Spinal tap

What is it for?

Using cerebrospinal fluid, we can measure pressure and take samples to perform different tests.

Thanks to these tests, several diseases can be diagnosed, such as neurological disorders and infections that affect the brain or bone marrow.

How does it work?

Spinal taps, or lumbar punctures, involve taking a sample of cerebrospinal fluid through the puncture with a needle in the lumbar area.

It is usually done with patients in the foetal position: lying on their sides with legs flexed so the knees touch the chest. Sometimes, the puncture is done with the person sitting and leaning forward.

Once the patient is in place, the area where the puncture is to be done is cleansed and disinfected. After administering anaesthesia, the puncture is performed between the two lumbar vertebrae with a spinal needle.

After this, we measure the pressure of the cerebrospinal fluid and take the sample, which will be from 1 to 10 ml.

The needle is then removed, the puncture zone cleaned and a bandage placed over the puncture area. Sometimes patients need to lie down for a while.

Risks

• Discomfort during the examination
• Headache that can last hours or days
• Bleeding in the spinal canal or around the brain
• Allergic reaction to anaesthesia
• Infection from the needle
• In people who have brain tumours, it can cause brain damage
• If the person moves, the needle can cause damage to the nerves of the spinal cord

Alternatives

Spinal taps are the least aggressive way to get a sample of cerebrospinal fluid. Study of this liquid is essential to detect certain diseases that affect the brain and the spinal cord.