in chondrodystrophic breed , the nucleus pulposus starts to degerate early in life and by one year of age , it has largely replaced by dry , grey/white or yellow degerate , cartilaginous material , which has become mineralised
in other breed , the normal nucleus pulposus persists at least until middle age , although become dry and more fibrous with advancing age , it seldom become mineralised.
a prolapsed disc is a generic tern for any type of cord compression due to the disc
type 1 : extrusion – the centre of the disc herniates into the spinal canal and impinges on the cord causing compression by a mass effect.
-more acute situation
– confined to the chondrodystrophic dogs ( Dachshund, Bulldog, Corgi, Pug, French Bulldog, Bassett Hound, Pekinese, Lhasa Apso, Shih Tzu, Beagle, and Poodle )
type 2: protrusion – a bulging disc that has not burst but presses on the cord
-waxing and waning
-more chornic situaion
-hard to do surgery on
– seen in other dogs
type 3 : the disc material shoots out and hits the cord but is itself liquid and disperses around the cord ( low volume , high velocity )
-small amount of disc material comes out quickly
-eg traumatised in car accident /heavy exercise
– not a space occupying lesion – *does not casue compression*
surgery may or may not help