Big “Bruiser” was a lovable, friendly four-year-old Bullmastiff. He was always forgetting his sheer size and was constantly crashing into things. He was so happy when he was able to run around free in an open field. After one day of exuberant exercise with a young Collie friend, his owner had noted a sharp yelp, then worryingly, “Bruiser” had been unable to stand on one of his back legs since. He was hopping on one back leg and struggling due to his sheer size.
He was brought into the surgery immediately and given a neurological examination and X-rays. His X-rays were all normal and further investigations indicated that he had had a suspected acute Fibrocartilaginous embolism. It was important to rule out any other cause of his acute symptoms, so an emergency referral for more advanced MRI imaging at one of the Veterinary Hospital Neurology referral units was advised. His MRI scan confirmed our suspicions.
Fibrocartilaginous Embolism is a sudden onset spinal cord injury because of a sudden blockage of a vessels blood supply to an area of the spinal cord. This is a disorder in which a piece of fibrous cartilage obstructs the blood supply to the spinal cord. It is suspected that fibrocartilage from the soft gel like centre (the nucleus pulposus) of an intervertebral disc enters a vertebral blood vessel, blocks the vessel, and this blockage causes damage to the spinal cord. When the flow of blood is reduced or stopped, that part of the spinal cord goes without oxygen and nutrients and the neurons in the spinal cord become dysfunctional and can die off, leading to the clinical signs we see.
A fibrocartilaginous embolism typically occurs during times of exertion and activity, such as running or jumping. Most dogs will yelp once, or seem painful for a short time, but later there is typically no pain associated with this disease. The usual signs are a very abrupt loss of function to one limb, both hind limbs, one side of the body or all four limbs, depending on what part of the spinal cord has been affected. Young to middle-aged large and giant breed dogs are often affected, affecting young adults between 3 and 5 years old, however dogs of any breed or age can be affected. It appears that FCE may more commonly occur in males than females.
A presumptive diagnosis is made based on the history and a thorough neurological examination. With an acute onset of neurologic weakness and absence of pain, a fibrocartilaginous embolism is the most probable diagnosis. Spinal radiographs are helpful to rule out a fracture or other traumatic cause, however in FCE cases X-rays are usually normal. More advanced diagnostic imaging is required to confirm the diagnosis. The best way to definitively diagnose an FCE is to perform an MRI (magnetic resonance imaging) of the part of the spinal cord affected. This will help to confirm a diagnosis and rule out other causes of acute neurologic weakness. An MRI can also help give a prognosis for the return of function based on the size of the area of damage. A CT scan (computed tomography) and myelogram are other tests that can be performed to look for other causes of spinal cord dysfunction but are less sensitive for confirming an FCE. With any loss of function due to a nervous system abnormality, a referral to a neurologist is always advised.
There is no direct therapy for an FCE as we do not have a way to remove the fibrocartilage from the blood vessels in the spinal cord. We can only rely on time to allow the spinal cord to make new blood vessels to the affected area. Often other blood vessels open to facilitate the collateral circulation to the spinal cord and the swelling surrounding the damaged area slowly resolves.
The immediate aftercare depends on how severely affected the patient is. Animals are typically hospitalised until they show signs of improvement as well as a return to voluntarily urination function. Some need hospitalised for critical care if they cannot stand or move their limbs, keeping them rested on a soft, well-padded bed, rotating them regularly to prevent bed sores. And an indwelling urinary catheter may have to be placed to help manage the bladder.
To improve strength and coordination physiotherapy and supportive therapy are the most important considerations in rehabilitation, as inactivity and recumbency results in decreased joint movement, stiffness and muscle weakness and contracture which all hinder a smooth road to recovery.
The prognosis for recovery from a fibrocartilaginous embolism is based on the severity and on the extent of the spinal cord injury. The long-term prognosis for returning to walking is good in most FCE cases. The rate and extent of recovery is variable and difficult to predict but can take days, to weeks or months. Most dogs tend to show a slow but steady improvement in the ability to walk over the first 2-6 weeks, whereas a full recovery may take much longer. Not every dog will improve though, and that is partly due to the severity of the initial injury.
Thankfully, the chances of having a second FCE in the future are slim. “Bruiser” made a slow, gradual but steady recovery, helped with regular physiotherapy sessions and with lots of support from his owners, who were so thankful and pleased to see him slowly come back to normal.