Owner Fact Files: Intervertebral Disc Disease
Part 5 in the Owner Fact Files series, discussing Intervertebral Disc Disease (IVDD), a condition affecting the spine, which is the most common spinal disease seen in dogs, and sometimes cats.
It is likened to a slipped disc in humans, and surgery for IVDD is the most frequently performed spinal surgery. Read on to find out more about why it happens and how it is treated.
What is an Intervertebral Disc?
The spinal cord is an extremely important and fragile organ in the body, so in order to protect it, it sits within a bony canal running through the vertebrae bones. Intervertebral discs are found between each junction of the vertebrae. They are positioned along the length of the spine, and act as a rubber like cushion, preventing contact of the bones.
The vertebrae and the intervertebral discs together, function to allow the back to move - flexion, extension and lateral flexion (up, down, and sideways movement). The discs support the spine and also act as shock absorbers.
The normal structure of a healthy intervertebral disc is a harder outer layer, called the annulus fibrosus, and a soft gel like middle, called the nucleus pulposus. The structure is often likened to a jam doughnut - nucleus pulposus = jam, annulus fibrosus = doughnut, and this is a useful way to visualise the disease process.
What is Intervertebral Disc Disease?
IVDD is generally a degenerative condition which involves the structure of the discs changing over time. These changes in structure cause an impingement on the spinal cord, which ultimately leads to the presentation of symptoms.
Unfortunately, some dogs are genetically more at risk and can suffer with disc problems at a young age. Breeds that have disproportionately short and curved limbs, plus long backs, are more at risk e.g. Dachshunds, Bassett Hounds, Bulldogs.
Other factors that are linked to IVDD include body weight and condition, as excess weight places additional strain on the spine, particularly during movement. In degenerative cases, age is a factor, as the structure of the discs changes over time. In other cases in which a dog is more prone, lifestyle and exercise can be linked to IVDD. For example, allowing an at risk dog to jump on/off furniture, puts stress on the spine which can be avoided. Finally, in some research it has been suggested that dogs that have been neutered are more likely to have disc problems.
What's happening inside the spinal column? (the science bit)
There are 2 main types of IVDD, which are characterised by different structural changes happening in the discs.
Type 1 occurs when the disc begins to degenerate, and the soft centre (nucleus pulposus) loses waters and becomes dehydrated. Once the disc is dehydrated, it no longer works as an effective shock absorber, and the soft gel calcifies or hardens. This change ultimately leads to disc herniation or rupture. Thinking back to the doughnut analogy, the nucleus pulposus or jam, explodes out, tearing the annulus fibrosus or doughnut. The rupture normally occurs in an upward direction, compressing the spinal cord.
In Type 2 cases, the annulus fibrosus, or doughnut, bulges and protrudes, also putting pressure on the spinal cord. Sometimes the outer layer will tear and the loose fragment compresses the cord as well. This type occurs more slowly, because the disc progressively protrudes, with worsening signs.
Type 1 is generally seen in smaller breeds, with the characteristic short legs and long back conformation. The disease is seen in dogs aged 2 and over, and the onset of signs is usually sudden. In contrast, Type 2 is more often seen in medium to large breeds, with any body type, mostly between the age of 5 - 7. The onset of signs can also be sudden, but the initial progression is slower.
As previously stated, the spinal cord is a vital organ, which helps to carry signals all around the body to allow us to function. In cases of IVDD, when it becomes compressed, the transmission of information is slowed or stopped completely, and this is what causes the symptoms we see.
The signs that you may notice are:
- Pain localised to the back or neck (most common)
- Abnormal posture - back hunched, head held low
- Shivering and panting
- Unwilling to move - possible limp when moving
- Difficulty jumping and going up/down stairs
- Poor control of the hind limbs, ranging to complete paralysis
- Paralysed bladder - cannot urinate (severe cases)
- Loss of pain sensations (severe cases)
If you see any of these symptoms in your dog and you have concerns, please speak to your vet immediately.
The treatment selected depends on the severity of the damage to the spinal cord.
IVDD can be managed conservatively in milder cases with drugs to reduce swelling and pain. Rest will be advised to prevent further damage. Physiotherapy is used to relieve pain, restore strength, and improve coordination.
When the damage is more severe, and the dog is paralysed or incontinent, the prognosis is better with surgery. Surgery involves a window being made to expose the spinal cord so the disc material can be removed. This removes the pressure from the cord. These techniques are known as fenestration and decompression.
How can physiotherapy help?
The rehabilitation process is really important in cases of IVDD, and physiotherapy would be recommended with both conservative and surgical management. In the initial stages, physio will focus on reducing pain and inflammation at the site of injury and postoperatively. Crate rest will be advised for the initial period to prevent further injury, so passive range of motion exercises help to keep the joints mobile and healthy.
As your dog progresses, the exercises will be advanced to get your dog standing, supporting their own weight, and walking over time. The therapeutic exercises prescribed will help to build muscle, improve balance and coordination, and re-educate gait. Additional electrotherapies may be used to manage pain, encourage healing, and stimulate muscle contractions in weak areas.
For more information on how physiotherapy could benefit a case of Intervertebral Disc Disease, please get in touch - firstname.lastname@example.org // 07795163445.
Prognosis varies, but generally dogs will regain the use of their limbs in several weeks. For some dogs the process is slower, and unfortunately in the minority of cases, function will never return. Appropriate aftercare and therapy is key to rehabilitate IVDD cases.
That brings me to the end of this blog, if you have any questions please do get in touch. Make sure you come back next month to read the next Owner Fact File, and give me some feedback if you like these posts.
If there is anything I can do to help your animals, please drop me a message - Nancy
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