Spinal Arachnoid Cysts

About Spinal Arachnoid Cysts

Spinal arachnoid cysts are noncancerous pockets of spinal fluid that form due to an abnormal separation of the tissue membrane that surrounds the spinal cord, called the arachnoid mater. The cyst is usually filled with cerebrospinal fluid (CSF). Sometimes they occur in response to inflammation after trauma or other event. They can grow and put pressure on nerves within the spinal canal.

There are two types of arachnoid spinal cysts: primary and secondary. Primary cysts are present at birth ,while secondary cysts develop later in life. Primary cysts are more common, and men are more likely to develop the cyst than woman. The exact cause of primary cysts is unknown. Secondary cysts are caused by trauma, meningitis, and tumors.

Many times, these cysts are asymptomatic (have no symptoms), but some can produce pain and/or neurological symptoms such as weakness, numbness, and balance problems. Surgery involves opening the cyst, making holes in, or fenestrating, the cyst to allow fluid to move freely. Arachnoid cysts can be treated with open or minimally invasive techniques.

Common Symptoms of Spinal Arachnoid Cysts

While some spinal arachnoid cysts are asymptomatic, some produce symptoms. Common symptoms include:

  • Back pain
  • Leg pain
  • Tingling in the arms or legs
  • Muscle spasms/weakness
  • Walking difficulty
  • Problem controlling bowel/bladder

Diagnosis of Spinal Arachnoid Cysts

Image testing is required to properly diagnose a spinal arachnoid cyst. Usually the cyst can be detected with an MRI scan, that is also useful to rule out any other conditions.

Treatment Options for Spinal Arachnoid Cysts

If the arachnoid cyst has no symptoms it may not be treated. Doctors may choose to monitor it over time for changes. If the cyst is problematic, surgery is the treatment of choice. Rarely, the cyst cannot be removed and requires drainage or shunting with insertion of a tube from the cyst to an open body cavity.