Intervertebral disc disease (IVDD), a condition that commonly affects dogs, but rarely cats, can cause significant pain, and possibly lead to permanent paralysis if left untreated. Our team at Animal Internal Medicine and Specialty Services (AIMSS) wants to provide information about this problematic disease.
What is intervertebral disc disease in pets?
Your pet’s spine is composed of several small bones called vertebrae that protect the fragile spinal cord. These vertebrae allow your pet’s back to be flexible, and are separated by intervertebral discs, which act as a cushion between the vertebral bones. The discs have a fibrous outer shell (i.e., the annulus fibrosus), and a jelly-like interior (i.e., the nucleus pulposus). IVDD occurs when part of the intervertebral disc presses on the spinal cord, nerve roots, or the dorsal longitudinal ligament that runs above your pet’s vertebral column. Two IVDD types can affect pets.
- Type I IVDD — This type is more common in chondrodysplastic breeds, such as dachshunds, corgis, basset hounds, and beagles, and occurs when the disc’s jelly-like inner nucleus becomes mineralized, extrudes through the fibrous outer layer, and puts pressure on the spinal cord or nerves that exit the spinal cord.
- Type II IVDD — This type is a slower degeneration process, and occurs when the fibrous outer layer breaks down, allowing the inner and outer disc components to compress the spinal cord. This type is typically seen in dogs such as German shepherds and Labrador retrievers.
What are intervertebral disc disease signs in pets?
IVDD is a veterinary emergency, and should be addressed as soon as possible. Clinical presentation depends on the vertebral section affected, but once nerve damage develops, progression follows a predictable pattern.
- Pain — Your pet will experience back or neck pain, which they may express by vocalizing when handled, refusing to move, or being unable to turn their head.
- Incoordination — Your pet may walk abnormally because of mild pressure on the spinal cord, and their hind limbs may cross as they step forward.
- Motor function loss — Your pet may lose the use of their hind limbs, and also lose bladder control, because of extreme pressure on their spinal cord.
- Pain perception loss — If the pressure on the spinal cord is not alleviated, your pet can lose pain perception, which signals severe cord injury.
How is intervertebral disc disease diagnosed in pets?
When a pet presents for back pain and spinal weakness, distinguishing between spinal cord compression and other conditions is important, because surgery can benefit some compressive issues, but not many other conditions. Diagnostic approaches include:
- Neurological exam — A thorough neurological examination is performed to test your pet’s reflexes, and determine where the spinal cord is affected.
- X-rays — Plain X-rays can show a dislocated or fractured vertebrae, but since the spinal cord cannot be seen on plain X-rays, other imaging techniques may be necessary to locate the injured area.
- Myelogram — Your pet will need general anesthesia to undergo this technique, which involves injecting a dye around the spinal cord. This allows the spinal cord to be visualized on X-ray, and the dye narrows where the spinal cord is compressed, identifying the affected area.
- Computed tomography (CT) — Our hospital also offers the option for advanced imaging, such as a CT scan, which, combined with X-ray images taken from different angles around your pet’s body, provides a more detailed image than plain X-rays.
- Magnetic resonance imaging (MRI) — We also can perform an MRI, which involves using a strong magnetic field and radio waves to create a detailed image of your pet’s vertebral column.
How is intervertebral disc disease treated in pets?
Depending on the severity of your pet’s condition, treatment can involve conservative management or surgical intervention.
- Conservative treatment — Most important in conservative management is strict confinement. Typically, your pet will need to cage rest for three to four weeks, followed by another two to three weeks while they gradually resume normal activity. Your pet will need to be carried, or walked on a leash, to relieve themselves, and then returned immediately to the cage. In addition to confinement, medications to control pain and inflammation, including steroids, non-steroidal anti-inflammatories, and muscle relaxants, are used. After the initial confinement period, physical therapy is often instigated to improve your pet’s comfort, and return them to normal function.
- Surgical treatment — Surgery may be required if your pet’s condition is severe. Once the compressed area is localized, the spinal cord will be accessed to remove the disc material. Surgical approaches include:
- Ventral slot — This procedure is used when cervical discs are affected, and the spinal cord is accessed from the underside of the neck.
- Hemilaminectomy — The most common approach for herniations in the thoracolumbar region, this involves accessing the spinal cord through a small window in the side.
- Dorsal laminectomy — This is the most common approach for herniations in the lumbosacral region, and involves accessing the spinal cord from the top.
Pets affected by IVDD have a better prognosis if they receive veterinary care as soon as possible after they develop signs. If your pet is exhibiting IVDD signs, immediately contact our team at Animal Internal Medicine and Specialty Services, so we can get them walking again.