CAUDA EQUINA SYNDROME
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http://www.petsurgery.com/caudaequinasyndrome.html
The article follows this introduction.
At a conference I attended a few years ago, CES was discussed
extensively. The orthopaedic/neurological surgeons stated very
clearly that the best outcome for CES was acheived by spinal
surgery to relieve the pressure on the nerve bundle. They also
stated that a "dead" tail is the definitive symptom of CES.
There are degrees, of course, of CES, but my understanding is
that if the tail is affected, early surgical intervention is
imperative. If intervention is not done early enough, bowel and
bladder dysfunction is the next step in the progression of the
disease.
Is the disease considered genetic? Yes, it is considered to
be an inherited malformation of the spine. The area of the spine
that is affected, is not an area of the spine that is exposed to
injury. Exercise can make the symptoms worse, but exercise is
not the cause of the CES.
This "ins and outs" of this disease may not be well known to
many vets because it is not a disease that they run into every
day. As Judy will tell you, Kyra's tail was xrayed and examined
by several doctors who were not familiar enough with the disease
to catch it.
Your best place to go for a definitive diagnosis is to a
Veterinary Orthopedic Surgeon.
This disease cannot be diagnosed by regular xrays, because
the part of the spine that is affected is "hidden" from view. It
is that area of the spine that is between the "hip bones". An
MRI or CT scan, however, will reveal the cause of the CES.
MRI and CT scans are expensive. A surgeon or veterinarian
that is familiar with the disease can make a pretty good
diagnosis on the strength of the "history" of the problem, pain
at the base of the tail, a "dead" tail and neurological
examination of the hind legs. What separates CES from other
neurological diseases is "pain"!
CAUDA EQUINA SYNDROME
DEGENERATIVE LUMBOSACRAL STENOSIS
(LOWER BACK PAIN)
Degenerative lumbosacral stenosis generally involves a compression
of the nerve roots in the lower back. Most dogs affected by
lumbosacral degeneration are middle aged or older members of the
larger, athletic breeds. As a rule, these breeds are very
tolerant of discomfort until it eventually overrides their
character and results in clinical manifestations.
The most common, and often the only, symptom is progressive
sharp pain. However, this syndrome can manifest itself in a
number of ways.
Intermittent lameness in one or both pelvic (rear) limbs or a
stilted gait is a common initial sign. The patient may
progressively have more difficulty rising from a prone position
or may be unusually reluctant to leap. The dog may act suddenly
(but often transiently) painful or lame immediately after
getting up or jumping. Strenuous activity may exacerbate the
signs. Vocal expression of pain may vary from moans or whimpers
when the dog tries to rise, to sharp cries to howls when touched
over the rear quarters or making a wrong move during exercise.
Eventually, even the most stoic (pain tolerant) individuals will
react to the exquisite, burning pain of the nerve root
entrapment caused by this syndrome. Chewing at the tail or rear
feet and bowel and bladder incontinence may be seen in advance
cases where severe pressure of the nerve roots causes the
burning sensation described as "sciatica". The most devastating
cases can evolve to full paralysis.
DIAGNOSIS
The neurologic examination begins by observing the gait. Specific test
for pain and neurologic dysfunction are then performed to
confirm the site of the lesion.
Individual with hip dysplasia will often show a mild response
to hip extension, whereas dogs with lumbosacral disease will
object more acutely to hip extension and cry when pressure is
added to the lumbosacral junction (Fig.1). Manipulation and
hyperextension of the tail causes an exquisite pain response.
The spinal reflexes are tested, including the perineal reflex
and anal tone, to assess the early signs of nerve root
entrapment that lead to incontinence.
Nerve root entrapment and pressure can result from an
arthritic process, infection, a degenerative disc rupture, or
tumors. Therefore, it is essential to accurately diagnose your
pet's individual problem before considering treatment (Fig 2&3).
This requires radiography (x-rays).
Plain radiographs can be taken under general anesthesia and
are very difficult in diagnosing syndromes such as infection,
trauma, severe arthritis or bone neoplasia. A definitive
diagnosis may require special x-ray tests. A myelogram or
epidurogram (contrast dye studies of the spine) are used to
confirm and document not only the location of the lesion but
also the dynamic position of the ruptured disc in relation to
entrapped nerve roots as the spine is flexed and extended. With
new gas anesthetics, advanced monitoring equipment, and modern
"contrast" agents for the dye study, the myelogram and
epidurogram are now common and safe diagnostic procedures when
performed under the proper conditions. In difficult cases, MRI
or CT scans are available and are of exceptional diagnostic
value.
Electromyography (EMG) may be of value in substantiating the
diagnosis and the severity and symmetry of nerve root entrapment.
TREATMENT
Medical therapy (consisting of rest and anti-inflammatory/ analgesic
medication) should be tried in patients with the first episode
when experiencing mild pain only.
Indications for surgical intervention include neurologic
deficits, pain unresponsive to proper conservative treatment,
and frequent recurrences to pain, even if the episodes respond
well to medical treatment. To relieve pressure on the entrapped
roots a dorsal laminectomy is performed. This involves removing
portions of the bony canal entombing the entrapped nerve roots.
This conservative laminectomy adequately exposes the nerve roots
and allows the surgeon to safely retract them for exposure of
the disc space. The cauda equina is gently retracted to one side
with blunt nerve hooks, exposing the herniated discs as a large
dome on the floor of the spinal canal. The herniated disc is
excised, compressive osteophytes removed, and formenotomies
(opening the nerve root canals) performed to relieve root
entrapment. Once the pressure s relieved, the neurologic
function gradually returns as the nervous tissue heals in its
decompressed environment.
POSTOPERATIVE CARE
A course of rest is the most important component of postoperative care.
All strenuous and acrobatic activity should be curtailed for at
least 6 weeks. At that time, the exercise level is gradually
increased. If the dog is obese, weight should be reduced.
The prognosis depends on the severity and chronicity of
clinical signs before surgery. Dogs with pain, reluctance to
jump, or tenderness upon getting up as their only symptom will
usually improve rapidly and dramatically. Some patients may have
an occasional, transient painful episode. Dogs with chronic
neurologic dysfunction will take much longer to improve, and
they may never return to completely normal function. However, at
the very least they will return to a pain free lifestyle.
© 2002 Southern California Veterinary Referral Group |