Visiting Veterinarian: Spinal cord injuries

Franny’s owner was backing out of her driveway on Memorial Day when she felt a bump. Not a big bump, but a bump. Jumping out to investigate, she discovered to her dismay that she had run into her own dog. She hadn’t been driving fast, and Franny, a sturdy seven-year-old Labrador retriever, did not appear seriously hurt, but, noticing a slight limp, this conscientious owner took Franny right in to the veterinarian covering emergencies for that holiday Monday.

The doctor found no major abnormalities and suggested taking radiographs, but Franny was looking so normal they agreed she could go home with pain medication and careful observation. The owner did just that — observe her — carefully. And what she observed wasn’t good. By early evening Franny was having difficulty walking. Her hind end was weak and she sat in an odd position, her rear legs sticking straight forward. The veterinarian on-call rechecked Franny. Concerned about possible spinal cord injury with this worrisome progression in symptoms, after a few quick tests to rule out immediately life-threatening internal injuries, they advised transferring her off-Island ASAP to see a neurologist and probably have an MRI.

Acute spinal cord injuries are common in veterinary medicine, often the result of trauma, like being hit by a car, or from age and breed-related intervertebral disc disease. Symptoms depend on location and severity of injury and include back pain and varying degrees of loss of feeling and/or function of the limbs. When presented with such a case, one of the first things veterinarians do is check deep pain perception. That sounds fancy but it just means we pinch Franny’s toes and see if she can feel it. Sometimes you have to pinch pretty hard, but as long as Franny has feeling we know the pathway running from her toes to her brain is intact. It’s not enough if her foot simply pulls away. Local reflexes can cause that. We want Franny to turn and look at the offending pinching hand, or to cry, or whine, or flinch. Anything to indicate that Franny’s brain has registered the sensation.

Dogs with deep pain perception have a much better prognosis than those without. Another parameter we assess is proprioception. Sounds fancy again, but it just means — does Franny know where her feet are? We take a foot and flip it over so the animal is resting on the top of the foot instead of the bottom. A dog with good proprioception will immediately flip the foot back to normal position.

When Franny arrived at Tufts University Foster Hospital for Small Animals, her mood was good, but she was unable to walk and had no proprioception in her hind legs. The neurologist thought the problem was somewhere between her third thoracic and third lumbar vertebrae. MRI confirmed that there was compression of her spinal cord on the left side between the ninth and tenth thoracic vertebrae as well as an injured disc in the lumbar area. Intervertebral discs are basically little cartilage shock absorbers that sit between the bones of the back. The bump from the car had apparently been just enough to cause what people sometimes call a “slipped disc.” Two, in fact. These put pressure on the spinal cord. Subsequent bruising and swelling interfere with transmission of nerve impulses, hence Franny’s loss of proprioception in her hind legs. Although possible that rest and anti-inflammatory medication would eventually resolve Franny’s condition, there was also a chance that the pressure on the cord would worsen and the situation could progress to complete and permanent paralysis. Early surgical intervention is considered the best treatment option in cases like this, and that’s what the specialists recommended for Fran.

Although Franny’s injury was the result of a car accident, similar intervertebral disc disease also occurs spontaneously, particularly in certain breeds including dachshund, beagle, Shih Tzu, corgi, and Pekingese. It can be chronic, with gradual onset and long course, or acute, with sudden onset. Presenting signs can range from mild back pain to paralysis. Deep pain perception still helps determine prognosis and MRI, definitive diagnosis.

Now when I was in school, we were taught to give most of these cases large doses of corticosteroids, which were thought to limit the inflammatory response in the spinal cord. Over the years different types of corticosteroids have come in and out of favor, and the entire concept has come into question. Nowadays it is not recommended as standard treatment, although corticosteroid use is still considered an option as long as possible side effects are weighed against possible benefits. Medical treatment and cage rest will suffice for many, but, as in Franny’s situation, early surgery is optimum for recovery in serious cases. One study indicated that more than 90 percent of dogs that had deep pain after acutely slipping a disk regained the ability to walk if treated promptly with appropriate surgery.

Franny had a procedure called a pediculectomy, which entails removing a little bone between the vertebrae, allowing access to remove damaged disk material and relieve the compression on the spinal cord, while maintaining the stability of her backbone. By the time she was discharged from the hospital, Franny could walk with the help of a belly sling. Rigorous postoperative supportive care is also essential and Franny’s owners were instructed to confine her to a crate or small room for 23 and a half hours a day for six to eight weeks. Not an easy task with a big, happy dog. When I went over to remove Franny’s staples 10 days later, mom was doing her best to keep Fanny from cheerfully wobbling around the yard, and doing the recommended physical therapy, gently extending and flexing each joint, going through a full range of motion to keep the legs flexible and strong.

We have high hopes Franny will recover completely, thanks to the emergency veterinarian’s prompt referral, the neurologist’s excellent diagnostics, the surgeon’s rapid intervention, and most of all, Franny’s owners’ willingness to go that extra mile for their dog.