&geometry(309x90) "VSOS")
Intervertebral Disc Disease (IVDD)
Understanding IVDD
Intervertebral Disc Disease (IVDD) is a condition that affects the discs that sit between the bones of the spine (vertebrae). These discs act like cushions, absorbing shock and allowing the spine to move comfortably.
Each disc has a tough outer layer and a soft, jelly-like centre. Over time, these discs can weaken or degenerate leading to rupture or bulge out (herniate of the intervertebral disc and press on the spinal cord, much like a “slipped disc” in people, causing pain, incoordination, weakness, or even paralysis or Loss of bladder or bowel control.
IVDD can occur in any breed, but it’s most common in dogs with short legs (Chondrodystrophic dogs), such as Dachshunds, French Bulldogs, Cocker spaniels and Shih Tzus.
Common Symptoms
The symptoms of IVDD can appear suddenly or develop slowly, depending on which type of disc herniation it is and/or how severe the disc problem is and where it occurs along the spine.
Signs to watch for include:
- Reluctance to move, jump, or climb stairs
- Crying out or showing signs of pain when touched or picked up
- Change in posture (such as stiffness on the neck or a hunched back)
- Wobbliness when walking.
- Dragging the legs or difficulty walking
- Paralysis of the legs.
- Loss of bladder or bowel control in severe cases
If your dog shows sudden weakness or paralysis, this could indicate a medical emergency, and you should contact our team immediately.
What Causes IVDD?
In most dogs, IVDD develops as part of a degenerative process - meaning the discs gradually lose their strength and flexibility over time, and in at risk breeds they have a genetic change that can make them to develop early the wear and tear of their spinal discs.
A simple movement, such as jumping off furniture or even getting up from bed, can cause the weakened disc to rupture.
Although trauma can contribute in some cases (especially in larger breeds), most affected dogs already have underlying disc degeneration before the event occurs.
The Grades of IVDD
Veterinary specialists classify IVDD into five grades based on severity:
| Grade | Description | Mobility / Pain |
|---|---|---|
| Grade 1 | Back pain only | The dog walks normally but is painful on their back. |
| Grade 2 | Mild to moderate weakness and/or wobbliness in their back legs | Still able to walk, but coordination is affected |
| Grade 3 | Severe weakness and/or wobbliness in their back legs that make them unable to walk. | Cannot walk without support; still has some movement |
| Grade 4 | Paralysis (no movement) with preserved deep pain sensation on the back legs. | No movement in the hind limbs but still feels deep pain. |
| Grade 5 | Paralysis with loss of deep pain sensation. | No movement or sensation on the pelvic limbs. |
What is the prognosis for Dogs with Intervertebral Disc Disease (IVDD)
For dogs showing only mild back pain or very slight weakness, medical management, such as rest, medication and careful monitoring, often leads to a fair to good recovery. However, there remains a possibility that symptoms could return or worsen in the future.
When surgery is required, the chances of recovery are closely linked to whether the dog can still feel deep pain in its paws or limbs before the procedure. If sensation is still present (Grade 1 to 4), the outlook for regaining mobility is generally positive.
If a dog has completely lost the ability to feel deep pain before surgery (Grade 5), the likelihood of full recovery is unfortunately much lower.
In some severe cases of IVDD, dogs may develop a condition called myelomalacia, in which the spinal cord tissue begins to soften and degenerate progressively. This is a progressive and often fatal complication that occurs most often in dogs without deep pain sensation, though it can rarely affect those with milder symptoms as well.
Even if a dog does not regain the ability to walk, many can still enjoy a good quality of life with the help of a specially designed dog wheelchair or mobility aid.
Types of IVDD
There are three main types of IVDD. Understanding the differences helps explain why symptoms and treatment can vary between dogs.
Intervertebral disc Extrusion or Hansen type I IVDD
- Description: A sudden rupture (extrusion) of the inner disc material of the intervertebral disc to the vertebral canal pressing directly on the spinal cord or nerves.
- Common in: Chondrodystrophic breeds such as Dachshunds, Cocker Spaniels, and Shih Tzus. However, can also occur in larger breeds.
Intervertebral disc Protrusion or Hansen type II disc disease IVDD
- Description: A slower, more gradual bulging (protrusion) of the outer layer (anulus fibrosus) that causes ongoing pressure on the spinal cord over time.
- Common in: Larger breeds such as German Shepherds and American Staffordshire terrier.
Acute Non-Compressive Nucleus Pulposus Extrusion or Type III IVDD.
- Description: A sudden herniation of a small fragment of disc material into the spinal canal leading to a contusion of the spinal cord without major compression, often during intense exercise.
- Common in: Any breed, though there is a trend to be more common in medium/large dog.
How IVDD Is Diagnosed
A full neurological examination helps determine which area of the spine is affected.
While X-rays can show the outline of the spine, they cannot show the spinal cord or the discs clearly.
For that reason, MRI (Magnetic Resonance Imaging) is considered the gold standard for diagnosing IVDD because it shows both the spinal cord and surrounding soft tissues in great detail. It helps us determine not only where the disc problem is, but also how severely the spinal cord is affected, which can guide prognosis and treatment choices.
Because dogs must remain perfectly still during the scan, MRI is performed under general anaesthesia for safety and accuracy.
While CT scans and CT or Xray myelographies can be helpful in certain cases, they cannot match MRI’s accuracy or its ability to assess spinal cord health. Choosing MRI means the best chance for an accurate diagnosis, tailored treatment, and a faster path to recovery for your dog. Also, myelography carry a slightly higher risk of side effects such as seizures.
When Is Surgery Needed?
Not every dog with IVDD requires surgery.
- Mild cases (Grades 1-2): Often managed through conservative management with rest, pain relief, and anti-inflammatory medication.
- Moderate to severe cases (Grades 3-5): Surgery is usually recommended to relieve the pressure on the spinal cord.
Dr Diego Alza, our neurology specialist, explains that surgery is advised when:
- The dog can no longer walk or is about to lose that ability
- The signs are progressing quickly
- MRI shows significant spinal cord compression in addition to the clinical signs.
At VSOS, spinal surgeries are carried out with a high-powered operating microscope. This advanced technology gives our neurosurgeons a magnified, detailed view of delicate structures - the same standard of precision used in human neurosurgery.
What Does the IVDD Surgery Involve?
The surgery logic is to decompress the spinal cord (decompressive surgery), this involves removing the disc material that is compressing the spinal cord.
Different techniques are used depending on the area of the spine:
- Mini-Hemilaminectomy or hemilaminectomy: performed more commonly on the middle and lower spine. The disc is accessed from the side to relieve pressure.
- Ventral slot: For discs in the neck (when the disc is locate under the spinal cord), a small window is made through the underside of intervertebral disc and the vertebrae.
- Dorsal laminectomy: For lower back (lumbosacral) cases, the “roof” of the spinal canal is removed to visualise and decompress the nerves.
These surgeries require specialised equipment and expert training.
At VSOS, all procedures are performed by our experienced neurology and surgical team using advanced imaging and surgical guidance tools.
What to Expect After Your Dog’s Surgery
After the operation, your dog will be allowed to wake up calmly and comfortably from the anaesthetic in a quiet recovery area. Our team will provide effective pain relief and supportive care to keep your pet relaxed and stable. During this time, your dog is closely monitored by our experienced veterinarians and nursing staff.
Once fully awake and settled, your dog will continue to rest overnight. The following morning, they’ll be moved to our surgical ward, where our dedicated nurses and support team will provide ongoing care, comfort, and monitoring to ensure a smooth and safe recovery.
When Can My Dog Go Home After Spinal Surgery?
The length of your dog’s hospital stay after spinal surgery depends on their individual recovery, including comfort level, ability to move, and ability to urinate on their own. In most cases, dogs remain in hospital until they no longer need injectable pain relief and are comfortable taking oral medications only. Our team will ensure your dog is safe, comfortable and ready before going home.
When to Seek Help
You should seek specialist attention if your dog:
- Shows signs of back or neck pain
- Becomes unsteady or weak in the hind limbs
- Suddenly cannot walk or move normally
- Stops urinating on their own or loses bladder control
Early assessment and treatment offer potentially better chance of recovery. If you begin to notice any symptoms in your dog, it’s best to visit your local veterinary clinic as soon as possible.
At VSOS, we provide 24/7 emergency care, advanced imaging and on-call surgery when needed.
Why Choose VSOS for Your Pet’s Spinal Care
At VSOS (Veterinary Specialists of Sydney), our Neurology and Neurosurgery team, led by Dr Diego Alza, performs spinal surgeries for IVDD multiple times each week, making this one of the most refined and experienced services in our hospital.
Dr Alza is truly passionate about neurosurgery - it’s his favourite part of veterinary medicine. He takes great pride in helping dogs walk again and enjoy a happy, active life. With exceptional specialist training and extensive surgical experience, he continues to stay at the cutting edge of surgical innovation and modern techniques.
We combine state-of-the-art imaging (MRI and CT) together with the precision of a high-powered operating microscope, the same standard used in human neurosurgery. Our dedicated nursing and rehabilitation teams provide expert, compassionate care, supporting every patient from diagnosis through recovery.
At VSOS, our specialists take the time to discuss all treatment options, both medical and surgical, so you can make informed decisions in your dog’s best interest. Surgery is only recommended when it truly benefits your dog’s health. Our goal is to help pets regain mobility and quality of life with skill, innovation, and heart.
