Dog: Cauda Equina Syndrome

General information

Other common/scientific names: lumbosacral disease

A dog’s spine is composed of a long series of bones called vertebrae. These bones maintain the structure of the body and protect the spinal cord which is housed within the vertebrae. The vertebrae are connected through a series of ligaments. Between each vertebra are structures called disks which act as shock absorbers. The vertebrae are divided into sections based on their location, i.e. cervical (neck), thoracic (chest), lumbar (lower back) and sacrum (tailbone). The term lumbosacral defines the last lumbar vertebrae and the sacral vertebrae. In the dog, this area is just in front of where the tail attaches.

The cauda equina is defined as the bundle of nerves that extend beyond the termination of the tubular spinal cord in branches resembling a horse’s tail at the lumbosacral area. Cauda equina syndrome is degeneration and instability of the lumbosacral vertebrae causing pressure on the spinal cord and cauda equina nerves as they exit the spine.

Abb. GFQI9HXV: Illustration of the normal cauda equine.


Cauda equina syndrome is caused by arthritis, spondylosis, intervertebral disc disease, spondylitis, fractures or tumors. Congenital (present at birth) malformation or osteochondrosis of the spine may cause impingement of nerves. This cause is more commonly seen in German Shepherd dogs.

Abb. GFQIKM6J: Illustration of the possible causes of cauda equina syndrome.

Cardinal symptom

Back pain


Dogs with cauda equina syndrome show signs of worsening back pain, tail pain or pain in one or both hind limbs. The dog usually has difficulty rising when lying down and it is painful for the dog to raise or wag the tail. Dogs may have difficulty posturing to defecate or urinate. As nerve compression progresses, dogs may show signs of weakness, knuckling in the rear legs and paralysis. Dogs may develop fecal and urinary incontinence. Some dogs will mutilate their feet or tail with incessant chewing due to pain.


A complete physical and neurologic examination should be performed on all dogs showing signs of cauda equina syndrome. A neurologic examination helps determine which spinal nerves are affected by testing the nerve reflexes. Coupled with the examination, radiographs showing arthritis, spondylosis or intervertebral disk disease will lead to a presumptive diagnosis. However, a definitive diagnosis can only be made with a myelogram (a radiograph taken after a special dye has been injected into the space surrounding the spinal cord), magnetic resonance imaging (MRI) or computed tomography (CT). A myelogram can pinpoint the exact area of spinal cord compression. An MRI evaluates the disk and spinal cord, while at CT scan shows degeneration of the vertebrae. Myelograms, MRIs and CT scans are typically performed at universities or referral clinics specializing in neurology and orthopedics.

Abb. GFQITV3O: Cauda equina syndrome.
This is an MRI image of a dog’s lower spinal cord. The arrow points to an area where the spinal cord is compressed due to a diseased, bulging intervertebral disk.
Abb. GFQIVT9E: Cauda equina syndrome.
This is a radiograph showing degenerative changes in the spine. The red arrows point to diseased endplates of the last lumbar vertebra and the first sacral verterbra.
Abb. GFQIXRAH: Cauda equina syndrome.
This is a myelogram of a dog with cauda equina syndrome. The white arrows point to the outline of the spinal cord. Note the compression or narrowing of the cord at the distal (lower) lumbar vertebra.


Medical treatment consisting of rest and anti-inflammatories/ analgesic medications can be used in dogs with mild pain. Alternative therapies of massage, physiotherapy and acupuncture are used to provide pain control. Antibiotics are used in cases of diskospondylitis.

Dogs with more severe pain, recurring bouts of pain or nerve damage may require surgery. Two different procedures are used depending on the dog and cause of the clinical signs. A dorsal laminectomy is performed which involves removing part of the vertebral bone compressing the nerves. Removal of any diseased disks is also performed with the laminectomy. The other procedure involves fusing the lumbosacral vertebrae to prevent abnormal motion and thus damage to the spinal cord.

Strict exercise restriction is necessary for three to six weeks post surgery. After this time, activity is gradually increased. Weight should be reduced in overweight dogs.


The prognosis depends on the severity and duration of clinical signs. Dogs with mild to moderate pain and mild nerve damage can respond well to surgical treatment. Dogs with severe nerve damage causing urinary and fecal incontinence and paralysis have a guarded prognosis.


While cauda equina syndrome cannot be prevented, maintaining a normal, healthy weight in your dog can reduce the clinical signs.

Update version: 4/24/2014, © Copyright by
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