Navicular & Neurectomies

QUESTION: 

Hello there Dr. Teskey,

I'm hoping you can help me out. I've just purchased a broodmare with navicular. Would it be possible for you to provide me with some information before breeding this mare? I took her x-rays to my local vet and she suggesting cutting the nerve on my mare and didn't understand why the previous owner hadn't done it sooner. What are the pro's and cons of this nerve cutting?

Thank you for your time.

Sharon

DR. TOM'S ANSWER:

Hi there, Sharon,

The procedure you're referring to is known as a "neurectomy". It is generally performed on horses that have had chronic pain problems in their feet, most notably "navicular" problems. The horse is put under general anesthesia and the digital nerves on both sides of the lame leg AND the more sound leg are isolated and cut--most often a section of the nerve on both sides is removed. The reason that both legs are surgicated is because most horses end up quite lame in the leg opposite the originally lame one if it is left intact. Thus, one can easily appreciate that even though a horse only shows lameness in one of the forelegs, both are affected in a horse with "navicular" disease or "navicular" syndrome. The result of the surgery is that the horse loses sensation from this point downward and is unable to feel the pain from the diseased foot anymore. Usually the limping that was due to the pain in the area goes away and the horse can continue to be used. The horse is thus returned to "soundness".

This procedure costs anywhere from $250 to $1500 depending on where it is done and who does it. It is "effective" for around one to two years--sometimes not that long, sometimes longer, but all of these horses eventually regrow some nerve connections and regain sensation of the area that was originally desensitized. The lameness then returns and the procedure can be repeated at that time to keep the horse sound.

As you can easily see, this procedure addresses only one thing for the horse and the owner: the head bobbing lameness.

There are some very real and potentially devastating negative side effects of digital nerve neurectomies in horses. Often times the raw ends of the nerves become irritated to the point of developing extremely painful nerve tumors called neuromas, leading to further surgeries to remove them. Other times, the digital arteries and veins that lie immediately parallel to the cut digital nerves become scarred and the resulting stagnation of circulation leads to foundering of the worst degree. Localized infections, scarring of tendinous and ligamentous structures and unsightly swellings are also common. Thus, a procedure designed to provide temporary relief from a widely misunderstood type of lameness often leads to further pain, loss of use and early death for these affected horses. Performing these surgeries is severely disruptive to the horse's lower leg anatomy, physiology and energy patterns, and commonly leads to irreparable damage.

"Navicular" problems, often referred to as "heel pain" or "caudal heel syndrome" start presenting symptoms in horses as young as two and three years old when their hooves are either allowed to overgrow in to a deformed shape and/or their feet shod at this young age. The still-developing coffin bones and sensitive inner hoof structures are surrounded, constricted and over-pressurized by the progressively-deforming hoof capsules, starving them of vital movement and circulation, yet forcing them to attempt to function and survive in a physiologically stagnant state. Older horses are also plagued by what is termed navicular disease and innumerable other hoof problems when their hooves also succomb to deformities in structure and stagnation of function. These lamenesses occur after longer periods of what is traditionally thought to be the "best hoof care possible". When this "best hoof care possible" consists of infrequent trimming and/or shoeing, it is no mystery, but rather a highly predictable and physiologic certainty, that these horses will suffer from hoof deformities and possibly debilitating lamenesses. "Killing me softly" takes on new meanings when it comes to the effects of the steel horseshoe on our equine companions.

Given that all of these "navicular" horses can be shown to have deformities in the outward appearance of their hooves, it would seem logical to direct our efforts towards improving their abnormal hoof form, reversing the trends that are causing these deformities and provide for the horse a situation that promotes good hoof form. Cutting the digital nerves in these horses provides absolutely nothing honesty therapeutic for them. It is a medically unsound procedure, but it is prevalent in our modern day "use and abuse" philosophy of keeping horses--doing this in a day and age where we now have an excellent understanding of why these horses end up with "navicular" pain is totally unnecessary and irresponsible--there are no sound medical reasons to perform these nerve surgeries with the reckless abandon they are. These procedures are an excellent example of how simple ignorance of proper hoof form and function allows horse owners and their veterinarians to perform them. Terms like "salvage procedure" have become widely used to describe such procedures that prolong the useful life of the animal strictly for the human's monetary benefit. Addressing the real problems of the deformities in the feet and how to reverse them with proper trimming and lifestyle will win out as the only acceptable alternative for these animals and their human stewards.

Performing digital neurectomies on heel-sore or foot-sore horses promotes further degeneration of the entire lower leg and hooves in these animals, because it disrespects and disallows what the entire animal needs to achieve a more proper hoof form and normal function. Instead of cutting the nerves to a part of the horse's anatomy and achieving a completely false sense of "soundness", we are alternatively able to nurture these unsound horses and their deformed feet to attain correct hoof form and thus proper and vital physiologic function. Natural exfoliation, vital mechanical hoof movements, energizing sensation and exquisite protection are just a few of the important functions horses' hooves need to have, and this is precisely what they achieve with proper hoof care. This leads us and our horses on a direct path to an honest soundness, far outpacing conventional western veterinary medical techniques and promoting the physical and psychological health of the entire horse rather than disrupting a part of the horse's vital anatomy, which only leads to further deterioration, loss of use and early death.

As it is improperly trimmed and/or shod horses that are the ones affected by "navicular syndrome", we know that promoting sound, naturally shaped hooves along with adequate movement on firm terrain is essentially a life-promoting and life-saving, honesty therapeutic form of treatment--it is the only treatment I will prescribe for horses that I tend to, as it is the only treatment that respects the nature of the horse. Drugs such as isoxsuprine, nitrous oxide, nitroglycerin, phenylbutazone and flunixin meglumine do nothing to improve the deformed feet in these affected horses. Eggbar shoes, reversed shoes, special pads, natural balance shoes, wedge pads, impression material, shoes with rails and/or frog inserts or any other artificial appliance attached to the bottom of the horse can not possibly be honestly therapeutic for horses with navicular problems or other hoof ailments. It is a physiologic impossibility; they can only serve to further the deformities and damage to the horses they are nailed to, perhaps prolonging the development of further, inevitable symptoms until years down the road, but still furthering the damage all the while. There is not a single case of a horse with severe "navicular disease" that has been cured by the application of an appliance to the foot. Cured, and/or sound, would be defined as a horse that is able to walk, trot and run at liberty on their own feet in a soft environment with animation, impulsion and without lameness. It is the promotion of natural hoof form and thus proper hoof function which allows horses to heal from the insults previously afforded them by improper trimming, shoeing and/or lifestyle, and they heal remarkably well if we respect their fascinating anatomy and it's wonderfully simple physiology. Providing this option to horse owners when they are faced with whether to pay for a "salvage procedure" or provide for what their horse honestly needs is what the natural hoof care movement is about. These are life and death situations for our horses and it saves horses lives every day.

It is ironic that honest, well-intentioned people across the land are spending their hard-earned money on treatments that are making their horses more unsound and more unusable in the long run. Terms such as "therapeutic shoeing" or "corrective shoeing" will soon be exposed for the oxymorons they are, and interested parties such as insurance companies and horse-leasing operations will soon question such practices, and will not stand idly by while shelling out millions of dollars to pay for procedures, appliances and treatments that only serve to worsen the conditions of the animals to which they are responsible. Alas, this is the age we now live in...an age of transition for ourselves as well as our horses. Our responsibilities are great, the knowledge is there, and it is coming to an area near you.

Take care,

Tomas Teskey D.V.M.

NOTES FROM GWEN ON TRIMMING:

Decontracting heels can be a timely event even in the best of conditions. Given the correct parameters of the hooves into which new horn can grow decontraction CAN and DOES happen - even for an older horse. From a trimming point-of-view one wants to be sure that the point of weight bearing is balanced in the hoof. If the weight is shifted either too far forward or too far back within the hoof, the incorrect values will affect the contraction of the heels as you're seeing now. As Dr. Tom mentioned, the correct natural environment and lifestyle needs to partner with the trim to provide the adequate surroundings for correction. Learn the correct hoof form until the image of one is embedded in your brain. Educate yourself on the aspects of the natural trim so you will be able to quickly assess what needs tweaking here and there. 

:)  --Gwen