Cauda equina syndrome (CES) is a rare disorder affecting the bundle of nerve roots, known as the cauda equina, that arise from the lower or lumbar end of the spinal cord and fill the space in the bony spinal column below the spinal cord. An extension of the brain, these nerves send and receive messages to and from the pelvic organs and lower limbs. CES occurs when these nerve roots are compressed, affecting function of the pelvic organs and sensation and movement in the legs.

CES most commonly results from a massive disc herniation in the lumbar region, which occurs when the soft, flexible core of one of the discs that functions as a shock absorber between the bones of the spinal column "ruptures" or herniates from its normal position, pressing on the nerve roots.

Besides a herniated disc, CES may also be caused by pressure on the nerve roots from a tumor, an infection, a fracture or narrowing of the spinal canal, called spinal stenosis. The syndrome may also occur because of major trauma to the lower back, such as from a car crash, a fall, or a gunshot or stabbing.

CES is accompanied by a range of symptoms, the severity of which depend on the degree of compression and the precise nerve roots that are compressed. Symptoms can include severe low back pain, urinary or bowel incontinence, muscle weakness or loss of sensation in both legs, and "saddle anesthesia" (the inability to feel anything in the body areas that would sit on a saddle).

Because the syndrome is so rare and its symptoms mimic those of other conditions, CES is difficult to diagnose. Additionally, symptoms may vary in intensity and evolve slowly over time. Diagnostic tools valuable in discovering CES include:

· Magnetic resonance imaging (MRI) - energy from a powerful magnet producing a series of three-dimensional views of parts of the back. An MRI is particularly sensitive for detecting damage or disease of soft tissues, such as the discs between bones in the back. It also clearly shows the spinal cord, nerve roots and surrounding spaces.

· Computerized axial tomography (CAT or CT scan) - x-rays are passed through the back at different angles, producing a series of images or three-dimensional views of the parts of the back. The scan shows the shape and size of the spinal canal, its contents and surrounding structures.

· Myelogram - a liquid dye is injected into the spinal column and circulates around the spinal cord and spinal nerves, showing pressure on the spinal cord or nerves from herniated disks, bone spurs or tumors.

Without treatment to relieve the pressure, CES can cause permanent paralysis, impaired bladder and bowel control, loss of sexual sensation and other problems.

For more information, visit the Cauda Equina Syndrome Support Group Web site.