Spinal Tap (Lumbar Puncture)

What is a spinal tap?

A spinal tap, also known as a lumbar puncture, is a procedure where a needle is inserted between lumbar bones to remove cerebrospinal fluid (CSF) for analysis. This laboratory test helps diagnose conditions such as infectious diseases, multiple sclerosis and bacterial meningitis. It may also be used to detect abnormal levels of white blood cells in the spinal fluid, which can indicate infection or inflammation. Additionally, a spinal tap may be performed to inject dye for X-ray tests, administer medications or relieve pressure in the head.

Spinal tap risk factors

Since a spinal tap involves the brain and spinal cord, it’s important to know the possible risk factors. These may include:

• Short-term numbness in the lower body
• Risk of infection due to the needle insertion
• Headaches caused by cerebrospinal fluid leaking
• Back pain
• Bleeding near the puncture site

Discuss any concerns with your doctor before the procedure. 

How to prepare for a spinal tap

While preparation is minimal, it’s important to follow these guidelines:

• Drink plenty of fluids before the procedure, but do not eat or drink three hours beforehand.
• Let your doctor know if you feel unwell or have a fever, as your spinal tap may need to be rescheduled.
• Bring someone with you on the day of the procedure since you will not be able to drive for 24 hours.

Your doctor will provide instructions regarding any necessary blood tests or medications you are taking. 

What to expect during a spinal tap

During the procedure, your doctor will have you lie on your side and may ask you to bring your knees toward your chest. After sterilizing the area, you will receive local anesthesia to numb the site. A needle is inserted between two vertebrae into the spinal canal to collect spinal fluid for testing. While the procedure is not typically painful, you may feel pressure, discomfort or get a headache. Once the sample is collected, the site is covered with a bandage.

Spinal tap aftercare and side effects

After your spinal tap, follow these aftercare steps:

• Avoid strenuous activity for at least 24 to 48 hours.
• Drink around 2 quarts of fluids after your spinal tap (as well as the next day) to aid recovery.
• Contact your doctor immediately if you experience a fever, persistent headache or unusual fluid leakage from the puncture site.

A CSF test can provide valuable insight into neurological and infectious conditions, helping guide further diagnosis and treatment.