C6 / C7 changes - Long Term Care

[kwpn_01]

Mine wasn’t so much arthritis but bone cysts present between C6/7 that would have, over time, become arthritic. Found them in my WB mare at 3 y/o after starting light under saddle work. Presented itself as a NQR hind end lameness that would shift legs depending on the direction of travel. Radiographed everything, performed multiple ultrasounds to ensure it wasn’t actually the hind end. A bone scan pointed us in the right direction and cervical x-rays were taken to pin-point the issue.

Unfortunately, we did not have good results. Injected at facets C3-7 both sides, performed shockwave, Osphos and plenty of time off in the pasture. Re-starting her this year identified the lameness had not gone anywhere and a new cyst was developing. We made the very tough decision to retire her as a surrogate broodmare.

[mvp]

Do y’all know about the C6 and C7 malformation that has been found?

Here’s a link to some basic information about it. Sharon May-Davis is the main researcher who has worked on this. I live in Aiken, SC where some nerdy-interested Horsers who had weird neck problems to diagnose started looking at the bones of horses who had had clinical signs, were euthanized, their bodies composed, and then skeletons studied.

The malformations are not of the facet joints, but on the parts of the spine related to the muscle attachments on the underside of the spine where the little muscles going between vertebrae. Apparently, if you can get someone to x-ray C6 from the right angle, you’ll learn what you need to know about malformations in both joints. In other words, C7 won’t be malformed unless C6 is. The condition is congenital.

I brought this up not to confuse things-- and I am confused a bit, as I’ll describe below-- but to ask if the malformation ends up reducing stability in the spine enough that that problem invites future arthritis in the facet joints or even enough movement that the spinal cord is impinged upon.

My confusion: Are all y’all discussing OA in the facet joints, impingement on the spinal column inside or are those related?

My weird data point: I have an Arabian/WB who has some bad OA in the facet joints of her neck. She did get cast in a stall about 5 years ago and it looks to have been a train wreck of a situation, so she could have hurt her neck then. Being Ay-rab, I think she also has a relatively weak base of her neck, though she looks more WB and less Arabian at that part of her body. Still, this mare is wiggly and can drop her thoracic sling in a single foot fall. I have ridden other Arabians who were the same way.

Her facet OA has been maintained really well for the past six months (since we discovered it) with joint injections (Betamethazone was the steroid used) and Tildren, which the vet said would extend the efficacy of those. The mare has built so much more muscle since then, and she’s happy in her work.

I have not x-rayed her neck to look for a C6/C7 malformation, but I would. Those do come in varying degrees, so I imagine that the amount of instability caused there by having muscle scars that are larger or smaller also varies. I’m curious to know if that congenital problem creates a biomechanical one that then shows up way later in behavior ways.

If you guys are ever in Aiken, google up “The Bone Room” or check out their FB page: https://www.facebook.com/EquusSoma/. You can go put your actual hands on some of these actual deformed vertebrae, and also learn some spinal anatomy that is helpful the next time you are attending a vet appointment with your Neck Horse.

[TBKite]

I just learned about that recently. I linked it above. I’m floored by how common it seems to be. It did make me wonder how often they are asymptomatic.

[Peggy]

@TBKite

I just learned about that recently. I linked it above. I’m floored by how common it seems to be. It did make me wonder how often they are asymptomatic.

My vet has thrown out a one in three figure based on a sport horse client base. We recently had a discussion about it and he said he’d read something trying to defend it as an advantage of some sort, but couldn’t recall the details. We then moved on to the fact that breeding for passage-ey trots is probably also selecting for neurological deficits.

[mvp]

@TBKite

I just learned about that recently. I linked it above. I’m floored by how common it seems to be. It did make me wonder how often they are asymptomatic.

I think this is going a bit like ulcers did once endoscopy got cheap: We discovered a huge prevalence of them.

And this also might be the way navicular disease (or, really, the look of a normal vs, pathological navicular bone) changed when we went from film xrays to digital ones. And the people notices that lots of WBs had bad-looking navicular bones without clinical signs of pain.

From the malformations I have seen-- not only to the cervical vertebrae but also to the ribs up front-- I think there’s enough variation in there that horses don’t lose the same degree of biomechanical stability in all cases. And then again, so many horses do or don’t have jobs that require the same use of the neck or thoracic sling or whatever muscles are involved. So it’s a very messy set of kinds of causes of symptoms and degrees of those deleterious boney anomalies.

[TBKite]

I’ve heard a neurologist one the same thing wrt people looking the look of slightly neurological movement. From the webinar it sounds like the c6/7 malformation is most common in TB’s, though is increasingly rapidly in WB’s, and is present in the skeleton of Eclipse (though no one can be completely certain all of the bones of that skeleton are really him). She also mentions being warned not to publish the affected TB bloodlines if she didn’t want to die in a suspicious car accident.

[Peggy]

I have friends who have had over 2/3 of the horses they vetted show radiographic signs of malformation there. These are warmbloods.

My prediction is that eventually the insurance companies are going to have enough and start requiring neck rads as a condition of insurance unless one wants the neck excluded. At that point it may become worthwhile for breeders to eliminate any lines that seem to carry it, assuming it’s known. And I’m pretty sure it’s known in WB and TB, assuming there are clear trends. One problem is that it may not show up, even radiographically until a horse is 4-5 years old.

There was a thread on here a few years ago where people posted photos and pedigrees of their horses with neck issues. It focused mostly on TB lines IIRC.

[Jealoushe]

Is this a genetic thing? Is there any common lines being observed with effected horses? I have seen a horses x ray recently who had an extra boney attachment behind the skull by the vertebrae. Wonder if it would be a similar type of condition.

[Jealoushe]

Oh I would love to see this thread!

[TBKite]

The C6/7 malformation is present and radiographically visible from birth. It can even be found in stillborn foals. It is definitely present in a lot of WB’s now, too, I’m not denying that. It’s possible we’re talking about different issues, though. I’m talking about ECVM.

Jealoushe, I put two links pertaining to the disorder in talking about upthread.

[Jealoushe]

Ok thanks, I had them open and saved to read next!

[Peggy]

The discussion came up, in part, because of a friend’s horse who had some sort of malformation that I’m pretty sure was C6/7. There was something about not being able to check any potential offspring until they were 4 or 5, but maybe that was to check for symptoms. Maybe it’s not easy to see on radiographs until 4 or 5, though it would be possible to see on a necropsy.

Definitely true that there are a lot of different neurological things that seem possible so it’s quite possible I got something confused. Also true that a small difference in the neck can make a big difference in the horse. I wonder if there is some overlap, with some horses being affected more than one way.

I had a conversation with a dressage trainer and breeder close to 20 years ago where he noted that breeders were probably inadvertently selected for neurological deficits in order to get that passage-y trot. That was in dressage bred horses; however, it now seems to be creeping into the jumping lines as well.

[Peggy]

@Jealoushe

Oh I would love to see this thread!

I made an attempt to find it. If we still had the old board that was Googleable I probably could, but the search function within the board doesn’t seem to be terribly robust.

[TBKite]

In ECVM part of c6 is missing on one or both sides. Sometimes the missing piece is instead attached to c7. As long as the vertebrae are mineralized enough to show up on radiographs, ECVM should be apparent. There is a technique described for taking a slightly oblique view to superimpose the area of interest over the trachea to make it easier to see.

[Jealoushe]

That video and article were very informative and interesting. Thanks for linking. I had heard of this but didn’t look into much before but I am going to put it away as a mental note for assessing horses in the future.

[Peggy]

@TBKite

In ECVM part of c6 is missing on one or both sides. Sometimes the missing piece is instead attached to c7. As long as the vertebrae are mineralized enough to show up on radiographs, ECVM should be apparent. There is a technique described for taking a slightly oblique view to superimpose the area of interest over the trachea to make it easier to see.

Yes. What I heard was second or third hand on this horse so something may have gotten lost in translation. But there was definitely something about not knowing some aspect of if it had been passed on to the offspring until they were 4 to 5 years. But maybe it wasn’t ECVM. The horse I euthanized when he was seven may or may not have had ECVM. There were no oblique views done. Also, there was enough going on with his neck that it may not have been possible to see anything subtle through the rest of the stuff that was going on.

This paper describes the radiographic technique: https://d9bfa3f4-7149-4eec-95f7-aa526b073382.filesusr.com/ugd/c73cb2_67b82829d36440a9a31a1987d96a7131.pdf

[Old_Mac_Donald]

I have a couple of questions, and I apologise in advance if they have already been answered:

1. Is it possible to have malformations with NO neurological symptoms, but instead only behavioural (horse won’t ‘round up’ to keep it simple, but is extraordinarily sure-footed and can jump clean and safe)?

2. If you have/had/know of a (1) horse (poor behaviour, no neuro), were you able to improve the horse’s behaviour by treatment (i.e. removing a source of pain) or did you find that the behaviour was linked to the horse being physically unable to perform the task, rather than the task causing pain?

3. I know that this often affects swan-necked or long-necked horses, but what about short-necked cresty ponies, or Iberian breeds?

4. Has anyone ever found changes at C5-C6-C7 level on an x-ray… and yet the horse showed no symptoms or behavioural issues?

[beowulf]

The C6/C7 malformation has been documented as present in all sport-bred breeds that share the same ancestry as TBs and WBs. I don’t believe there is any data suggesting it is more prevalent in one breed or registry vs other. It came from a shared ancestor of both breeds. TBs have it. WBs have it. ISHs have it.

Of studies presented so far for peer review, it appears there is not a reliable observable clinical correlation between the presence of malformation and the horse’s performance.

It goes without saying the malformation is different than things like OA, cervical arthritis, even ECVM or totally missing processes, etc.

Regarding that scandalous “doesn’t want to publish the affected TB bloodlines if she didn’t want to die in a car accident”… um… Bugaloo bungus. It’s ubiquitous in TBs just like it is in WBs. The malformation is older than the TB registry.

[Jealoushe]

That article and video shared has all these answers… worth the time to check out.

[Jealoushe]

That video shared showed photos and videos of horses and how it did effect their performance. Race horses, dressage, eventers, etc.

They also said it goes back very far so it’s too intertwined in the blood lines now to get out.