IVDD is a disease that can cause neurological dysfunction, and if it is severe enough it requires surgery. Just like in people the spine is composed of multiple little bones, called vertebrae, which line up to form a bone tunnel, called the spinal canal. Between the most of the vertebrae there is a soft tissue structure called the disc. The disc allows animals to have motion, flexibility and absorb energy. The spinal cord runs through the spinal canal before it disperses nerves off to the rest of the body.

IVDD can either be an acute episode where your pet is fine literally one minute and cannot walk the next or it can happen as a slower more chronic onset, more similar to people. We most commonly see the acute episode.

Certain breeds of dogs are predisposed to IVDD; they are called chondrodystrophic, which are dogs like Dachshunds and others that have longs backs relative to their short legs. These dogs have a hyper-maturing of their intervertebral disc (IVD) which causes the disc to dry out and not be able to absorb energy. As a result the disc is overloaded and it ruptures, unfortunately the path of least resistance is up into the spinal canal and since the canal is made of bone it is limited in the amount of space in the canal and the disc material ends up pushing on the spinal cord and “pinching” off the signals to and from the brain and the animal has neurological dysfunction. The changes can be subtle such as ataxia (drunk looking) to severe as not being able to walk or feel the back legs at all. When dogs can’t feel pain in the legs it is called deep pain negative and is a worse prognosis then if they can feel their legs or even move them a small amount.

When animals are severe enough and require surgery we start with a myelogram (see myelogram description) to be able to visualize the location of the ruptured disc material, once we have located the area then we proceed to surgery. During the surgery a small window of bone is removed from the spinal canal which allows us to remove the disc material. This in turn allows the spinal cord to not be pinched anymore and to start healing. There are two reasons the spinal cord stops sending information, one the physical pinching of the cord with the disc material and the second the concussive force (trauma) that was caused to the cord when the injury happened. Due to these two reasons many of these cases take time to recover from surgery and regain the ability to walk again, usually over weeks.

Overall the prognosis is good for these dogs if we catch them early enough. The ones that do not have deep pain sensation do not have as good of a prognosis, but many of them can still do very well.