Out of interest....navicular

S

spaniel

Well-Known Member
Joined
21 March 2002
Messages
8,277
Visit site
Other posts got me thinking.


Has anyone ever tried to actually remove a damaged nav bone and replace it with something else?? Human medicine can replace bits and pieces so can equine science do the same?
 
I don't think that would be possible for a couple of reasons.

Number 1 - what would you replace it with? Prosthetic replacements in humans are not weight bearing in the same way that the navicular bone in horses is. Number 2 - You could not do a navicular transplant as it would be immunologically rejected and very expensive and difficult to treat with immunosuppressants without the horse going down with any number of viral/bacterial infections, a major side-effect of transplants in humans. Number 3 - you can't explain to a horse that it must not weight bear until the prosthesis has 'taken' unlike humans where you can order them to bed rest for a couple of weeks. Number 4 - The risk of infection in any post-operative wound is very high. In a horse, and particular in the foot, you'd be almost a dead cert for infection long before the horse could return to work.

And the most compelling reason of all? All of the above would be hideously expensive, almost certainly bound to fail, greatly in excess of the value of the horse (even an expensive competition one) and with no guarantee of being any better than before.

Sorry to be so gloomy about it. I do believe that many of the recent veterinary advances are handed down from human medicine and for navicular, I think the new generation of collagen fillers prevalent in plastic surgery may offer new treatments as cushioning but will require a very dedicated vet to get it through the new medication trials process, not to mention the difficulty of balancing the trials with a placebo. Anyway, just my thoughts on the subject!
 
I take all your points and agree both of you. However Im sure that at some point someone will start to try and look into this. The navicular is such a fragile but important little thing. Hopefully one day it will be possible.
 
Having dissected many equine distal limbs I can't imagine such an operation being carried out for the following reasons:-

1. Cost - its right at the heart of the foot and is jolly hard work to get to physically, let alone to remove and replace.

2. Post operative infection risk, very high I would think and given that the hoof surrounds the foot, infection would cause abscesses and require surgical conditions to drain them. And as the foot tends to reside in less than sterile conditions, this risk is higher than it would be for other operations.

3. Success rate, even if it were considered an acceptable investment, you have a variety of tissue types which are close to the navicular bone, would they all accept a foreign replacement?

4. How do you make a horse rest its foot for long enough after such an operation to make it a success?

Sorry to be such a doom and gloom merchant, but I can't see this ever being reality. Also on a more contraversial note, I don't see the navicular bone as being the "problem that needs to be solved" in most cases. I've seen poor navicular bones on x-ray where horse come sound given the right foot care.
 
Would it even be possible to get at the area without permanently damaging the structures of the hoof anyway?

I think they'd be more feasible to lop the foot off and fit an equine version of those special running blades amputees have, rather than replace it's navicular bone.
 
I think stem cell based technology might provide the answer to navicular disease, rather than invasive transplantation. But probably not in my lifetime, unfortunately.

This type of thing:
http://www.livescience.com/health/060509_growing_bones.html
or this:
http://findarticles.com/p/articles/mi_qa3767/is_200604/ai_n16350757/

It'll be years and years before this percolates down to veterinary medicine though
frown.gif
 
From what I understand a good number of cases which are diagnosed as navicular or navicular syndrome are actually soft tissue injuries within the coffin joint. MRI is making diagnosis easier but I still believe there are a large number of horses diagnosed with navicular who actually have other problems.
Agree with the others regarding the cost and risk making it unlikely to ever happen. As Andalucian says most cases can be managed with the right shoeing.
 
I agree with Marchtime, Navicular and Navicular syndrome are catchalls which basically cover all foot pain. Coffin joints, navicular bursa and soft tissue and bad shoeing all block to a very similar point and have the same physical effect on the horse. Navicular as a diagnosis is highly suspect without MRI and as most insurance companies won't stretch to MRI the catchall covers it. Therefore I believe more money should be spent on developing a method for reliable diagnosis of problems within the foot.
 
In my humble opinion MOST cases of navicular are man made, it comes from lack of development of the foot and (not necessarily poor) shoeing.
If we didn't break it in the first place we wouldn't need to fix it!
 
[ QUOTE ]
As Andalucian says most cases can be managed with the right shoeing.

[/ QUOTE ]
I don't think I mentioned shoeing. In my opinion a Navicular horse needs to be shod like it needs a hole in the head.
I'm not anti shoe, but I wouldn't shoe a foot unless I thought it was in a good enough state of health to cope with being shod. There's food for thought.
 
My initial interest was in actually replacing the navicular itself once a definite diagnosis is made. Putting aside the cost involved - whether its actually possible or been tried yet.
 
[ QUOTE ]
My initial interest was in actually replacing the navicular itself once a definite diagnosis is made.

[/ QUOTE ]

The problem with this is -

- horse goes lame
- vet nerve blocks and shows up foot pain
- next step is x-rays
- if changes to the navicular bone are found vet makes a definite diagnosis of navicular. Nobody then bothers with MRI.

Just because there definitely is navicular doesn't mean this is the only only problem, or even necessarily the main problem causing the lameness.

The treatment is the same really anyway - crap, not a cure and only a way of relieving pain until it worsens - heartbars/barefoot.
smirk.gif


Foot problems are soul-destroying.
frown.gif
 
You must log in or register to reply here.
Top