Lumbar puncture Werohanga tangai
In a lumbar puncture, a hollow needle is inserted between the bones of your lower back into the fluid around the lower part of your spinal cord. A sample of fluid is taken and sent to the laboratory for testing. This fluid is called cerebrospinal fluid.
When you would have a lumbar puncture
Lumbar punctures are done to:
- look for or exclude conditions affecting your spine, brain or nervous system
- inject medicines, such as antibiotics, chemotherapy or pain medication, into your cerebrospinal fluid
- measure the pressure in your cerebrospinal fluid
- drain the cerebrospinal fluid if the pressure is too high.
Your lumbar puncture will be carried out by a specialist. They will explain what happens and why you need one. It will take around 20 minutes.
Injecting chemotherapy into the cerebrospinal fluid is known as intrathecal chemotherapy. This can be done for people whose cancer has spread into their cerebrospinal fluid. It can also be done to help stop this from happening.
You will need to lie flat for some time after your lumbar puncture. You may want to go to the toilet beforehand.
Having a lumbar puncture
During the procedure, you will be asked to either:
- lie on one side with your knees drawn up towards your chest
- sit up bent over a table, and supported by pillows.
This helps your back curve as much as possible, so the bones of your spine (your vertebrae) are widely separated.
The skin over your lower spine will be cleaned, and a local anaesthetic will be injected to numb the area.
The doctor will insert a hollow needle between 2 of your vertebrae into your spinal canal. This is the space in the middle of your spine, where your nerves are.
You will need to stay as still as possible. You may feel some pressure as the needle is put in. The doctor will take samples of your cerebrospinal fluid or inject chemotherapy drugs if that is what you need.
They will then take the needle out and put a small dressing over the site.
After a lumbar puncture
A lumbar puncture is not usually painful. But some people find it uncomfortable.
You might have a headache for a few hours after, so you will need to lie flat for one hour. You can turn from side to side, but sitting up might make the headache worse. The headache can last up to 3 days.
Tell the doctor or nurse if you have a headache — they can give you some pain medicine relief like paracetamol. They will also check your blood pressure and pulse. Ask them when it is okay to sit up. After resting and feeling better, you can go back to your normal activities.
Sometimes people need more than one lumbar puncture. If you are having intrathecal chemotherapy, you may need several doses. You will need to have a lumbar puncture each time.
Results for a lumbar puncture
The time it takes to get results from a lumbar puncture can vary depending on what tests are being done on the fluid collected.
Risks of a lumbar puncture
The most frequent complication is a headache.
You may bleed slightly from the lumbar puncture site, but this is usually minor.
There is a small risk that the lumbar puncture site will become infected.
Contact the hospital where you had your lumbar puncture if you:
- have a headache that will not go away
- have a fever (temperature over 38°C)
- have any other concerns related to your lumbar puncture.
Informed consent
Healthcare services may be provided to you only if you make an informed choice and give informed consent to it. This forms part of your rights (Rights 5, 6 and 7) under the Code of Health and Disability Services Consumer Rights (the Code).
The Code and Your Rights/Ōu Mōtika — Health & Disability Commissioner
The 3 rights that together allow for informed consent are:
- Right 5 — the right to effective communication
- Right 6 — the right to be informed
- Right 7 — the right to choice and consent.
This means you must be told about the service being suggested, including any risks or possible complications. You must have the chance to ask as many questions as you need to understand the information you are given.
You also have the right to have someone with you to help you. But the decision to say 'yes' or 'no' must be yours (unless you are unable to make that decision due to illness or other impairment, or sometimes in an emergency).
You also have the right to be given the information in a language you fully understand. You can ask for an interpreter if you need one.