Introduction to Intervertebral Disc Disease (IVDD) in Dogs

Intervertebral Disc Disease (IVDD) is a prevalent cause of spinal cord issues in dogs. This condition manifests in different forms, commonly categorized as Type-1, Type-2, and sometimes Type-3 discs. Type-3 discs are akin to a condition known as Fibrocartilaginous Embolism (FCE).

Type 1 discs, often referred to as “ruptured discs,” and Type 2 discs, known as “slipped discs,” can occur in any breed. However, Type 1 discs are more commonly observed in small breed dogs, while Type 2 discs typically occur in larger breeds. Understanding these distinctions is helpful, but it's important to recognize that individual cases may not always follow these patterns, with some dogs experiencing multiple types of disc issues.

Type-1 IVDD

Type-1 IVDD arises from a combination of genetics and unfortunate circumstances. Breeding for certain physical traits, such as the short legs seen in Dachshunds, has inadvertently led to a predisposition for disc diseases. The genetic culprit often involved is the CDDY gene, for which testing is available to determine if your dog carries it.

So, what impact does the CDDY gene have? Imagine a healthy spinal disc as a jelly donut, with a tough outer layer called the annulus and a soft, gel-like center known as the nucleus pulposus, serving as a shock absorber. In dogs with the CDDY gene, this inner gel hardens, diminishing its shock-absorbing capabilities. When such a dog engages in activities like jumping off a couch, the outer annulus may tear, causing the now-hardened inner material to extrude. This extrusion can exert pressure on the spinal cord, leading to pain, incoordination, and weakness.

Type-2 IVDD

Type-2 IVDD is primarily attributed to the gradual wear and tear of the spinal discs over time. Normal activities and movements can cause small tears in the disc's tough outer rim, the annulus. These tears heal but may lead to an enlargement of the annulus, which can eventually exert pressure on the spinal cord and nerves.

The progression of Type-2 IVDD tends to be slow, resulting in a gradual onset of symptoms. You might notice changes in your dog's behavior, such as reluctance to climb stairs or jump into a car. They may also seem uneasy on hard surfaces like hardwood or tile floors and you may hear their nails scuffing against the pavement during walks. While the signs can be subtle at first, some dogs may experience a sudden worsening of symptoms after a prolonged period of minor indications. If you suspect your pet is exhibiting signs of spinal disease, it's important to schedule an appointment with your veterinarian to assess and address the issue.

Diagnosis

To accurately diagnose IVDD in dogs, imaging studies of the spine are required. The diagnostic process typically begins with X-rays, which offer a relatively cost-effective method for visualizing the spine. X-rays primarily serve to rule out more severe conditions, such as bone infections or tumors. While they can provide indications of whether a dog might have Type 1 or Type 2 IVDD, X-rays alone do not offer a definitive diagnosis.

Consequently, the next step is often an MRI (Magnetic Resonance Imaging). An MRI can definitively diagnose IVDD in all affected dogs and about 90% of other spinal diseases. Despite being a more extensive test, its importance in accurately diagnosing IVDD and other spinal issues cannot be overstated.

Treatment and Prognosis for IVDD in the middle and lower back

Intervertebral Disc Disease (IVDD) in the mid to lower back, as opposed to the neck, requires a different approach. Let’s explore the treatment options for mid to lower back IVDD, which is more common.

There are two primary treatment methods for IVDD: conservative management and surgery.

Conservative Management: This approach is often considered, particularly for dogs that can still walk, even if their movement is uncoordinated or weak. Dogs with walking ability have about a 70% chance of pain improvement and regained walking ability with rest and time. However, there is a long-term risk of recurrence, with up to a 50% chance of experiencing similar issues again. Read in more detail here.
Surgical Intervention: Surgery is recommended when a dog cannot walk, is in severe pain, or does not respond to conservative management. Though it's a major procedure, surgery is highly effective, aiding about 95% of dogs in regaining their ability to walk, provided they don’t have the most severe form of spinal injury. Surgery also helps in reducing the likelihood of recurrence, with only about 10% of dogs experiencing another problematic IVDD episode in the future.

Severity of Symptoms

For assessing the severity of symptoms in dogs with Intervertebral Disc Disease (IVDD), a five-point grading system is used. It’s important to have your veterinary team evaluate your dog to accurately determine their condition on this scale:

Painful but Coordinated: The dog experiences pain but does not have issues with incoordination or strength.
Incoordination and Potential Strength Issues: The dog shows signs of incoordination and possibly weakened strength but can still walk unassisted.
Limited Mobility: The dog can still move its legs but cannot walk without assistance.
Paralysis with Pain Sensation: The dog cannot move its legs but can still feel pain in them.
Complete Paralysis and Loss of Pain Sensation: The dog cannot move its legs and has lost the ability to feel pain in them.
**Don’t try this at home. Many people are tempted to try to grade their pet’s symptoms themselves. There are some subtleties here that make that challenging. In 15 years, we’ve seen people get it wrong more often than not. Let us help!

Treatment and Prognosis for IVDD in the neck

Intervertebral Disc Disease (IVDD) in the neck region presents unique challenges. Resting a neck injury is considerably more difficult compared to other spinal areas since dogs can still move their heads significantly, even when confined to a crate. Approximately 50% of dogs with even mild neck issues do not respond well to conservative management.

Moreover, neck issues can be more hazardous than mid to lower back problems due to the presence of crucial nerves in the neck, including those controlling breathing. In severe cases, these nerve impairments can lead to respiratory difficulties, and dogs with substantial symptoms might risk stopping breathing.

Surgery is strongly advised for dogs struggling with walking due to neck IVDD. The success rate of surgical intervention in these cases is about 90%, except in instances of severe symptoms.

Treatment and Prognosis for dogs with severe IVDD

In cases of severe Intervertebral Disc Disease (IVDD), where the injury to the spine is so extensive that dogs lose sensation in their feet (often referred to as "loss of deep pain"), the prognosis becomes more uncertain. The ideal course is to avoid reaching this stage and opt for surgical intervention while the dog can still feel its feet. However, this is not always possible.

For dogs that have lost foot sensation, the likelihood of recovery with surgery ranges between 50 and 70%. An MRI can reveal spinal cord damage, which might affect these odds. Without surgery, the chance of recovery drops to about 10-20%. This presents a difficult decision for pet owners, weighing the risks and potential outcomes of major surgery against the uncertain prognosis. It's important to consider whether you, as a pet owner, are prepared for the possibility of unsuccessful surgery. Dogs that do not regain the ability to walk may still have happy lives with the aid of a wheelchair, but caring for a disabled pet is a significant commitment and may not be feasible for every family.

Another concern in severe cases is the risk of progressive myelomalacia, affecting approximately 10% of dogs with advanced IVDD. This condition involves the gradual deterioration of the spinal cord, leading to pain and eventual respiratory failure as it progresses to the neck. In such cases, euthanasia is often the only humane option, as the condition is both painful and irreversible, even in dogs that have undergone surgery.

How quickly do we need to go to surgery?

The urgency of surgical intervention for Intervertebral Disc Disease (IVDD) has been a topic of significant debate among neurologists and surgeons over the past decade. While some specialists previously insisted on immediate surgery, even during late-night hours, current consensus, supported by extensive research, suggests that surgery should be performed as soon as practically possible, ideally within a few days.

Delaying surgery for weeks or months could potentially impact the effectiveness of treatment in alleviating your dog’s symptoms. The extent of neurological injury depends on both the severity and duration of the injury. Even mild injuries, if left untreated for an extended period, can cause lasting damage to the spine. While injured nerve cells can often recover, once a nerve cell dies, it cannot be regenerated. The canine spine has a remarkable capacity for adaptation and reorganization, but this ability has its limits. Therefore, timely surgical intervention is key to maximizing the chances of recovery and minimizing long-term impacts.

When is this an emergency?

It's crucial to seek emergency veterinary care if your pet exhibits any of the following symptoms:

A sudden loss of the ability to walk.
Failure to urinate for more than 24 hours.
Experiencing pain that is not alleviated by prescribed medications.

Intervertebral Disc Disease in dogs