Cervical disc disease involves the acute or chronic pressure of material from an intervertebral disc pressing on or around the spinal cord in the area of the neck. This condition may be referred to as Intervertebral Disc Disease (IVDD) that occurs in the cervical area of the neck.
The exact cause of disc degeneration is unknown but in many cases there is a change in the content of the disc from a soft, pliable gel to stiff mineral that can slowly compress the spinal cord or suddenly burst into the spinal canal. Discs in the cervical region of the spine can affect the front legs and the back legs to varying degrees. This disc disease can affect one side of the body or both sides.
Dogs may show only mild neck pain all the way through to complete paralysis of all four legs without the ability to perceive any sensation whatsoever. Sudden onset neck pain is the most common clinical sign.
Chondrodystrophic breeds such as dachshunds and Pekingese are among the breeds more commonly affected. There is a higher incidence in beagles. Most dogs are middle aged and there is no sex predilection.
Signs of cervical area Intervertebral Disc Disease (IVDD) in dogs may include:
If your dog can walk normally but has back pain, your veterinarian will palpate the spine by applying gentle pressure to it to try to locate the affected area.
If your dog can walk but is clumsy, your veterinarian will check to see that only the back legs are affected and the front legs and head are normal.
If your dog cannot walk, your veterinarian will pinch the toes of the back legs to assess your dog's awareness of pain. Your dog may pull the leg back as a reflex response (the withdrawal reflex); however, your veterinarian will want to see if your dog cries out or tries to bite, indicating that he feels pain in the affected limbs. Just pulling the leg back does not indicate that your dog can feel his legs.
The type of appropriate treatment will depend on the severity of the clinical signs. Dogs with milder forms of the disease may be treated medically, whereas more severe cases may need surgery. Treatment may include one or more of the following:
Strict cage rest will be essential for at least four weeks when opting for medical management. This rest is essential to allow a scar to form over the top of the disc material; early activity may precipitate the herniation of the rest of the disc material and worsening of your dog's condition. Failure to confine a dog with disc herniation is a common reason for early recurrence.
If your dog is unable to urinate on his own, he will need help emptying his bladder. When the bladder overfills, urine dribbles out, but this results in stretching of the bladder and may make your dog unable to urinate even if there is improvement in the condition of the spinal cord. Bladder emptying is usually done three to four times a day. If your dog is released from the hospital while he is still having difficulty urinating be sure that your veterinarian shows you how to empty the bladder (called “expressing” the bladder).
If your dog is unable to walk, physical therapy is important to promote muscle strength. Have your veterinarian or the veterinary staff show you how to do this.
Be prepared for small increments of improvement. Depending on the severity of the disease your veterinarian will estimate how long your dog's recovery may take. Most likely your dog won't walk immediately away after surgery. Just as in people, it takes time to recover from spinal cord injury, so be patient.
Observe your dog closely for any worsening of clinical signs. If you notice any deterioration in your dog's condition, contact your veterinarian immediately. If he is predisposed to back problems be aware of the early signs of disc disease. If he shows any sign that might indicate a neurologic problem, seek veterinary advice as soon as possible.
The combination of your dog's breed, history of clinical signs and the veterinary examination will be suggestive of a cervical spinal problem. In the neck region, disc disease would be the most likely cause of a spinal disorder, particularly in 4 to 9 year old chondrodystrophic breeds of dogs.
After taking a detailed history, your veterinarian will perform a general physical examination, which is usually normal aside from cervical pain. Ability to flex and extend the neck is noted together with range of motion to the left or the right.
If your pet cannot walk even with support the toes of all four legs are pinched, either with fingers or often with an instrument called a hemostat to clamp down on the toes. This may look barbaric but is very important to define the severity of the spinal cord injury. If your dog feels the stimulus, he or she should cry out or try to turn around and bite. If your dog does not feel the pinch, this is an indication that deep pain sensation has been lost. This is the most severe type of spinal injury.
It is important to note that pulling the leg away when the toe is pinched does not mean that your pet feels the pain. This is just the “withdrawal reflex” and not conscious sensation of pain. Crying or biting suggests that the information from the toe being pinched got past the damaged region and was received by the brain; pulling away does not.
Your veterinarian will feel for your pet's bladder and check the muscle tone in the anal region. These sites could be affected by spinal cord injury.
Your veterinarian will be trying to define whether the muscle tone and reflexes in the front legs are reduced or exaggerated. Reduced activity may suggest that the neck lesion lies in the region of the brachial plexus or lower cervical area, whereas exaggerated activity would indicate a higher neck injury.
At the end of the examination your veterinarian will be able to define the location of the injury, the severity of the problem and make recommendations about how best it should be treated. Obviously, the more marked the damage to the spinal cord, the more severe the effects on the legs and the worse the prognosis. The longer this damage has been present the worse the prognosis.
The choice of medical versus surgical treatment will depend on the severity of the problem.
For dogs with mild neck pain, or very mild neurological signs such as clumsiness, that still retain the ability to walk, medical management can be an appropriate course of treatment. This involves strict cage rest and the use of medications such as muscle relaxants and steroids. Your dog may be hospitalized and given a course of intravenous steroids, or may receive a course of oral steroids that taper off over a number of weeks when your dog goes home.
The common steroid used is prednisone and this usually results in increased thirst, urination and appetite. Some dogs can also become very excitable. Medical management has been reported to fail in about 33 percent of dogs in one study.
When neck pain is severe, fails to respond to medical options or produces significant neurological problems in the legs, surgery is indicated. A myelogram, CT scan or MRI are performed to locate the exact disc space affected. A small window of bone is drilled in the underside (ventral aspect) of the spinal bones (ventral slot) on either side of the affected disc space. This allows access to the ruptured disc material and its removal from the spinal canal.
Your pet will not be cured instantly by the surgery. The procedure takes the pressure off the cord, allowing it the opportunity to heal but does nothing directly to the cord itself. It has to heal on its own. Fortunately, however, the spinal canal is at its largest through the neck region such that the cord is more tolerant of extruded disk material. Recovery is usually quicker here than for disc disease at the thoracolumbar site, for example.
Following surgery, dogs are hospitalized for several days to assess their early improvement and to determine the level of bladder function.
Most dogs that receive cervical disc surgery to not have problems urinating but if necessary your vet will show you how to hold your dog to compress and empty the bladder. Medication may be used to help with bladder function.
You will need to check the incision on the underside of the neck daily for swelling redness or discharge. Stitches or staples must be removed in two weeks.
Most dogs continue to have control of their bowel movements but occasionally may need assistance to stand to defecate. If you can, support your dog to encourage a more normal bowel movement. Make sure their back end stays clean.
Passive range of motion may be encouraged if your dog is taking a little longer to recover. This involves shoulder, elbow, hip and stifle flexion and extension exercises to promote good muscle tone and joint mobility in order to offset muscle wasting.
For dogs that are unable to walk, soft padded bedding is very important, and turning him frequently from side to side, at least four times a day, can help prevent the development of pressure sores.
All dogs following spinal surgery need rest and confinement for a period of four to six weeks, even if they appear to be moving well. This allows the tissue around the surgical site to heal.