Having a Lumbar Puncture

Download and print as a PDF (306kB pdf)

What is a lumbar puncture?

A lumbar puncture (or LP) is a safe and commonly performed procedure in which a small needle is placed into your lower back and some of the fluid surrounding your spinal cord (cerebrospinal fluid or CSF) is taken for testing.

What happens during a lumbar puncture?

Before you have an LP, we will do a blood test to check that your blood is able to clot normally. During the procedure we will usually ask you to lie on your side with your knees curled up to your chest. We will clean your back with an antiseptic solution and you will receive a local anaesthetic injection to numb the area.

After this we will introduce a small needle into your lower back. We will collect some CSF, then we will remove the needle and we will put a clean dressing. The procedure usually takes around 30 minutes in total, but occasionally lasts a little longer.

Will it hurt?

The injection of local anaesthetic stings for a few seconds before the area becomes numb.

When we insert the lumbar puncture needle, most people describe the sensation as a strange or uncomfortable pressure, or pushing. It is rare to experience pain.

What happens afterwards?

If you are discharged from hospital after your LP:

• Walk around your bed area to make sure you feel well enough to go home.
• It is recommended that someone takes you home from hospital; you should avoid driving for 24 hours afterwards.
• You can remove the plaster from your back after 24 hours.

After the procedure another blood test may be required to interpret the CSF results. You will then be asked to change this to lie flat for a short time. Most people feel well after this time and resume normal activity.

When will I receive my test results?

Depending on which tests you need,it can take any time from a few hours up to a several weeks for your test results to come back.

What are the possible risks?

Unsuccessful procedure

Occasionally, the health care professional may be unable to obtain a sample of CSF due to technical difficulties. If this happens they may ask another qualified staff member to assist or arrange to have it done under x-ray guidance.

Headache

1 in 10 patients develop a headache after an LP. If you get a headache you should rest and lie down flat as much as possible. Some patients find that caffeinated drinks such as tea, coffee or cola help. If you need to take painkillers, paracetamol is best.

Normally the headache will settle down within a couple of days. Very rarely the headache can be severe and persist beyond 2 weeks, in which case you should inform your doctor.

Backache

1 in 6 patients have some backache following an LP. It is usually mild and settles over a few days. Again, paracetamol can be helpful.

Infection or Fever

The procedure is designed to be clean and safe. It’s very rare, but it is still possible to get an infection after an LP.

Bleeding and bruising

There is a small risk of bleeding and bruising when you have an LP.

Please inform the person performing your procedure beforehand if you take medications that thin the blood such as aspirin, clopidogrel, dipyridamole, warfarin, dabigatran, rivaroxaban, apixaban, tinzaparin, enoxaparin or heparin, or suffer from a medical condition that affects your blood or liver, as these can affect your risk of bleeding.

Nerve Damage

It is extremely rare for lumbar puncture to injure the nerves of the spine. Nevertheless, it remains a theoretical possibility.

Contact Information