Cisternal puncture
Key points
- CSF collection is a procedure to obtain a specimen of cerebrospinal fluid (CSF).
- Lumbar puncture (spinal tap) is the most common means of collecting a specimen of CSF.
- You must be prepared to remain in the hospital for at least 6 to 8 hours, and you must remain flat.
- The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experience, and level of trust.
Alternative names
Spinal tap; Ventricular puncture; Lumbar puncture; CSF collection; Spinal fluid specimen
Definition
CSF collection is a procedure to obtain a specimen of cerebrospinal fluid (CSF). CSF is the fluid that bathes, cushions, and protects the brain and spinal cord. It flows through the skull and spine in the subarachnoid space, which is the area inside the arachnoid membrane.
How the test is performed
Lumbar puncture (spinal tap) is the most common means of collecting a specimen of CSF. You are positioned on your side with your knees curled up to your abdomen and your chin tucked in to your chest. (Occasionally this procedure is performed with the person sitting bent forward).
The skin is scrubbed, and a local anesthetic is injected over the lower spine. The spinal needle is inserted, usually between the 3rd and 4th lumbar vertebrae.
Once the needle is properly positioned in the subarachnoid space, pressures can be measured and fluid can be collected for testing. After the sample is collected, the needle is removed, the area is cleaned, and a bandage is applied. You will be asked to remain flat, or nearly flat, for 6 to 8 hours after the test.
Lumbar puncture (with fluid collection) may also be part of other procedures, particularly a myelogram (X-ray or CT scan after dye has been inserted into the CSF).
Alternative methods of obtaining CSF are rarely used, but may be indicated if there is a problem such as lumbar deformity or infection, which would make lumbar puncture impossible or unreliable.
Cisternal puncture involves insertion of a needle below the occipital bone (back of the skull). It can be hazardous because the needle is inserted close to the brain stem.
Ventricular puncture is even more rare, but may be indicated when sampling of CSF is necessary in people with possible impending brain herniation. It is usually performed in the operating room. A hole is drilled in the skull and a needle is inserted directly into the lateral ventricle of the brain.
How to prepare for the test
You must sign a consent form. You must be prepared to remain in the hospital for at least 6 to 8 hours, and you must remain flat.
Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experience, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:
Written and revised by
David Cohen, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
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