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Multiple Sclerosis and the Spinal Tap

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What Happens During a Spinal Tap?

You will be asked to lie on your side with your knees drawn as close to the chest as possible or to sit with your arms and head resting on a table.

Your skin around your lower back will be cleansed and covered. You will be given a local anesthetic to numb the area. A long, thin hollow needle is then inserted in your low back between two bones in the lower spine and into the space where the CSF is located. The spinal canal is entered and fluid is collected. One to two tablespoonfuls of fluid are withdrawn. The spinal cord is never touched.

After the fluid is collected and the needle is removed, you will be asked to lie on your back or stomach for a few hours.

Your blood may be drawn and sent to the lab with the spinal fluid.

What Happens After a Spinal Tap?

After a spinal tap, your doctor may recommend that you lie down for several hours after the procedure to prevent a spinal headache. If you develop a headache, lie down as much as possible and drink plenty of fluids.

Avoid strenuous or vigorous exercise for a day or so following the spinal tap.

Is a Spinal Tap Safe?

Yes, a spinal tap is safe; however, as with most tests, there are a few minor risks. These include:

  • Headache. Approximately 10% of people develop a spinal headache (one that worsens when sitting or standing and is instantly relieved by lying down).
  • Infection. The risk of infection is extremely low.
  • Bloody tap. Occasionally, a small blood vessel is pierced during the procedure, causing a "bloody tap." No treatment is needed, but in some cases, the spinal tap will need to be repeated at a later date to get a "clear" sample.


Call your doctor immediately if you notice any unusual drainage, including bloody discharge, or worsening pain symptoms.

WebMD Medical Reference

Reviewed by Richard Senelick, MD on February 25, 2015
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