Back pain in Horses – Part 2 – Back Pathologies
The most common pathologies that you’re horse is likely to be diagnosed with are:
- Bony Changes
- Kissing Spines or Overriding Dorsal Spinous Processes
- Arthritis of the facet joints
Actually they are all really the same thing, just at different stages, except the facet joint arthritis, which is inflammation of the joint.
Kissing spines is the colloquial term for the condition Spondylitis. Which is inflammation and the formation of new bone of the thoracic and lumbar vertebrae, commonly found between T13-T18 where the saddle is positioned.
Although it is rare to find the condition in the lumbar area. It is thought that long existing inflammation of the interosseous ligament that connects the dorsal spines and causes new bone to form and reduces the spacing which can eventually lead to the touching (kissing) of the spinous processes.
Ankylosing spondylitis is the formation of new bone on the underside of the vertebrae. Both conditions are painful whilst actively progressing but once the bone has formed, fused and settled the pain is relieved.
In the x-ray picture below, you can see on the red arrow where the bones has rubbed together so much, they almost create a jigsaw effect. The green arrow shows typical bony changes and active bone formation around the spinous processes.
What causes kissing spines?
- Sub-optimal confirmation
- Foot balance
- Poor Posture
The thoroughbred is a breed that has a high number of diagnoses for kissing spines, with some quoting up to 55% of reported cases of kissing spines believed to be either thoroughbred or thoroughbred cross. One possible explanation for this could be due to the racing industry’s requirement to break horses before the skeleton has fully fused. Typical growth plate fusion starts from the ground and works up and the estimated time frame would be:
- Spinous process fuse at around 4-5 years
- Tuber coxae, tuber sacrale and tuber ishium – 3-4 ½ years
As racing thoroughbreds tend to be broken at around 18 months old its plausible that damage and weakness especially in the thoracic spinal area is likely. It is also believed that the hard fast work and the types of saddles used in racing also have a negative impact on the thoroughbred’s conformation and posture which can then lead to the diagnosis. It is also thought that there is a genetic predisposition in thoroughbreds that makes them more susceptible.
Come back next week for Part 3 – Where we’ll look at recognising pain sign