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Hemivertebra
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What
is hemivertebra?
This is a
condition where there is abnormal bony development of one or more of
the vertebrae - the bones that make up the spinal column. The main part
of each vertebra should look like a spool when seen from the side. A
hemivertebra looks like a wedge or triangle. Hemivertebra can occur in
dogs that have other kinds of vertebral malformations as well. Whether
the condition causes problems for the dog depends on what part of the
spinal column is affected, and whether there is compression of the
spinal cord.
How
is hemivertebra inherited?
The condition is
autosomal recessive in the German short-haired pointer and German
shepherd. The mode of inheritance is unknown in other breeds.
What
breeds are affected by hemivertebra?
Hemivertebra
occurs in the German short-haired pointer and the German shepherd. It
is seen most commonly in screw-tailed breeds (Boston terrier, bulldog,
French bulldog, and pug), where the kinked tail is the result of
hemivertebrae in the tail region.
For many breeds
and many disorders, the studies to determine the mode of inheritance or
the frequency in the breed have not been carried out, or are
inconclusive. We have listed breeds for which there is a consensus
among those investigating in this field and among veterinary
practitioners, that the condition is significant in this breed.
What
does hemivertebra mean to your dog & you?
A hemivertebra
does not necessarily cause problems for your dog, unless it causes
compression of the nerves (the spinal cord) within the spinal column.
This may occur in two ways - the abnormally shaped vertebra may put
pressure on the spinal cord directly, or it may be an unstable "weak
link" in the vertebral column. Spinal cord compression causes back
pain, weakness or inability to get up or walk, and usually requires
surgery.
How
is hemivertebra diagnosed?
Radiographs
(x-rays) are necessary to diagnose hemivertebra. Your veterinarian may
discover that your dog has hemivertebra while taking x-rays for another
purpose. If your dog shows signs of spinal cord compression (back pain,
weakness, or inability to get up or walk), special x-ray techniques
(such as a myelogram) will show if the compression is caused by a
hemivertebra.
How
is hemivertebra treated?
Unless your dog
has spinal cord compression, there is no need to treat hemivertebra.
Where there is spinal cord compression, your dog will probably need
surgery.
Breeding
advice
It is best not
to breed affected animals. Parents of affected German shepherds and
German short-haired pointers are carriers of the trait and should not
be bred again.
FOR MORE INFORMATION
ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.
Resources
Bailey CS, Morgan JP. 1992. Congenital spinal malformations. Veterinary
Clinics of North America Small Animal Practice. 22(4):985-1015.
LeCouteur RA, Child G. 1995. Diseases of the spinal cord. In EJ
Ettinger and EC Feldman (eds.) Textbook of Veterinary Internal
Medicine, pp. 629-696. WB Saunders Co., Toronto.
This database is a joint initiative of
the Sir James Dunn Animal Welfare Centre at the Atlantic Veterinary
College, University of Prince Edward Island, and the Canadian
Veterinary Medical Association.
Copyright © 1998 Canine Inherited
Disorders Database. All rights reserved.
Revised: April 23, 2002.
Permission to reprint is granted by
Alice Crook, DVM Coordinator, Sir James Dunn Animal Welfare Centre
Atlantic Veterinary College University of Prince Edward Island
The above information is simply informational. It's intent is
not to replace the advice of a veterinarian nor to assist you in making
a diagnosis of your pet. Please consult with your own veterinarian for
confirmation of any diagnosis. Your pets life may depend on it