Front Matter

436 Canine Sports Medicine and Rehabilitation

Likewise, we can, on rare occasions, see dogs
less than 1 year of age with severe signs from
lumbosacral nerve root entrapment. More typi­
cally, these dogs develop nerve root entrapment
at various adult ages determined by the encroach­
ment caused by degeneration and proliferations
of the surrounding ligamentous and sometimes
bony structures that further compromise an
already stenotic spinal canal.
Many of these conditions are highlighted by
dynamic advanced imaging (Figure  17.15).
These conditions are often overlooked when
only static representations are evaluated (Jones
& Inzana, 2000).

Breed‐specific intervertebral disc disease

When Hansen first described disc degeneration,
he made a distinction between the chondrodys­
trophic breeds and non‐chondrodystrophic
breeds (Hansen, 1951). The degeneration that
occurs in both groups of dogs is actually quite
similar, the difference being that in chondrodys­
trophic breeds disc degeneration usually starts
before 1 year of age. The degeneration has a
genetic predisposition in the chondrodystrophic
breeds and virtually all of the discs deteriorate.
The collagen components of the nucleus pulpo­
sus and annulus fibrosus change. This has a
fairly complex epidemiological/genetic distri­

bution as the specific genetic mutation that is

associated with chondrodysplasia is not found

in the Beagle, yet their discs deteriorate in a

similar manner and time frame as those of chon­

drodystrophic breeds. Likewise, although Jack

Russell Terriers are chondrodystrophic, they

seem to have a rather low incidence of interver­

tebral disc disease.

An excellent review of intervertebral disc

degeneration by Bergknut (2011) is available

online.

Degenerative and stress‐related

conditions of the spine

Spondylosis deformans and diffuse

idiopathic skeletal hyperostosis

Spondylosis deformans and diffuse idiopathic

skeletal hyperostosis (DISH) are different dis­

eases. These conditions are often confused but

have been shown to be quite distinct in people

(Resnick, 1985).

Spondylosis is very common bony produc­

tion at the ventral endplates of the vertebrae,

seen as simple prominences to actual bony

fusions without evidence of inflammation

(Figure 17.16). There is very little evidence that

spinal cord or nerve root pathology occurs as a

result of this condition.

(A) (B)

Figure 17.15 (A) Transverse CT with contrast of a normal C6 vertebra. Note the large amount of space surrounding the
spinal cord. (B) Transverse CT with contrast of the C6 vertebra. Note that there no room around the spinal cord and the
spinal cord appears flattened (asterisk). Both figures are at approximately the same level of the spine and both dogs’
heads were positioned similarly. The dog in (B) had significant clinical signs.