This test looks at the fluid called cerebrospinal fluid (CSF) that surrounds the brain and spinal cord. Lumbar punctures are done for a number of different reasons. They can be done to look for diseases of the brain and nervous system, or to look for cancer cells or infections. They can also be used to measure the pressure of the CSF, and they can be used to give treatment, including chemotherapy and pain-relieving drugs.

what happens?

You or your parents will be asked to sign a consent form to give permission for the doctors to do the test.

The lumbar puncture is done either by a doctor or sometimes by a specialist nurse who’s had training.

You'll be asked either to sit and bend over, or to lie on your side with your knees bent up. The skin on your back is cleaned with antiseptic, which will feel cold, and you’ll be given a local anaesethetic to numb the area where the needle is put in to collect the fluid. There will then be a wait of a few minutes to give the anaesthetic time to work. You’ll be asked to lie very still, then you’ll feel some pressure or pushing as the needle is inserted between two of the bones in your back (vertebrae). The CSF is drawn out, then the needle is then removed and a dressing is put over the site.

If you’re having a lumbar puncture to give chemotherapy or a painkiller, then the drug will be given into the needle rather than the CSF being removed.

Having a lumbar puncture takes about 20 minutes. It shouldn’t be painful but you may feel uncomfortable.

afterwards

You may have a headache, and you can take painkillers for this. You’ll be asked to stay lying down for a few hours afterwards - exactly how long depends on how you feel.

The nurses will check on you for a few hours after the lumbar puncture to make sure you’re OK. The doctor or nurse will tell you when you can go, and then you should be able to carry on as normal. Your dressing can be removed the next day.