INTERVERTEBRAL
DISEASE
Cheryl L. Chrisman, DVM, MS, EdS |
The spinal column begins at the base of the
skull and ends at the tip of the tail creating
the neck and backbone of the4 dog. The spinal
column is formed by seven cervical, thirteen
thoracic, seven lumbar, three sacral and usually
five or more caudal (tail) vertebrae that are
held together by ligaments and muscles. The
vertebrae are each numbered for reference like
C1-7, T1-13, L1-7, S1-3 and Cd1-5. This way
problems can be localized along the spinal
column as occurring at C5, T12, L7, etc. Each
vertebra has a hole in the middle so as the
vertebrae align with each other a channel call
the spinal canal is formed and runs the entire
length of the spinal column.
The spinal cord is a thick cable of nerves that
begins at the base of the brain inside the skull
and extends through the spinal canal. The
relationship of the spinal cord and vertebrae
are much like a string running through the beads
of a necklace where the string is the spinal
cord and the beads are the vertebrae. The spinal
cord carries all the nerves going to and from
the brain that make the legs and other
structures function properly.
The intervertebral (IV) disc is a spongy cushion
that is located between the vertebrae just below
the spinal canal and spinal cord. The IV disc
acts like a shock absorber and adds flexibility
during movement of the spinal column. There are
approximately 34 IV discs throughout the entire
neck and back. Each IV disc consists of an outer
tough ring that has a soft gelatinous center
much like a day old jelly filled donut.
IV disc disease is a degeneration of the disc
that can occur due to premature or normal aging
specific to certain breeds of dogs. A
degenerating IV disc can rupture and spill its
contents into the spinal canal (Type I disc
herniation). This is often referred to as a
slipped disc and can irritate, bruise or
compress the spinal cord causing sudden pain or
paralysis. A degenerating IV disc can also
enlarge and slowly push up into the spinal canal
(Type II disc disease) and put pressure on the
spinal cord or nerve roots which enter and exit
the spinal cord causing a slow progressive
staggering gait, weakness in the legs or
complete limb paralysis. Type I intervertebral
disc herniation will be discussed here.
Type I intervertebral disc degeneration is
common in many breeds of dogs at any age such as
Dachshunds, Pekingese, Poodles, Maltese, Cocker
Spaniels, Shi Tzus, Lhasa Apsos, Pugs and
Beagles. The diagnosis is suspected based on the
breed, history and clinical signs but tests such
as spinal radiographs, cerebrospinal fluid
analysis, myelogram and computerized axial
Tomography or magnetic resonance imaging scans
may be necessary to confirm the diagnosis.
If pain or mild limb weakness is the only sign
then muscle relaxants, steroids and rest are
prescribed for 2-4 weeks. The most difficult yet
most important part of the treatment for mild IV
disc disease is absolute rest. The medication
may make them feel great and it is easy for dog
owners to think their problems are over and this
can lead to sudden paralysis. Rest often
requires a major change in the family’s routine,
as dogs must be confined to a crate or small
room and not be able to play with their toys or
other dogs. Further they must be taken briefly
outside on a leash for urinations and
defecations with no other exercise. Small dogs
can be held and cuddled and carried, but no
exercise.
Going up and down stairs, jumping on and off the
bed or other furniture and sitting up to beg can
cause the degenerating discs to rupture and
paralysis can occur. Weight reduction may be
necessary in obese dogs to reduce stress on the
spinal column. With rest it is hoped that the
degenerating IV disc will heal somewhat and the
part that is extruded into the spinal canal will
spread out and move away from the spinal cord
relieving the pain or weakness without surgery.
Many dogs with back pain will completely
recover. They may have a recurrence of problems
from the same or some other IV disc later in
life. Dogs with neck pain usually have to have
surgery as signs persist after rest and
medications.
It is recommended that dogs that are at high
risk for recurrence of IV disc disease be put on
antioxidant drugs such as: Vitamin E 100-200 IU
and Vitamin C 100-200 mg for a 10-30 lb dog.
There has been some research done to show that
antioxidants will protect the spinal cord to
some degree in cases of injury. These vitamins
can be found in any drug or health food store
and a special dog formulation is not required.
Going up and down stairs, jumping on and off the
bed or other furniture, sitting up to beg,
playing fetch or Frisbee and other games require
sudden turns to the spinal cord or agility work
should be avoided in the future to prevent
recurrences. Sometimes no matter how well the
weight and life-style are controlled other IV
discs can cause problems.
Acute explosion of a degenerative IV disc can
cause sudden paralysis of the legs, which is a
surgical emergency. A rapid acting steroid such
as methylprednisolone sodium succinate or
prednisolone sodium succinate should be
administered intravenously as soon as possible
after the onset of paralysis and then immediate
referral to a specialist who performs
decompressive surgery is essential. Treatment
within the first 25 hours is the most crucial
and after that time all treatments will be less
effective. Approximately 80 percent of all dogs
with acute paralysis given immediate rapid
acting steroids and surgery within 24 hours are
eventually able to walk again. Preventative
surgery may be done to reduce the incidence of
future problems at the same time.
After surgery most dogs need a rehabilitation
time of 1-6 months but will continue to get
stronger for 12 months. Most dogs cannot walk
immediately even after surgery because the
spinal cord has been bruised from the exploding
disc. Most paraplegic dogs canoe urinate for
several days. Usually they have to stay in the
hospital to have their bladders manually emptied
otherwise the bladder could be permanently
damaged. Once they can urinate they are returned
home as most dogs heal faster at home. At home
simple physical therapy such as bending and
moving the limbs through their normal range of
movement and gentle massage will help keep limbs
supple until the nerve function returns.
Movement and massage in shallow warm water in
the bathtub or sink can be great physical
therapy, if the dog owner has the time. Fifteen
minutes twice daily can be helpful. By using a
sling made from a wide belt or towel they can be
exercised with support. Some movement begins to
return to the limbs within four weeks after
surgery.
In cases of severe spinal cord injury, paralysis
can be permanent. Some owners may elect to try a
cart with wheels that supports the hind legs for
exercise purposes. I suggest they try the cart
for a month and see how they think their dog’s
quality of life and how the household adjusts to
a
paraplegic dog. Many dogs and families adjust
fine. However dogs cannot live in the cart as
they cannot lie down. The bladder must be
emptied completely and urine samples monitored
by a veterinarian for infections. Bladder
infections, which then damage the kidneys is the
most life threatening problem in paraplegic
dogs. Most dogs with IV disc disease recover and
with a few lifestyle changes lead happy lives.
|
 |
| |
|
|
| |
|
