Lumbar Puncture – Spine Procedure Series

Procedure: Lumbar Puncture

Clinical Keywords: lumbar puncture, intrathecal chemotherapy, myelography/myelogram

In Plain Language:

A lumbar puncture (spinal tap) is a procedure performed by a provider where a needle is placed into the fluid-filled sac that surrounds the spinal cord and nerves in the lower back within the backbone or spine.  X-rays are used to guide the needle safely and efficiently to ensure that the fluid (cerebrospinal fluid or CSF) can be removed for getting lab tests or to ensure that medications or contrast can be administered within the fluid with minimal risk.

Medical Description:

A lumbar puncture (sometimes called a “spinal tap”) is a procedure in which a provider such as a radiologist places a needle into the subarachnoid space of the spine where cerebrospinal fluid (CSF) is located and can be done with or without image guidance (moving x-rays called fluoroscopy).

Within our backs is our spinal column made up of vertebrae and these vertebrae form a ring where the spinal cord is located surrounded by CSF.  In the lower back (lumbar region), the spinal cord ends, and only small nerve roots remain floating in the CSF.  Lumbar punctures are performed in this region because the spinal cord can be avoided when the needle is put in place.

Lumbar punctures are typically performed for:

1. Diagnostic: sampling of the CSF fluid when someone has an infection (meningitis), multiple sclerosis or other autoimmune diseases, cancer

3. Therapeutic: removal of fluid when someone has high CSF pressure (idiopathic intracranial hypertension)
4. Injection: contrast (myelography/myelogram), chemotherapy

The procedure itself involves a very small needle (similar to when getting blood drawn) and numbing of the skin while a patient is either lying on the side or on the stomach. The performing provider (radiologist) will use the x-ray/fluoroscopic machine to guide the needle through the vertebrae and into the space with the CSF.                               

(T2-weighted MRI Image)

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