Overview

The vertebral column is made up with individual verterbrae, which are cushioned by intervertebral discs that allow an animal to flex its back. These discs are soft and gelatinous on the inside in order to absorb the forces exerted on the vertebral column when the animal is moving. When a microscopic piece of this gelatinous material dislodges, it can enter and form a blockage in the arteries that feed into the spinal column, thus creating a fibrocartilaginous embolism (FCE). With no blood supply, the section of spinal cord affected by the embolism dies, and the dog becomes paralyzed in one or multiple limbs.

FCE typically occur in young adults around 3 to 6 years of age, and about half of the dogs affected are large and giant breeds. In many cases the paralyzing effect occurs after minor injuries such as a fall, or simply a bad landing after a jump; however, the injury itself is usually not painful, and the paralysis is the only apparent symptom. The location and severity of the embolism will determine the degree of paralysis; some dogs may just be weak in the affected limb, while others become completely paralyzed.

It is not yet understood why or how FCE occurs, and the exact cause of this condition remains unclear.

Symptoms and Diagnosis

At the onset of the embolism, there might be a painful yelp when the dog collapses or suddenly becomes weak in one or multiple limbs. However the pain is not persistent, and no other signs of trauma can be detected except for the paralysis. In milder cases the dog might maintain some degrees of motor function, but slip and fall more than usual.

Diagnosing FCE is usually a process of elimination since the blocked artery will not show up in X-ray. One distinguishing feature of FCE is the lack of pain, since there are usually considerable amounts of pain involved if the paralysis is caused by acute trauma or disc herniation. Magnetic Resonance Imaging (MRI) can be used to positively identify an embolism, however most veterinarians do not have access to this expensive method. Currently the only way to be absolutely sure of FCE is a post-mortem autopsy. For the purpose of treatment and rehabilitation, the safe practice is to assume FCE when other possibilities have been excluded.

Treatment

The damage to the spinal cord is permanent, and therefore effectiveness of treatment is limited. However, dogs that receive treatment within the first 24 hours of the injury might have a better prognosis. While the effect of the paralysis cannot be reversed, it does not worsen over time, and many dogs will ultimately regain some level of motor function and lead an otherwise normal life. Relief techniques such as water therapy and massages will prevent muscle atrophy and help the animal to better function with limited mobility.