10/12/2024
This is an interesting article. A few years ago I knew a mare who as she got older started to flip over, I mean just flip over for no apparent reason, she would then get up and stand there as though nothing had happened. She had poor muscle in her neck which just didn’t add up with the way she was worked and appeared to be otherwise fit and healthy and pain free. It was always in the back of my mind about malformation of the C6 and C7.
The mare was put down as a result of her flipping over, maybe now, there would have been some way to help her, but at the time there was little information or indeed treatment available.
There has been so much going on around the topic of ECVM, this congenital malformation is one we are diagnosing, managing and studying at Denali Equine in partnership with Rexos Inc, under the guidance of the legendary Dr. Sharon May-Davis. We wanted to give you the top ten points on ECVM facts. (Sorry this is long- Well worth the full read!)
1. ECVM is a congenital condition, meaning they are born with it. We suspect it is a recessive genetic disorder because two unaffected adults can produce offspring with it. There are several groups racing to find the genetics behind this condition. More information on the horizon.
2. ECVM is not a fatal diagnosis. However, it can be. It depends on the severity of the malformation and how well the horse can functionally compensate.
3. Radiographs of the lower neck are necessary to diagnose the condition. These radiographs must be clear lateral and obliques of C6, C7 and ideally T1. These can be done in the field for most horses. However larger generators do get better images.
4. Variability: Horses can be either a bilateral or unilateral malformation of C6, which in 52% of C6 cases can transpose either bilaterally or unilaterally. To C7; T1 and the first ribs are variably affected.
5. Studies show horses with transposition of the ventral lamina to C7 are more likely to suffer from clinical neck pain than horses with normal anatomy. In our experience horses with rib malformations have more severe clinical signs than those with normal ribs (no clear studies yet).
6. The bones absolutely do not tell the whole story. However, bones do not lie. They often indicate the level of soft tissue malformations present. The more severe the boney changes- the more severe the soft tissue is altered around them.
7. Clinical picture: all horses are not lame, but they do all have subtle clinical signs. Most often the clinical signs are not limb related lameness (but can be). These horses can show signs of the pain ethogram, rearing, sporadic behavior, abnormal front limb flight patterns (especially with equipment), girthiness, resistance to go forward, doesn’t like physical touch (brushing, blanketing ex). The signs are so variable for every horse!
8. The common things heard from owners/trainers:
* The horse was always bad from the start (this is concerning for the more severe cases)
* The horse was fine until it wasn’t. We find this is from something changed in the program. i.e., was imported, switched barns, changed jobs.
* They don’t understand why the horse is failing quicker than usual as it gets older. As the horse ages the clinical signs become more apparent. The body can only manage for so long. Think of it this way- the foundation was built wrong from the beginning. Therefore, it takes time for the cracks in your walls or floors to show, it then takes those cracks a while before they become a structural problem in your house.
* A minor incident happened and now they’re not ok. Suspect an injury can cause the horse to spiral out of stabilization or have the ability to compensate. An example could be getting cast or trailering event then the horse was never the same. Example, you do not know your house wasn’t built well until the storm blows it over.
9. These horses have significant soft tissue pathology on necropsies. Therefore, no matter what the data is showing us: If the horse has ECVM, is clinical, and other differentials have been ruled out these horses are clinically affected by the ECVM.
10. On necropsies we have found:
* Missing, malformed and fractured ribs
* Abnormal nerve patterns, these nerves can be totally entrapped and compressed by abnormal muscle patterns. The dorsal scalene can trap the large nerves of the brachial plexus within its abnormal paths. The phrenic nerve can get pulled inappropriately and leave impressions within the ventral scalene.
* Abnormal muscles: dorsal scalene, ventral scalene, iliocostalis, longus coli, re**us abdominal, intercostal muscles, serratus ventails cervicis. All these muscles have critical roles in stability, proprioception, and biomechanics.
* Abnormal vascular patterns
* Trachea abnormalities
* Fascial changes
ECVM is currently a controversial and sensitive topic so we thought we would share a few known quick facts to help you understand this issue better. Please go to our website (www.DenaliEquine.com) to find more information and links to the current studies on this disease. We are researching and studying these horses! We are working on several angles of research right now throughout Non-Profit Rexos Inc. If you would like more information on how you can help, please reach out!
DeClue Equine saddlefitting.us