the vertebral bodies. I am not working on the whole back; I take it at each segment—a little part here and there that needs some help,” he explains.

“You can use non-steroidal anti-inflammatory medications and muscle relaxants like methocarbamol (Robaxin) but those won’t work any better than the alternative therapies and in some cases don’t work as well,” says Allen. “I personally think acupuncture is the best treatment for muscle soreness in the back. The western version is called trigger point injections. Both methods work by depolarizing those points along either side of the back. We can also use shock wave—or any type of energy. An acupuncture needle, injection of a product into the pressure point, or shock wave in that region will depolarize those points and relieve simple muscle soreness, but acupuncture is probably the most simple and easiest to accomplish,” he explains.

“Thirty years ago we’d give the horses bute, some Robaxin, and inject the hocks, and turn them out to pasture for a month. But when you hurt your back, your doctor doesn’t tell you to go lie on the couch for a month, watch TV and eat Twinkies. The doctor gives you medication to try to relieve the inflammation and wants you to keep moving—and go to the physical therapist and do the proper exercises,” says Allen.

It’s the same with horses. There are many tools to help stop the pain, and then it’s important to get the horse active again as soon as possible. He’s more able to become active if you’ve stopped the pain. “You want to be able to get back on the horse and ride him again. If the horse was bucking you off because of pain, he’ll buck you off again unless you’ve stopped the pain.”

The goal in human medicine is to get pain under control so we can keep functioning. “In a huge human study, the researchers looked at people who did exercise and people who had surgery for back pain. The results were the same. If you can stay active and develop the muscles to the point where they can step in and help keep the back strong, this is the goal, and this is very similar between horses and humans. So we have to figure out how to stop the pain,” explains Allen.

“We do that with a combination of things. Using NSAIDs and methocarbamol (to relieve muscle spasms) is not very effective. Over 30-plus years of treating horses with back pain, I’ve given lots of these drugs, to very little effect. When we started looking for better ways, we came up with four tools that can help stop the pain,” he says.

“One is mesotherapy. This involves putting small amounts of medication under the skin, with tiny needles. This technique was used initially in Europe. It’s used in human medicine primarily to treat cellulite rather than for pain relief, but these injections intercept some of the sensory nerves and down-regulate the pain,” he says.

“The second tool is shock wave. In some cases we use it on proximal suspensory ligaments, trying to create a healing environment and stimulate cells where the ligament attaches to the bone. In backs, however, we are trying to do something different. There are thousands more pain receptors per centimeter in new-formed bone (arthritic bone) than in regular bone. So we try to hit those pain receptors with the sound waves of shock wave therapy. This can down-regulate them very quickly and very profoundly. Then after 3 to 4 days the pain reception returns but at a lower-than-normal level and stays at that low level for months,” explains Allen.

“Shock wave produces profound suppression of the pain receptors, almost immediately, and then that effect is replaced by a more normal effect which continues for 3 to 6 months. This can be very helpful because we can get the horse back to exercise,” he says. The shock wave can be repeated later, if needed.

“Another way we can relieve pain is to go into the dorsal articular processes (if they are arthritic), with an ultrasound-guided needle to inject cortisone. We must be very careful and specific because the area we are trying to inject is about 2 or 3 millimeters wide. This entails multiple needle injections on both sides, the number depending on how many joints are affected. This is very effective for pain relief.”

The final technique is to treat the bony inflammatory change. “There is one drug, Tildren, which can treat this. It has been used in other countries, but will be licensed in the U.S. sometime this summer. It is given as an IV drip and circulates in the blood. Anywhere in the body that there is bony inflammation it attaches onto it and starts decreasing the bony inflammatory change. It takes several weeks to work, but then it lasts several months. So this is another powerful tool, and a French study shows there is 70% improvement in the horse’s pain and manifestation of pain in back problems after administration of Tildren,” says Allen.

After using one or more of these tools to reduce pain, the next step is to gradually bring the horse back into work. “We want to build muscle to help keep the back strong. If the horse is sound and free of pain, and we can get the horse back to work, the only thing that limits how fast we bring that horse along is simply his fitness condition—how much condition he might have lost,” he says.

“These horses have lost muscle mass from the atrophy (due to spasms) and we need to get it back. Two ways to get muscle mass back are exercise (getting the horse back to work as soon as realistically possible) and a new technology using functional electric stimulation. This uses a special pad applied by a veterinarian or physiotherapist to stimulate muscle masses to contract. We can actually grow muscle mass back again using this kind of stimulation. The horse also needs exercise, but electric stimulation can bring the muscle mass back much more quickly than exercise alone,” explains Allen.

“The goal in treatment is to stop the pain, get the horse back to its job, and grow the muscles back to where they help take over the job of support that the damaged bone can’t do anymore. Intermittently, in that process, depending upon the horse, you may occasionally have to supplement with more pain relief. With some horses, if you can get them to grow the muscle mass back again, you can get them pain free and they can go on without the need for any other treatments/medications. Other horses will be slower and more painful and every few months you may need to help them again with pain relief.”

If a horse has back pain, figure out the cause before treatment is begun. Without the correct diagnosis you are just shooting in the dark, because treatments vary.