Hemivertebra

What is Hemivertebra?
Hemivertebra are abnormally shaped backbones (vertebra). Most are in or near the tail of dogs with short "screw" tails, such as the Bulldog's tail. In fact, it is these abnormally formed vertebra that cause the tail to curve. Besides these vertebra, the thoracic vertebra, above the ribs, are often affected. If the curvature is severe, it can compress the spinal cord and cause paralysis in parts of the body behind that region.

How does my dog get Hemivertebra? 
The condition is hereditary, and seems to be part of the set of genes that cause dogs to be flat-faced and screw tailed. During development, the right and left halves of the vertebrae don't fuse as they normally do, and the two halves grow unequally. This causes a curve in the vertebrae, and a curvature in the spinal column. If the curvature is extreme, it may compress the spinal cord that runs within it, causes neurological problems.

How do I know if my dog has Hemivertebra? 
In most cases the hemivertebra don't cause any problem and you will never notice them unless your dog is radiographed. In some cases, however, the spine is curved so that the spinal cord is compressed. Such dogs will usually show signs as puppies, starting around 3 to 4 months of age. They may have a wobbly or abnormal gait progressing to hind leg weakness.  In severe cases the rear end becomes paralyzed.  Your veterinarian will feel along the spine and take radiographs, which will show the deviated abnormal spine. More advanced imaging with MRI and CT scans is needed to see if the spinal cord is compressed.

What can I do about Hemivertebra?
Minor cases require no treatment. In cases in which the spinal cord is only compressed off and on, corticosteroids to reduce inflammation may be sufficient. In severe cases surgery to correct the deformity and take pressure of the spinal cord may be needed.

Is there anything I can do to prevent my dog from getting Hemivertebra?
There is nothing you can do to prevent the condition from occurring, except possibly to refrain from breeding severely affected dogs and to choose your dog from a family without severely affected dogs. Avoiding the condition altogether may not be possible when dealing with breeds with screw tails. 

Are there certain breeds that get Hemivertebra more often?
Flat-faced breeds such as Bulldogs, French Bulldogs, Pugs and Boston Terriers are most likely to be affected. However, the condition has also been seen in German Shorthaired Pointers and Yorkshire Terriers.