Intervertebral Disc Disease
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Which breeds are most likely to
be affected with Intervertebral Disc Disease?
By far the most commonly affected dog is the
Dachshund. However, the Shih Tzu, (along with Pekingese, Lhasa Apso, Welsh
Corgi, and the Beagle) are also commonly affected. This in no way implies that
your dog will be affected; but it is a good idea to have an understanding of the
disease in case your dog is affected.
Spangles, who had successful surgery for a ruptured disc at Davies Veterinary Specialists |
Intervertebral disc disease is a premature hardening of the centre of the disc, and weakening of the outer layer of the disc that occurs in chondrodystrophic dogs such as dachshunds. As the outer layer of the disc ruptures, the inner material is displaced upwards against the spinal cord. This herniated disc material injures the spinal cord and results in cord swelling and compression. Consequentially, the nerves within the spinal cord travelling to the legs and urinary bladder become damaged. This in turn results in loss of limb function that can range from weakness to paralysis, and loss of bladder control.
In some cases, the damage to the spinal cord is minor, clinical signs are mild, and anti-inflammatory drugs such as methylprednisolone can be given to decrease the swelling in the cord and allow function to return. If methylprednisolone is given, the animal may feel better and may want to be active. However, it is extremely important that the dog is strictly confined to prevent further herniation of disc material. In about 4-6 weeks, the rupture heals and the dog can resume normal activity.
In other cases, the amount of disc material compressing the cord is too great and conservative therapy is unsuccessful. These dogs require surgery to remove a section of bone over the spinal cord (hemilaminectomy), and to remove the herniated disc material in order to relieve the pressure on the cord. Before surgery can be done, radiographs (x-rays) and a myelogram (a special x-ray in which dye is injected around the spinal cord) must be performed to identify the area of the spinal cord that is involved. After surgery, the prognosis is still guarded. Unless there has been severe damage to the cord, most dogs will regain some degree of neurological function may and be able to walk.
Some dogs have such severe damage to the spinal cord that they can no longer feel when their toes are pinched and are said to be “deep pain negative.” In this group of dogs the prognosis for regaining use of the legs is very poor. These dogs can still receive decompressive surgery and if the cord appears intact, we can wait to see if the dog regains function. After 6 months, if the dog has not regained function it is highly unlikely that the dog will walk again.
http://www.vetspecialists.co.uk/
Dec 2004 - Scientists Reverse
Paralysis in Dogs
By RICK CALLAHAN, Associated Press Writer
INDIANAPOLIS - Dogs with paralyzed hind legs regained the ability to walk after
getting a shot of a chemical cousin of antifreeze that helped repair nerve cells
in their damaged spinal cords, scientists reported.
Purdue University researchers who led the project hope the approach can soon be
tried in people, but caution that there are significant differences between
human and canine spinal cords.
The treatment only worked on dogs given the injections within about three days
of their injury. Some dogs not given the injections eventually walked again, but
those getting the new treatment had a dramatically higher recovery rate.
In one case, a dachshund named Oscar was initially sent home with a wheel cart
and little hope of recovery after a serious injury.
Soon after the dog got the chemical treatment, he began walking, although his
back legs work in unison, giving him an unusual gait.
"I used to make fun of him, saying he walks like a drunken sailor," said Oscar's
owner, Dan Paulin of Boonville, Ind. "I don't think he'll ever be normal, but at
least he's not confined to the wheel cart."
In the study, 19 paraplegic dogs were injected with polyethylene glycol, or PEG
- a nontoxic liquid polymer composed of long strings of the same type of
molecules found in antifreeze.
Within eight weeks, 13 of the 19 canines, about 68 percent, regained the use of
their hind legs and were able to walk, some almost as well as before their
injury.
The dogs were injected twice with PEG, first soon after their owners brought
them to the researchers' labs and then after standard surgery and steroids to
reduce inflammation.
Among a group of 24 dogs that received just the standard surgery and
rehabilitation therapies, only about 25 percent regained the same level of
mobility, feeling and bodily functions, with about 62 percent remaining
paraplegic.
The study's findings appear in the December issue of the Journal of Neurotrauma.
Scientists at Purdue, Indiana University's Indianapolis campus and Texas A&M
University took part in the research on dogs ages 2 to 8 between 2001-03.
Richard Borgens, the Purdue professor of neuroscience who oversaw the study,
said his West Lafayette, Ind., lab had previously used PEG to repair damaged
spinal cords in guinea pigs with about a 90 percent success rate.
His team has even fused severed guinea pig spinal cords using PEG, although the
dogs in the study had spinal disc ruptures that crushed, but did not sever,
their spinal cords.
Although exactly how PEG works remains unclear, Borgens said it appears to act
as a sort of "molecular Band-Aid" that forms a temporary seal over breaches in
nerve cells in the spinal cord, aiding their healing process.
"This stuff is kind of like a radiator stop-leak for the nervous system. The
polymer spreads out and forms a seal over the damaged areas in the nerve cells
and allows the membrane below to reconstruct itself," said Borgens, director of
Purdue's Center for Paralysis Research.
He said PEG also appears to prevent secondary tissue death that often causes
more damage than the original injury. Borgens said the agent only covers damaged
cells and tissues when injected into the blood stream.
Purdue has enlisted a yet-to-be-announced corporate sponsor that will make PEG
in a form suitable for human clinical trials. Pending federal approval, Borgens
hopes those trials can begin within about 18 months on people with hours-old or
days-old spinal injuries.
W. Dalton Dietrich, the scientific director of The Miami Project To Cure
Paralysis, said the rapid improvements in the dogs are intriguing, but point to
the need for follow-up work to learn more about how PEG works and evaluate its
safety. "Although the results are very provocative, additional studies are
required," he said.
Karen Kline, an associate professor of neurology and neurosurgery at Iowa State
University's College of Veterinary Medicine in Ames, Iowa, called the findings
promising. She said PEG, which she plans to test on dogs at her lab, appears to
stabilize damaged tissue to allow more rapid healing than typically occurs
naturally.
"It has such promise, but I think we need to look at more animals and make sure
that we're getting a positive outcome," Kline said.
Purdue Center for Paralysis Research:
http://www.vet.purdue.edu/cpr/