Narrowing of Vertebral Canal in Dogs

In dogs, the spinal cord consists of 31 vertebrae or backbones, beginning from the head, consisting of 7 cervical (neck) 13 thoracic (chest) 7 lumbar (lower back), and 3 sacrum (pelvis), which ends at the tail. Cauda equina syndrome, or the latin term Horse’s Tail, is the pinching or compressional pressure within the nerve roots of the spinal cord in the lumbar and sacral regions of the spinal vertebrae. This  results in the narrowing of the vertebral canal known as lumbosacral stenosis.  It is known to be a congenital condition, and can also develop as an acquired condition with advancement of age.

Cauda equina syndrome is a progressive disorder that results in the final and remaining spinal nerve roots within the vertebrae being compressed, and can be a result of many various ailments.  Lumbosacral stenosis is defined as the narrowing of the vertebral canal which causes the inhibition of the free passage of the spinal cord and nerves.  These two terms are commonly used and very much related to one another, but are often mistaken to be synonymous.

• Mid-back pain
• Lower back pain
• Pain in the hind legs
• Pain in the tail 
• Nerve damage
• Restricted movement in affected areas
• Difficulty with balance and standing
• Poor posture
• Weakness or paralysis of the lower limbs and tail
• Struggling to urinate, and/or defecate
• Incontinence

Types

Cauda equina syndrome is known to affect dogs genetically susceptible to having disfigurement in their lumbar or sacral vertebrae.  It is known to be most often seen in small and mid-range size dogs such as Dachshunds and Beagles, and in larger dogs it is most prevalent in the German Shepherd, Rottweiler, and Boxer breeds.

Lumbosacral stenosis can be a congenital  disease, and it can also be acquired and developed later with age. Congenital attributes that are related include connective tissue disorder and bone abnormalities. Causes of this condition can be determined by many circumstances. 

• Accidental spinal injury or trauma
• Inflammation
• Infection
• Side effects of certain treatments and medications
• Neoplasia (cancer)
• Arthritis
• Scarring of ligaments  

This is a condition in where the bone cartilage (soft connective tissue that links joints and bones) degenerates over time.  The reason for this is the gelatin like substances which are crucial components of joint fluid have reduced greatly. In addition, dogs at risk have an inability to produce chondroitin, a major component of cartilage that is responsible for retaining water.

A physical examination will be conducted and your veterinarian will test and check reflexes in the hips and hind areas to assess joint mobility and the presemce of pain.  Diagnosis is easy to determine with the use of X-rays and dyes. The dyes act as a highlighter within the X-ray, known as epidurography and are accurate in identifying bone displacement, or disfigurement in the lumbosacral joint. Calcified ligaments confirm that lumbosacral stenosis is present.  Computed tomography, and magnetic resonance imaging (MRI) can detect the condition of the nerve roots and can also assist with visualization.

If the condition is mild, bed rest and anti-inflammatory medications will be ordered for up to 6-8 weeks. Surgery is a common procedure of treatment, in which the bones are reconstructed to normalcy as much as possible.  A second technique called dorsal laminectomy can also be done to remove part of the intervertebral disc and bones to alleviate the pressure on the nerves within the spinal cord. Glucosamine and chondroitin sulfate supplements are derived from cow, shark or shellfish cartilage and are extremely popular in treating arthritis and disc disease.  Chondroitin is reputed to block enzymes that destroy cartilage and may help retain water and reverse damage.

The prognosis and outcome of cauda equina syndrome is usually good.  Cage rest is recommended and if symptoms are mild, the use of medications is usually a sufficient means of treatment. If surgery is necessary and the condition is severe, surgery may only benefit by alleviating pain, but may not cure the problems of incontinence. The use of a swing has been proven to be a critical tool in rehabilitation, though you may have to assist your dog with sitting, getting up and walking to prevent falls.  Your veterinarian will monitor the prognosis of your dog and will provide you with instructions and information for additional rest and/or physical therapy to ensure proper recovery.