Invertebral disk disease (IVDD)

The normal canine/feline spinal cord is protected by blocks of bone known as vertebrae. Between each vertebra sits the intervertebral disk. This disk is composed of a fibrous outer coating and a gelatinous centre, and it helps to provide structural support to the spine. Over time the disk can degenerate, ultimately leading to intervertebral disk disease (IVDD). There are two main types of IVDD and both the back and neck can be affected. 

Type I IVDD

This occurs when the gelatinous centre of the disk becomes mineralized and extrudes/herniates out of place, causing compression of the spinal cord. Clinical signs can range anywhere from back pain to complete paralysis and loss of feeling. Dachshunds and other small breed dogs are at increased risk of developing this problem. 

Type II IVDD

This occurs when the outer fibrous layer of the disk becomes thickened and causes spinal cord compression. Clinical signs tend to be slower to develop than in dogs with Type I IVDD. Large breed and older dogs are at increased risk of developing this problem. 

Diagnosis

X-rays can be very helpful in determining the presence of mineralized intervertebral disks, assessing bone structure, etc., but in order to diagnosis IVDD advanced imaging such as MRI or CT is required. These tests allow visualization of the disks and spinal cord, which are soft tissues, and enables us to accurately determine which segment of the spinal cord is affected. 

Treatment

IVDD can be managed conservatively or with surgery. The type of treatment depends on the severity of clinical signs and results of diagnostic tests. 

Conservative management involves strict cage rest for 4-6 weeks +/- pain medications. Strict cage rest means confining a pet to small crate at all times, aside from brief bathroom breaks. Running, jumping, climbing and playing must not be permitted.  

Surgical management typically involves a procedure known as a “hemilaminectomy” for the back and a “ventral slot” for the neck. A special drill is used to remove a small window of bone from the vertebrae, allowing for visualization of the spinal cord and removal of as much extruded disk as possible. Patients usually remain in hospital for several days after surgery, receiving intravenous fluids, pain medications and bladder management. Recovery continues with strict cage rest at home. A recheck examination is performed 4-6 weeks after surgery.