Lumbar Puncture/Spinal Tap

What is a lumbar puncture?

A lumbar puncture, also known as a spinal tap, is a procedure to collect information about your medical condition. A needle is inserted into the lower part of the spinal column to collect cerebrospinal fluid.

Why is it ordered?

It is used to diagnose an infection, bleeding, a blockage, or tumor in your cerebrospinal fluid.  This procedure can also be used to administer chemotherapy into the cerebrospinal fluid and to the central nervous system or to drain cerebrospinal fluid to relieve pressure. 

Where is this done?

A lumbar puncture can be performed in your hospital room, an outpatient clinic, or vascular radiology in Duke University Hospital.

Do I need to do anything to get ready for this test?

No special preparations are needed before having a lumbar puncture. You will be asked to go to the bathroom and empty your bladder before the procedure begins.

What happens during the procedure?

You will be asked to lie close to the edge of the bed on your left side with your knees up to your stomach as far as possible. This position widens the space between the vertebrae (bones of the spine) so that there is more room for the needle to be inserted. A nurse will help you stay in this position if you are having difficulty.

The doctor, physician’s assistant, or nurse practitioner will then clean your back with a cool liquid soap. A numbing medicine will be injected into this area of your back. A needle will be inserted into the space between your backbone and your spinal cord.

Is this test painful?

You may feel a burning sensation temporarily when the numbing medicine is injected. You may also feel some discomfort or pressure throughout the procedure. It may help to take some slow deep breaths and try to relax during this time.

How long does it take?

The fluid collection only takes a few minutes. However, the total time for the procedure will take 30 to 45 minutes.

What happens after the procedure?

You will be asked to lie flat after the procedure and to drink lots of fluids, to reduce the risk of headache. Your doctor will specify the length of time, usually between 30 minutes and several hours. You will be able to get up to go to the bathroom. Your nurse will check your vital signs frequently and the site where the needle went into your back.

What are the risks with this procedure?

Your doctor will explain the risks and benefits of the procedure in your situation. In general, a lumbar puncture is a common and safe procedure. Here are some things to remember:

• A temporary headache is common after this procedure. Lying flat immediately following the procedure will help to prevent this. Tell your doctor if your headache persists or becomes severe.
• Whenever a needle is used, there is a slight risk of damaging tissue. Occasionally, some swelling or soreness may occur at the site. Your nurse will watch you after the procedure for more serious complications.
• Rare side effects include allergic reaction, particularly to the numbing medicine. Tell your doctor if you have any of these.

How will I get the results of this test?

Your doctor will discuss the results of the test with you. The results of the test may take a few hours to a few days, depending on the reason the test was performed.

This article is intended as a resource for patients receiving their cancer care at Duke University Hospital or Duke Clinic. It is not intended to substitute for medical advice from your healthcare team. If your doctor’s instructions differ from the information in this article, please talk with your doctor before making any changes. 

Source: Cancer Patient Education Program, Duke Patient and Family Education Committee, August 2003