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(Cerebrospinal Fluid Analysis; Cerebrospinal Fluid Tap; Spinal Tap)
A lumbar puncture is a test of the fluid around your spine and brain. This fluid is called cerebrospinal fluid (CSF). It provides protection and nutrition to the brain and nerve cells. CSF also helps to remove waste products from the brain.
|Lumbar Puncture Method|
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Reasons for Procedure
The test is done to look for anything abnormal in the CSF. It may be done to help diagnose conditions such as:
- Brain infection, or infection of the layers around the brain
- Multiple sclerosis (MS)
- Any disorder affecting the nervous system
- Certain types of cancer
- Bleeding in the brain or spinal cord
- Excess CSF in the brain
The procedure may also be done to:
Problems from the procedure are rare, but all procedures have some risk. The doctor will review possible problems, like:
What to Expect
Prior to Procedure
Early tests including blood work, CT scan or MRI scan may be reviewed. You may be asked not to eat or drink anything after midnight the night before.
The doctor will need to know about any medicine you are taking or any allergies.
Local anesthesia will be used most often. It numbs just a small area.
Description of Procedure
You will likely lie on your side with your knees drawn up in front. Some punctures may be done while you sit on the edge of the bed. The site where the needle will be inserted will be cleaned. A needle will be inserted through the lower back and into the spinal canal. A sample of CSF will be taken through the needle.
The pressure of the CSF may be noted during the procedure. The needle may need to be repositioned if it is causing pain. It may take several minutes to collect the fluid that is needed. The needle will be removed. A dressing will be placed over the site.
Immediately After Procedure
You will lie down for 10 to 60 minutes. You will often be able to go home after the procedure. If you have a severe headache or need immediate treatment, you may need to stay longer.
How Long Will It Take?
About 30 to 45 minutes from setup to completion
Will It Hurt?
A lumbar puncture can be uncomfortable. The anesthesia will sting when it is first injected.
Rest and self care will be needed for at least 24 hours.
Call Your Doctor
Talk to your doctor if recovery is not going as expected or any of the following occurs:
- Severe headache or headache lasting for more than 24 hours
- Nausea or vomiting
- Signs of infection, including fever and chills
- Redness, swelling, increasing pain, bleeding, or discharge from the lumbar puncture site
- Numbness, tingling, or pain in your lower back or legs
- Weakness in your lower legs or difficulty walking
- Problems passing or controlling urine or stool
- A stiff neck
- Pain is not controlled with the medicine that was given
If you think you have an emergency, call for medical help right away.
Family Doctor—American Academy of Family Physicians
National Institute of Neurological Disorders and Stroke
About Kids Health—The Hospital For Sick Children
Doherty CM, Forbes RB. Diagnostic Lumbar Puncture. Ulster Med J. 2014 May;83(2):93-102.
Lumbar puncture (LP). EBSCO DynaMed website. Available at https://www.dynamed.com/procedure/lumbar-puncture-lp/ . Updated March 27, 2019. Accessed March 14, 2019.
Lumbar puncture. Radiological Society of North America Patient website. Available at: https://www.radiologyinfo.org/en/info.cfm?pg=spinaltap. Updated April 30, 2018. Accessed March 14, 2019.
- Reviewer: EBSCO Medical Review Board Rimas Lukas, MD
- Review Date: 03/2019
- Update Date: 03/14/2019