Lumbar Puncture (Spinal Tap)

June 12, 2024 

This page was reviewed under our medical and editorial policy by Leslie Popplewell, M.D., hematologist and medical director of Hematology and Blood and Bone Marrow Transplant, City of Hope^® Cancer Center Atlanta

A lumbar puncture, also known as a spinal tap, may be ordered for a patient if a doctor is concerned that particular conditions have developed, or certain diseases have spread. This procedure helps doctors monitor possible cancer progression, deliver medications and diagnose health issues that affect the fluid of the brain and spinal cord.

What Is a Spinal Tap?

A spinal tap removes a sample of the fluid that flows through the brain and spinal cord, known as cerebrospinal fluid (CSF). A small amount of this fluid is extracted and then examined in a laboratory to detect changes that may signal a health problem, such as disease, injury or infection.

What Does a Lumbar Puncture Test for?

People may undergo a lumbar puncture test for a variety of reasons, including if their medical care team needs to check for:

• The spread of certain cancer cells into the spinal fluid, such as non-Hodgkin lymphoma, acute myeloid leukemia or acute lymphocytic leukemia cells
• The extent of certain spinal cord and brain tumors, such as ependymoma
• Conditions such as multiple sclerosis or other autoimmune disorders
• Infections of the brain or spinal cord, such as meningitis or encephalitis
• Brain hemorrhage (bleeding) due to injury or other causes
• Dementia, such as Alzheimer’s disease

How to Prepare for a Spinal Tap

Anyone undergoing a spinal tap procedure should be accompanied by someone who may drive him or her home (or accompany the patient in a cab) from the hospital or clinic.

Before a spinal tap, patients should also talk with their doctor about the following.

Medications and supplements: Blood thinners such as Coumadin^® (warfarin), aspirin or ibuprofen may need to be temporarily discontinued until after the spinal tap. Patients should be sure to mention any other prescription medications they take, such as antibiotics or non-steroidal anti-inflammatory drugs (NSAIDs), as well as any herbal supplements.

Eating and drinking before the procedure: The doctor may say it is fine to eat and drink as usual, or patients may be told not to have anything to eat or drink after midnight on the day of the procedure.

Pregnancy: Patients who are pregnant may be advised to reschedule because the guided X-ray images obtained during a spinal tap may pose a radiation risk to the fetus.

What to wear: Sometimes patients are given a hospital gown to wear, and sometimes the procedure is performed while they are wearing their regular clothing. That’s why it is advisable to wear loose, comfortable clothes. Leave watches, jewelry and other accessories at home.

The type of anesthetic or sedation: The level of sedation varies for spinal tap procedures. All assist with pain management. Most patients receive a local anesthetic, which is an injection of pain-relieving medicine to numb the lower spine area. Some also receive moderate (conscious) sedation, medications that make the person sleepy but still able to respond when touched or addressed. With moderate sedation, patients are also able to breathe on their own. Some patients may require or request general anesthesia instead. These are medications that cause a deep sleep and require a tube to help the patient breathe. Patients should let their doctor know about any pain management preferences so that the risks and benefits of each may be discussed.

Allergies: If the patient has any allergies, especially to local or general anesthesia or conscious sedation medications, it is important to mention this as well.

Before the procedure: The patient must sign a consent form agreeing to the procedure. People who are receiving conscious sedation medication or general anesthesia receive this form just before the spinal tap begins.

What to expect after the procedure: Patients should review the general aftercare instructions, including the level of pain to expect, possible side effects, length of the hospital stay, how long to remain still (stationary), when it’s OK to resume normal activities and any problems afterward that should be reported to the doctor.

Lumbar Puncture Procedure

Here are the steps of a lumbar puncture procedure:

• The patient is asked to sit or lie down on his or her side on an examination table, and a nurse may connect heart rate, breathing and blood pressure monitors to track these vital signs throughout the procedure.
• If children are undergoing the procedure, a medical technician or nurse may hold them in place for the next steps of the procedure to help them stay still.
• The lower back (lumbar spine) where the thin spinal tap needle will be inserted is cleaned, sterilized and covered with a surgical drape.
• A local anesthetic is injected into the lower back area to numb the area.
• Fluoroscopy (guided X-ray images) may be used to help the doctor as he or she inserts the needle into the spinal canal between two bones (vertebrae) in the lower spine.
• A small quantity of cerebrospinal fluid is drawn up through the needle.
• The needle is removed, and pressure is applied to the area to stop the bleeding.
• The area is covered with a bandage or dressing.
• The patient lies on his or her side or back for at least an hour, sometimes longer, after the procedure.

For those receiving general anesthesia, these steps will be similar, except the patient won’t receive local anesthesia and his or her vital signs will be monitored by an anesthesiologist throughout the procedure.

Is a Spinal Tap Painful?

A spinal tap may cause a little discomfort when the needle is inserted, but it is not generally considered painful because local anesthesia is commonly used. Some people feel a pinch when the doctor puts the needle in, but this feeling typically lasts just seconds.

How Long Does a Lumbar Puncture Take?

The procedure should last no more than 30 minutes. Afterward, patients may expect to spend at least 30-60 minutes in the hospital or clinic resting on their back, depending on how much cerebrospinal fluid was removed. This allows the doctor to check the puncture site and ensure there is no bleeding in the spinal canal where fluid was removed.

Spinal Tap Recovery

Recovery from a spinal tap begins in the hospital, where the patient is encouraged to drink lots of water to help replenish the cerebrospinal fluid and prevent a headache. Lying flat on the back after the procedure also helps prevent a headache.

After a few hours, the patient is sent home with an accompanying adult. Patients should not drive or operate heavy machinery for about a day. The bandage or dressing may be removed after about 24 hours.

Some side effects that patients may experience in the hours and days following a spinal tap include:

• Headache, which may last a few hours to a week or more. It may be managed by staying well hydrated and taking over-the-counter pain medication such as acetaminophen.
• Nausea
• Vomiting
• Dizziness
• Lower back pain or tenderness
• Pain or tingling sensations down the legs
• Bleeding
• Infection

Patients should contact their doctor immediately if they have the following:

• Fever
• Vomiting
• Severe headache
• Leg pain or tingling
• Heavy bleeding at the puncture site

Spinal Tap Results

The lab test used to analyze a lumbar puncture sample is called a cerebrospinal fluid (CSF) analysis. A CSF analysis checks the fluid’s appearance, pressure and levels of total protein, gamma globulin protein, glucose (sugar) and blood cells in the sample.

The time it takes to get the results of the CSF analysis varies — it may take up to a few weeks or more. Patients are encouraged to reach out to their cancer care team with any questions or concerns while they wait.

When the results come in, the care team will help patients understand their results and recommend any other testing that may be needed. For example, high total protein levels may point to such health issues as tumors, diabetes, or inflammatory or infectious diseases. Cancer cells in the CSF may indicate leukemia, lymphoma or brain tumors.

Interpreting these results includes scheduling a time to consult with the doctor, who will recommend any necessary follow-up care and treatment. Treatment plans are customized to each patient’s unique health conditions.