Intervertebral Disc Disease (IVDD)
Intervertebral Disc Disease (IVDD) is a common occurrence in chondrodystrophoid dogs like Dachshunds, Beagles, Cocker Spaniels, Pekingese, etc (aka dogs with shorter angular limbs). Dogs with this body frame also have an abnormality of the discs that serve as shock absorbers between their spinal bones. The normal disc which should have a strong fibrous outer ring with a gel center. Instead, in these dogs, their discs can have a weak fibrous shell and a gritty calcified center. When their disc bulges or ruptures, pressure on the spinal cord can cause anything from pain to permanent paralysis.
When a disc slips or ruptures, the degree of dysfunction is rated to help determine the prognosis of the patient. This following scale outlines the progression of disease from mild to severe signs.
1. Back or neck pain only.
2. Wobbly gait (sometimes called the “Drunken Sailor”). Pet does not seem to know where
their legs are as they walk.
3. Paralysis of the limbs. Complete loss of ability to move legs.
4. Loss of ability to feel legs. No stimulus to pain.
When the pet ‘s neurological exam places them in any of the first 3 steps, the prognosis remains favorable. If the exam is consistent with step 4, the prognosis is guarded to grave. When a pet is presented with a ruptured disc in the back (most common location), a CT scan (and myelogram if necessary) is performed. These tests show the exact location of the disc to allow for precise planning of surgery.
The goal of surgery is to remove the offending disc material and return the spinal cord to its normal position. The procedure is called a hemilaminectomy, because the wall of the vertebra is the lamina and the surgical approach is to make a small window in only a portion of the wall.
Most patients are discharged within a few days of the procedure. An important point to remember is that everything behind the disc (towards the tail) is affected. This includes not only the rear limbs, but also the urinary bladder. Many dogs will need to have their bladder manually evacuated until voluntary control returns.