Lumbar Puncture (Spinal Tap)

What is a lumbar puncture (spinal tap)?

A lumbar puncture (spinal tap) is a procedure where a healthcare provider inserts a needle into your lower back to remove a sample of cerebrospinal fluid. Cerebrospinal fluid is the clear fluid that surrounds your spine and brain.

This test can help diagnose conditions that affect your brain, nerves and spinal cord.

Why is a lumbar puncture (spinal tap) performed?

Your healthcare provider may perform a lumbar puncture to test for:

• Bleeding in your brain (intracranial hemorrhage).
• Dementia.
• Excess cerebrospinal fluid.
• Inflammation of brain tissue (encephalitis).
• Leukemia or other cancers.
• Meningitis (brain infection).
• Multiple sclerosis or other autoimmune conditions.
• Myelitis (spinal cord inflammation).

Healthcare providers also use a lumbar puncture (spinal tap) to:

• Administer regional anesthesia, such as an epidural to block pain in the lower part of your body.
• Inject dye for an X-ray diagnostic test (myelogram).
• Inject cancer medications or muscle relaxers.
• Relieve intracranial (within your skull) pressure.

This isn’t an exhaustive list of all conditions and reasons for the procedure. Your healthcare provider can give you the best information as to why they need to perform this procedure.

How do I prepare for a lumbar puncture (spinal tap)?

If your healthcare provider schedules a lumbar puncture, they may recommend the following before your test, in addition to a physical exam and learning more about your health history:

• Getting a CT scan or MRI.
• Getting a blood test done.
• Stopping or changing your medication schedule if you take blood thinners like warfarin or aspirin. Don’t make changes to your medication routine unless your healthcare provider approves it.

These preparations help your healthcare provider learn more about the area of your body that they’ll be looking at during the procedure, make sure it’s safe for you and take steps to prevent complications.

Your provider will give you specific or additional instructions to help you prepare.

What happens during a lumbar puncture (spinal tap)?

For a lumbar puncture, a healthcare provider will instruct you to lie on your side (usually the left side). You’ll need to pull your knees to your chest when they’re ready and stay in that position for the length of the test. Or you may sit and lean forward with your arms and head resting on a table. While this position may be awkward or uncomfortable, it’s important that you stay as still as you can and follow their instructions. You may need to change your position slightly during the procedure.

Next, your provider will clean your skin and numb the area of your lower back with a local anesthetic. You might feel a slight burning sensation when you get the anesthesia. You won’t feel any pain during the procedure, but you may feel pressure.

When the area of your body is numb, your provider will insert a thin, hollow needle in between two vertebrae (usually the third and fourth lumbar vertebrae). This is in your lower back above your buttocks. The needle will move into the subarachnoid space or the area between your spinal cord and the meninges (membrane layers that cover your spinal cord). Your provider may use an X-ray called a fluoroscopy to help guide the needle to the correct spot.

Once the needle is in place, your healthcare provider will measure spinal fluid pressure and remove a sample of cerebrospinal fluid.

When your provider completes the procedure, they’ll remove the needle and put a bandage on your skin.

Where does a lumbar puncture (spinal tap) take place?

Depending on your situation, a spinal tap may take place as an outpatient procedure (you go home the same day) in a medical office or in the hospital. If you have an outpatient procedure, someone needs to drive you home afterward.

Will I be asleep during a spinal tap?

No. You’ll receive local anesthesia, not general anesthesia, so you’ll be awake during the procedure. But you won’t feel any pain.

How long does a lumbar puncture (spinal tap) take?

A lumbar puncture takes about 15 to 30 minutes from start to finish. The needle is only in your back for a few minutes.

What can I expect after a lumbar puncture (spinal tap)?

After a lumbar puncture, your healthcare provider will give you instructions to take care of yourself. This may include the following after the procedure:

• Not driving or operating heavy machinery for 24 hours.
• Lying on your back or side for at least one hour to a few hours.
• Avoiding strenuous activities or exercises for 24 to 48 hours.
• Getting plenty of rest.
• Drinking plenty of fluids to stay hydrated.

With your provider’s OK, you may be able to return to work after a spinal tap.

Are headaches common after a lumbar puncture (spinal tap)?

About 10% of people who get a lumbar puncture develop a spinal headache. This feels like intense pain when sitting or standing. A headache may come on within hours or several days after the procedure. The pain typically goes away on its own in a couple of days, but it may linger for a week or more. Along with the spinal headache, you may experience:

• Fast heart rate (tachycardia).
• Low blood pressure (hypotension).
• Nausea.

Over-the-counter pain medicines, staying hydrated and drinking caffeinated beverages can help.

What are the side effects of a lumbar puncture (spinal tap)?

Side effects after a lumbar puncture are rare and may include:

• Infection.
• Swelling.
• Bleeding.
• Lower back pain.

There’s no risk of spinal cord damage after a lumbar puncture. Your cord sits higher than the area of the lumbar spine area where the spinal tap takes place.

What type of results can I expect after a lumbar puncture (spinal tap)?

A lab tests the cerebrospinal fluid sample after a lumbar puncture to check for:

• The presence of bacteria, fungi or abnormal cells.
• Glucose (blood sugar) levels.
• Protein types and levels.
• White blood cell types and levels.

These results help your healthcare provider rule out and diagnose possible conditions.

When should I know the results of a lumbar puncture (spinal tap)?

The timing of spinal tap results depends on the reason for the test. On average, you should get your results within two to three days. If you need an emergency spinal tap to check for life-threatening conditions like a brain bleed or meningitis, you’ll get your results sooner.

If the results are abnormal what are my next steps?

As a spinal tap helps diagnose multiple possible conditions that affect your brain, nerves and spinal cord, results vary based on what they show. For example, if you have a high white blood cell count, you may have an infection. Antibiotics can treat the infection so you feel better.

Your healthcare provider will explain what your results mean and what the next steps are to treat any underlying conditions.

When should I call my healthcare provider?

You should call your healthcare provider if you experience:

• A headache that’s extremely painful and lasts more than a few days.
• Bloody discharge or drainage at the puncture site.
• Signs of infection, such as swelling and a fever.