Intervertebral discs are the cushions between the bony bodies of the vertebrae; they absorb shock. These discs have a fibrous outer ring, and a soft, gelatinous inside; they are like a jelly-filled doughnut.
There are two major types/causes of Intervertebral Disc Disease (IVDD) – traumatic, and degenerative. Trauma can cause rupture of the intervertebral discs, leading to an explosion of disc material (or jelly filling) into the vertebral canal, which can bruise the spinal cord. Even though there is ‘disc material’ in the vertebral column, there is truly nothing putting pressure on the spinal cord (i.e. there is nothing to surgically remove). Traumatic intervertebral disc disease will typically heal on its own, without surgery, however it can take weeks to months to regain normal neurologic function. Medical management of these patients requires strict kennel rest along with aggressive pain management. Normal neurologic function may not be a complete recovery, sometimes neurological deficits may still be present even after full healing, depending on the severity of the initial injury.
Degenerative intervertebral disc disease is when the intervertebral disc degenerates, usually because of genetics, and the disc ruptures, leading to large chunks of degenerative disc (chunks of doughnut, if you will) pushing on the spinal cord, causing compression. Degenerative disc disease requires surgery to remove the chunks of disc that are putting pressure on the spinal cord. Chondrodystrophic breeds are predisposed to this disease, but any breed can be affected.
If the ruptured disc is in the thoracolumbar region, one of the most common surgeries performed is a hemilaminectomy. This surgery removes a portion of the top part of the vertebral canal over the ruptured disc. This alone relieves pressure and gives the spinal cord more space. It also allows the surgeon access to remove the chunks of disc material. Depending on many factors, the surgeon may also choose to ‘fenestrate’ nearby discs to relieve pressure, decreasing the likelihood of them rupturing in the future.
Surgery causes inflammation, and owners must be prepared for the patient to be slightly neurologically worse after surgery. Recovery from surgery (and with medical treatment) can be a long road however surgery also decreases the chance of recurrence. Recovery from surgery can take weeks to months, as it can with medical therapy. Postoperative activities should be significantly restricted for 4-8 weeks.