Enigma: Kissing Spines In Horses – Part 2 – Clinical Signs & Diagnosis

This article is sponsored by Platinum Performance.  It was originally published here: https://www.platinumperformance.com/articles/kissing-spines.html

Clinical Signs

As diagnostic capabilities and the pathological understanding of Kissing Spines have improved, common clinical signs of the condition have also been identified. At the same time, each horse’s pain tolerance and personality differ greatly, resulting in a widespread collection of symptoms that requires imaging to definitively diagnose. “One of the challenges in these cases is helping owners and trainers recognize that the horse may be really struggling and uncomfortable, even if they are not showing any lameness. Frequently, horses with back pain start showing subtle signs early on, and it is always my hope that we can learn to recognize these cases before the horse compensates and has a secondary injury,” says Dr. Melinda Story of Colorado State University’s College of Veterinary Medicine, a well-known performance horse veterinarian boarded in both surgery and sports medicine and rehabilitation, and also certified in both equine chiropractic care and acupuncture. The most common clinical sign that there may be trouble lurking in the back is behavioral changes. These shifts in behavior can range from subtle to dramatic and can present as horses becoming irritable or frantic when confronted with a situation that bends or stretches their back. For instance, barrel racing horses may become agitated in the alley, anticipating the pain they’ll feel when bending around a barrel. While headed to the first barrel, these horses are known to sometimes straighten and run past the barrel in an effort to avoid the movement that they know causes them pain. In addition to this example, constant swapping from the right to left lead and back again is another common sign that a horse is attempting to bring comfort to their back and failing to do so. Of course the most severe clinical sign of Kissing Spines and other back-related conditions is avoidance behavior or, in other words, bucking and throwing the rider. “When you look at a back x-ray on a standing horse with no rider, you may be seeing close dorsal spinous process space. The space is close or the bones are actually touching. Then, when you add 150 pounds or more with tack and rider, it can make the spine flex downward and those bones are really coming together now,” explains Dr. Honnas of how a rider can exacerbate the pain experienced by horses with Kissing Spines.

While the clinical signs of Kissing Spines can be ambiguous, Dr. Allen is quick to point out that not all horses with radiographic evidence of the condition display outward signs. “It’s often a question of when this condition presents or if it presents. If we’re talking about a western pleasure horse or a horse that doesn’t ever jump over 2 feet 6 inches in its life, the animal may have Kissing Spines and never present. A look at the data on hundreds of horses with back pain revealed that the average age of presentation of back pain was about 6.5-years-old.”

While horses may be genetically predisposed to Kissing Spines and present clinical signs on an x-ray as early as 2-years-old, there are a great number of factors that go into determining if that horse will ever become clinical, including its level of training and specific discipline. Horses performing a sport that requires a high amount of flexing and bending of the back will oftentimes have increased odds of developing clinical symptoms of Kissing Spines in comparison to low-impact or more leisure-based sports — think of a cutting horse versus a horse primarily used on the trail. “A common situation is that we’ll see a horse come in for a pre-purchase exam, and since we’ll routinely do a back x-ray now, we’ll often see some degree of Kissing Spines,” says Dr. Honnas of a frequent and tough place that equine veterinarians find themselves in with potential buyers. “This could mean that space between those bones is reduced but very often not actually touching or overriding. We can also see horses that have tremendous Kissing Spines on an x-ray, but clinically are virtually normal and have no history of back pain. It makes it very difficult to decide on a pre-purchase exam what to recommend to the potential buyers in terms of their risk. This can be a top-end horse, doing its job well and with no disability. We’ll pick up Kissing Spines to some degree on the x-ray, and it’s impossible to state with certainty that horse’s risk of developing symptoms in the future.”

One of the critical first steps in identifying a Kissing Spines case is for a veterinarian to perform a comprehensive whole-horse examination. Dr. Kent Allen performs a back exam.

Physical and Movement Evaluations

The critical first steps in identifying a potential Kissing Spines case, or any other back condition for that matter, is for veterinarians to perform a comprehensive whole-horse examination, then evaluate the horse’s movement and behavioral tendencies. “When we’re doing a lameness or soundness evaluation, every horse gets their back and sacroiliac area palpated in a specific manner,” says Dr. Allen. This allows him and his team to get a valuable baseline to determine when they need to escalate their diagnostics or treatment options for that horse. As part of their clinical evaluations, Dr. Allen and his team like to see the horse lunged on both a firm and soft surface. In addition, they gain important insight by watching the horse under saddle, as long as there is no history of avoidance behavior and the horse has not attempted to throw its rider in the past. If there is a history of avoidance behavior, Dr. Allen will place a weighted surcingle on the horse to evaluate it for back pain without the risk of injuring a rider.

Dr. Williams and his team take a similar approach when confronted with a case that could be experiencing a condition of the back, including Kissing Spines. “I try to focus on the horse as a whole rather than zeroing in on just the suspected problem,” explains Dr. Williams of his whole-horse approach to diagnostics and treatment. “Seeing the animal as a whole allows me to put it all together and avoid jumping immediately to the possibility of Kissing Spines when something else entirely could be at play.” Dr. Williams and his team at Equine Sports Medicine of Maryland observe the horse moving in-hand, then on a lunge line as part of their physical and movement evaluation. “I don’t like lunging as a form of exercise for a lot of these horses, but for diagnostic purposes, it’s good because of its ability to highlight shape and movement. The normal horse should be shaped like a banana around the person lunging them. If they go into a counter-bend as they’re being lunged, that usually belies the fact that their back could be an issue.” Dr. Williams also watches for the natural spring-like motion of a horse’s back as it’s lunging, rather than a straight and stiff board-like movement that could indicate back pain. Dr. Williams, like Drs. Allen, Story and Honnas, is cautious when it comes to observing the horse under saddle out of respect for the rider’s safety. “I like to watch the horse’s behavior during the saddling process and as the rider gets on. I also make a point to look at the saddle in case there is any rocking, bridging, or other issues that can be contributing to the horse’s signs and behavior.” Being a diplomate of the ACVSMR (American College of Veterinary Sports Medicine and Rehabilitation), a key component of Dr. Williams’ evaluation focuses on symmetry, specifically how the horse is using its body, especially in the neck, back and pelvis. “The symmetry of those structures and the muscling can tell you a lot about how long a horse has been having an issue. There can be a change in the muscling and by palpating, manipulating, and doing certain mobility tests with the neck, back, pelvis, and the limbs, I can better gauge the situation.” To help accomplish this, Dr. Williams uses a sternal lift to flex the horse, moving through each section of the back, including the thoracic, thoracolumbar junction, and lumbar regions. He finishes by flexing, then extending the pelvis and performing a lateral motion that gently causes the horse to turn by placing a hand behind the withers on the opposite side of the back, then pushing the pelvic region to twist the horse away from himself. “For horses that have a problem, this method will highlight it,” he explains of the technique.

Blocking can be another tool sometimes used during a veterinary evaluation looking for back issues. Dr. Williams chooses not to block due to the proprioceptive nature of the muscles in question. “There are some people that will go in and put in anesthesia on either side of those areas and see how the horse does after that. One of the biggest reasons I don’t do that is the muscles that directly line the spinous processes are called the multifidus muscles and are known to be proprioceptive, meaning they have a lot of nerve endings and dense fascial planes in them. I’m reluctant to go in and block in the back area because I don’t want to affect the proprioceptive part of that horse’s back. If you do that, you can change how that horse is exhibiting signs by changing the proprioception and not necessarily the pain,” he explains.

Diagnostic Imaging

Following a thorough whole-body physical examination and a more specialized motion evaluation, the next step in a suspected case of Kissing Spines is to confirm the diagnosis with imaging. Drs. Honnas, Story, Williams, and Allen are all significant proponents of the importance of those initial examinations prior to performing imaging. “I tell my clients, ‘I can x-ray your horse’s back and look for things like Kissing Spines, but that could be just a tip of the iceberg,’ ” says Dr. Williams. “That comprehensive evaluation is absolutely necessary to form a complete picture.”

There are two primary diagnostic imaging methods that deliver the clearest picture — literally and figuratively — when dealing with a potential Kissing Spines case. “I teach combined imaging using x-ray and ultrasound to look at as much of the tissue as possible,” says Dr. Williams of his approach. While Kissing Spines can oftentimes appear clearly using x-ray alone, the use of this combined imaging approach delivers the most definitive diagnosis possible. “Ultrasound is the most sensitive tool to observe surface detail. It reflects off of bone. You can’t see through it, but if the bone surface is uneven, it will tell you that. On an x-ray or a radiograph you can’t pick that up unless you get the perfect view,” says Dr. Williams of one reason he brings ultrasound into the equation. Another attribute of ultrasound is its ability to look at the supraspinous ligament, multifidus muscles, and the facet joints, which are placed further down at the base of the spinous processes. “I talk about ultrasound surveys,” says Dr. Williams. “I don’t just look with the ultrasound, then find something and walk away. I survey the back from the withers all the way back through the lumbar region. This gives me all of the information, and I can then better determine whether the horse has Kissing Spines alone, if the case is surgical and if there’s something else at play in addition to the Kissing Spines.”

Could Arthritis Be at Play?

With the prevalence of Kissing Spines increasing, Dr. Allen is quick to caution both practitioners and horse owners to consider the role that arthritis could be playing in the back. “There are horses that have Kissing Spines, horses that have arthritis of the articular processes, and horses that have both,” he says plainly. Articular process osteoarthritis impacts the structures that are deeper into the back by two to three inches. This makes the imaging process both intricate and technical. Dr. Allen, like Dr. Williams, equates the diagnostic challenges of the back to an iceberg. While Kissing Spines may be the tip of the iceberg and easy to spot at the surface, significant problems could be lurking deeper beneath the surface, such as arthritis, requiring a much more concentrated look to properly diagnose and treat the horse.

You can read the other parts of this series here: Part 1, Part 3, and Part 4.

by Jessie Bengoa,

Platinum Performance®