Page 90 - September 2020

EQUINE HEALTH
With wobblers, as long as the vertebrae are still growing, there is still opportunity for correction. But once these horses become yearlings, or older, chance for recovery are slim without surgical fusion.
knuckled forward), we may have to resort to cutting the tendon involved--either the deep flexor tendon in coffin joint flexural deformi- ties, or the superficial flexor tendon and/or the suspensory ligament in horses with fetlock flexural deformities,” says Schramme.
In these cases, you are more or less giving up on them ever being a useful athlete. You are just looking toward salvage, such as a breeding animal. “As long as you are just cutting check ligaments, you preserve the athletic potential; if you are cutting tendons, you are giving up on that potential. There are always exceptions, but this is a good generalization.”
WOBBLERS
Just like osteochondrosis, wobbler syndrome is mostly due to abnormal bone formation; the ossification of growing cartilage does not prog- ress properly in the vertebrae of the neck and the vertebrae become misshapen, resulting in pressure on the spinal cord. “In some instances, signs start as early as weanling age,” says Schramme. “Early recognition may sometimes be an advantage. Some research suggests that
if the growth process can be slowed down, the condition may correct, since the vertebrae are not completely ossified yet at that age.
“If a weanling starts moving noticeably wobbly behind, radiographs should be taken to examine the neck. Confinement of such cases to a stall may prevent any further damage to the spinal cord. In combination with dietary changes aimed at slowing down the young horse’s growth rate, some cases will improve
or even become normal again. If you slow the growth, and make sure the ration is balanced for calcium and phosphorus (with adequate copper and vitamins) and eliminate carbohy- drates as much as possible, this may help.”
He says that wobbler syndrome only becomes irreversible when the vertebrae have taken on their final mature shape. As long as the vertebrae are still growing, there is still op- portunity for correction. But once these horses become yearlings, or older, chance for recovery are slim without surgical fusion.
Schramme says there are two forms of spinal cord compression that can result in Wobbler Syndrome. He calls one form dynamic cervical compression, where pressure on the spine is inter- mittent depending on the position of the horse’s neck. This form tends to occur higher up in the neck, at the third or fourth cervical vertebrae, and is more commonly seen in young horses less than three years of age. The other form he calls static
cervical compression, which results in continu- ous spinal cord compression. This form tends
to occur farther down in the neck at the level of the fifth, sixth or seventh cervical vertebrae and is seen mainly in horses five years old and older. With either form, the disease is irreversible when the vertebrae have formed and the damage to the spinal cord has been done.
Treatment is varied. “Many of these horses can be greatly improved by fixing two adjacent vertebrae in the neck at a set angle. By stabiliz- ing the vertebrae at the level of the spinal cord compression in a neutral angle, pressure on the cord can be greatly reduced or eliminated. This immobilization is achieved by putting a metal basket between the two adjacent vertebrae, thereby eliminating all movement between them. We can now screw them in, so they are locked in more solidly. In the earliest efforts to do these corrections, we had to just hammer them in, and they sometimes fell out,” he says.
The screwed-in baskets were named after Seattle Slew, the 1977 Triple Crown winner who suffered from Wobbler Syndrome in his old age. Dr. George Bagby, a human spine surgeon from Spokane, Washington, was instrumental in this innovative device. Bagby received his orthopedic training at the Mayo
Today there are many ways to help a veterinarian diagnose wobbler cases, such as doing neurologic exams, taking blood samples, radiographs or myelogram.
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