Lumbar puncture

A lumbar puncture is a test where a needle is inserted into the lower part of your spine to remove some spinal fluid.

This test is used to look for conditions affecting your spine, brain or nervous system. It is often used to help diagnose or exclude conditions such as meningitis, subarachnoid haemorrhage and neurological conditions, eg, Gullian-Barre Syndrome and multiple sclerosis.undefined

A lumbar puncture can also be used to deliver antibiotics or chemotherapy medication directly to the cerebrospinal fluid in your spine.

How is a lumber puncture done?

No preparation is needed. You will have a small local anaesthetic injection into your skin before a needle is inserted between 2 vertebrae (back bones) into your spinal canal.

You will lie on your side, legs pulled up with your chin tucked in, or you may be seated and leaning forward. This helps open up the space between the vertebrae.

Once the needle is in the right place, a few drops of cerebrospinal fluid are collected into a sterile container and sent to the lab. If needed, the spinal pressure can also be measured. 

  • The needle is only in your back for a few minutes although the whole procedure takes 20–45 minutes.
  • You will have a small plaster over the exit point.
  • Once finished, you will need to remain lying down for another 30 minutes or so.
  • It is best to rest for several hours to reduce the risk of getting a headache.

What are the risks of a lumbar puncture?

There is little risk of any major complication due to the procedure. However, some people will experience a headache within the next 24–48 hours. This can be treated by drinking plenty of fluids and taking a painkiller such as paracetamol.

There may also be some soreness in the area the needle was inserted into.

Results 

Some results are available within an hour while others may take up to 48 hours. Your doctor will explain your results.

Learn more

Lumbar puncture factsheet KidsHealth, NZ
Lumbar puncture NHS, UK

Credits: Health Navigator Editorial Team.