A lumbar puncture (spinal tap) is a procedure performed on your lower back in the lumbar area. The procedure involves inserting a needle into your lower back between two vertebrae in order to retrieve a sample of cerebrospinal fluid. Cerebrospinal fluid serves as a protective barrier that encases your brain and spinal cord.

A lumbar puncture can help diagnose serious infections and other conditions, which include:

• Meningitis
• Guillain-Barre Syndrome 
• Multiple Sclerosis
• Cancers of the brain or spinal cord

A lumbar puncture can also be used to inject anesthetic medications or chemotherapy medications into the cerebrospinal fluid.

What Does a Lumbar Puncture Do? What is the goal of a LP?

A lumbar puncture can serve many purposes. A doctor might recommend an LP for issues including:

• Bleeding in the brain
• Meningitis or encephalitis
• Leukemia or other cancers
• Multiple sclerosis
• Myelitis
• Dementia
• Administering anesthesia, such as an epidural
• Injecting dye for an x-ray (myelogram)
• Injecting cancer medications
• Injecting muscle relaxers
• Relieving intracranial head pressure

The purpose of lumbar punctures is to help doctors diagnose any underlying conditions that are causing symptoms or to provide pain relief from different conditions. 

How Should Patients Prepare for a Lumbar Puncture Test?

There are a few steps to take in order to prepare for your LP. It is important that you follow your health care provider’s instructions. Some general steps include:

• You may be asked to do a blood test to make sure your blood is clotting appropriately
• Provide a list of medications (including antibiotics) and supplements
• Stop taking blood thinner medications (aspirin and warfarin)
• Let your doctor know if you are allergic to povidone-iodine (antiseptic) or procaine (anesthetic)
• Let your doctor know if there is a possibility of being pregnant
• On the day of the procedure, do not eat or drink 3 hours prior to the procedure
• Make travel plans to have someone drive you home after the procedure, as it is not recommended to drive for at least 24 hours after the procedure (this must be a friend or family member and not a cab or public transportation)

What to Expect During a Lumbar Puncture?

A lumbar puncture (spinal tap) can be done as an outpatient procedure or in the hospital. Typically, you will be given an option of staying in your own clothes or wearing a hospital gown. To get started, a healthcare professional will have you choose to either lie on your left side in a fetal position or to be in a seated position with your arms and head on a stable surface. Once you are comfortable, the next steps of the procedure include:

• The skin where the puncture is made is cleaned with an antiseptic
• A local anesthetic is injected into the lower back to numb the area (may be a slight burning sensation
• A hollow needle is inserted between two vertebrae in your lower spine (may feel some pressure)
• The needle either draws fluid out, or injects fluid in (medication or dye)
• The needle will be withdrawn, and a bandage will be placed on the puncture site. 

Conditions Diagnosed with a Lumbar Puncture Test

There are several conditions that can be diagnosed from doing a lumbar puncture test. These conditions include:

• Meningitis
• Guillain-Barre Syndrome 
• Multiple Sclerosis
• Cancers of the brain or spinal cord
• Dementia
• Myelitis

Results & Follow-up

There are a few things a patient can expect after they finish their procedure. Typically, you will lie down for about an hour after the procedure. It is also recommended that you drink plenty of fluids after the procedure as this will reduce the likelihood of developing a headache. Additionally, it is recommended to resume activities and exercise only after 24-48 hours. You will be encouraged to rest for the remainder of the day.

Make sure to have a friend or family member to drive you home, as you will not be allowed to drive for the next 24 hours. Additionally, once you have been home, please let your healthcare provider know if you are experiencing any of the following symptoms:

• Numbness and tingling of the legs
• Drainage of blood or pain at the puncture site
• Inability to urinate
• Constant headaches

Questions you can ask your provider:

• When can I expect my results?
• Where should I have this procedure done?
• How long will the effects of the lumbar puncture last?