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By: Dr. Lydia Gray, SmartPak Medical Director/Staff Veterinarian
Officially known as “overriding dorsal spinous processes” or “spinous process impingement” this term describes the touching or “kissing” of the long, thin bones that project upward from the vertebrae of the spinal column in the horse’s back. These bony prominences start at the horse’s withers with the first thoracic vertebra (T1) and continue to the point of the hip with the last lumbar vertebra (L6), with T13 – T18 being the most commonly affected. In fact, most Kissing Spines are seen between T14 - T15 and T15 - T16, where the slant of the spinous processes change direction from a slight angle backward to a slight angle forward. This is also directly underneath where the rider sits.
In this radiograph, the dorsal spinous processes are in alignment with roughly equal spacing.
There are several reasons why a diagnosis of Kissing Spines in horses can be challenging. First, not every horse with spinous process impingement on X-ray shows acute back pain. Second, there is no one clinical sign that clearly points to Kissing Spines as the cause. Rather, the horse’s trainer, owner, and veterinarian must work together as a team to identify behavior, performance, and discomfort issues that together tell a story of primary back pain. Third, some indications that a horse may be dealing with Kissing Spines are subtle and may be interpreted as behavior or training issues. Here are examples of some of the signs that have been identified in horses diagnosed with this condition:
With a long list of behavioral, performance, and soundness signs possibly pointing to Kissing Spines in horses, it’s important to confirm the condition or rule it out in order to start appropriate treatment. The diagnosis of any disease or condition starts with the veterinarian taking a complete history, which means sitting down with the owner and trainer and talking through their observations. Signalment – or age, breed, gender – is also critical to forming a diagnosis. Next, the vet performs a complete physical examination of the horse that includes hands-on palpation of the entire body, including the back. A thorough and systematic lameness exam follows, and may include observing the horse while in motion in-hand, on the lunge-line, and under saddle, as long as it is safe. Some vets perform a nerve block (ie inject local anesthetic) in the back area and repeat the lameness exam, but this may not be a reliable test for Kissing Spines. Radiographic images (X-rays) are considered the gold standard for confirming this condition, with nuclear scintigraphy (bone scan), thermography, and ultrasound also contributing valuable information that can be helpful in formulating a treatment plan.
Treatment of Kissing Spines starts with making the horse more comfortable, followed by a program of physical therapy to strengthen back and abdominal muscles, stabilize the posture, and improve mobility. Relieving the pain associated with Kissing Spines can be approached medically or surgically, and before recommending the best options for a particular case, the veterinarian will take into account many factors, such as:
Unless the Kissing Spines is very advanced, most veterinarians will likely recommend starting with a conservative, medical approach to the treatment of this condition. Methods to control the pain and inflammation and therefore break the muscle spasm cycle and restore motion include:
SmartPak strongly encourages you to consult your veterinarian regarding specific questions about your horse's health. This information is not intended to diagnose or treat any disease, and is purely educational.