IVDD - Intervertebral Disc Disease
A normal canine spine is comprised of many vertebrae that house and protect the spinal cord. In between almost all vertebrae is an intervertebral disc that acts as a stabilizer and shock absorber. The intervertebral disc has two primary components: an inner jelly-like nucleus pulposus, and an outer shell the annulus fibrosus. Intervertebral/degenerative disc disease is a severe neurologic condition affecting many dogs especially chondrodystrophic breeds. As the disc degenerates, the nucleus pulposus loses its pliability and becomes dehydrated. A dried-out disc has less ability to withstand forces and is more likely to leak out of its shell and herniate into the spinal canal. The extruded disc material can cause concussion to the spinal cord and can further compromise its function due to compression of the cord from the presence of disc material in the canal.
Dogs can be variably affected, but are generally placed into five grades of severity (all animals having spinal pain).
1. Spinal pain alone.
2. Walking but weak and wobbly.
3. Unable to walk or stand without assistance.
4. No voluntary motion of the limbs.
5. Loss of pain sensation in the limbs.
Symptoms can come on suddenly (from normal to unable to walk in the matter of hours) or more slowly over time (unresolving pain or slowly worsening weakness).
Making a diagnosis of intervertebral disc disease is done through advanced imaging. Ideal imaging of the spinal cord is via MRI. SAVE offers a 16-slice multidetector Toshiba CT scanner as an excellent alternative for many cases. CT can image the dog’s spine in seconds often under heavy sedation alone. Plain CT can accurately diagnose spinal cord compression in 80-90% of dogs and is especially sensitive in chondrodystrophic dogs due to their commonly mineralized discs. If necessary, a contrast dye can be injected around the spinal cord to enhance the sensitivity of the CT to >90%.
Approximately 50-60% of dogs with the ability to feel their toes will regain the ability to ambulate on their own with medical management. With surgical decompression, the prognosis rises to ~90%. If the animal loses the ability to feel their toes, however, only 5% of dogs will recover with medical management and only ~50% with surgery. Full recovery can take months to years with the majority of improvement in the first 6 weeks.
Surgical decompression can be performed at SAVE via ventral slot (cervical), hemilaminectomy (thoracolumbar), or dorsal laminectomy (lumbar) by our board-certified small animal surgeon Cory Pinel, DVM, DACVS-SA who has extensive experience with spinal imaging and surgery. Animals are typically hospitalized for several days for pain control and nursing care are administered by our 24-hr staff. Any severely affected dog should be considered an emergency and assessed ASAP.