Lumbar puncture is used to diagnose infections and disorders of the central nervous system.
What is a lumbar puncture?
A lumbar puncture is a common medical procedure used to diagnose infections and various disorders of the central nervous system. It can also be used to measure, or sometimes relieve, pressure around the brain and spinal cord.
Called spinal tap in popular language, the procedure involves collecting a sample of cerebrospinal fluid (CSF) by inserting a thin, hollow needle into the lower part of the spine.
“The CSF is a clear, protective fluid surrounding the brain and spinal cord. It can be analysed for problems such as infection, bleeding or inflammation,” says the Department of Neurology, National Neuroscience Institute (NNI), a member of the SingHealth group.
What conditions can be diagnosed with a lumbar puncture?
A lumbar puncture can be used to inject medications in the cerebrospinal fluid, but most commonly it is used to collect a sample to detect or rule out conditions affecting the central nervous system, such as:
How is lumbar puncture performed?
Lumbar puncture is performed under local anaesthesia. This means the patient stays awake throughout the procedure but the region is numbed to any pain through injection of an anesthetic agent.
The patient’s lower back is first disinfected with an antiseptic solution. The patient can be asked to lie on one side in a curled up position or to sit down with arms and head resting on a table.
Once the anaesthetic has taken effect, a hollow needle is inserted through a small puncture site in the lower back. As the needle passes through the spinal membrane into the spinal canal, some pressure or discomfort can be felt momentarily.
Doctors can then measure the pressure of the cerebrospinal fluid, inject medication or most commonly, collect a CSF sample. The puncture site is sterilised and cleaned.
The procedure takes about 30 minutes.
Risks of lumbar puncture
The procedure is generally safe, but some people may experience complications such as:
After a lumbar puncture
You should see a doctor if the spinal headache and back pain worsen or if fever develops.
Ref: R14