What is a lumbar puncture?
A lumbar puncture, also called a spinal tap, is a procedure in which the fluid surrounding the spinal cord (called the cerebrospinal fluid or CSF) is withdrawn through a needle and examined in a laboratory.
This procedure may be performed to:
- Measure the pressure around the brain and spinal cord
- Relieve pressure in the head
- Give spinal anesthesia
- Inject dye for an X-ray diagnostic test
- Inject medications
There are seven cervical vertebrae in the neck, 12 thoracic vertebrae in the torso and 5 lumbar vertebrae in the lower back. The needle used in a lumbar puncture is usually inserted between the lumbar vertebrae.
The cerebrospinal fluid (CSF) circulates in the subarachnoid space of the spinal canal. It has many vital functions, including protecting the brain and spinal cord from injury. The CSF contains glucose (sugar), proteins and other substances that are also found in the blood. Testing the CSF can help in the diagnosis of disorders of the central nervous system that may involve the brain, spinal cord or their coverings (meninges).
Who performs the test?
The lumbar puncture procedure is performed by a physician trained in the use
of X-ray equipment, called flouroscopic equipment, which allows the doctor to
view the needle as it is placed into the subarachnoid space.
Notify your physician
Inform your physician of any medications you are currently taking, including
non-prescription drugs. Also tell your physician if you are allergic to any medications.
NOTE: Do not discontinue any medication without consulting with your primary
physician and/or physician requesting this study.
If you have any of the following conditions, please notify your physician:
- Allergies to any drugs or foods
- Are pregnant or think you may be
Before the test
A blood test or other laboratory tests may be ordered by your doctor prior to
the test. Please follow these guidelines before the test:
- Do NOT take dipyridamole (Persantine), clopidogrel (Plavix) or warfarin
(Coumadin) within 72 hours prior to the test. These medications are often
referred to as blood thinning pills.
- Do NOT take aspirin or any products containing aspirin.
- DO take your other medications as determined by your physician, especially
any medications for high blood pressure.
- Ask your doctor for specific guidelines regarding alcohol use before the
test. Generally, you should not consume any alcohol for at least 24 hours prior to the test.
If you have diabetes
- Take your usual dose of insulin and eat a light breakfast before 8:00 a.m.
- When you arrive for your test, please be sure to remind the physician that you have diabetes.
Eating and drinking
You may eat a light breakfast the morning of the test.
On the day of your test
- Please make arrangements for transportation, as you should not drive immediately after the test.
- Please do not bring valuables such as jewelry or credit cards.
You will meet with the radiologist in the Department of Radiology, Desk Hb6. In addition to providing verbal consent, you will discuss:
- Steps of the procedure and any questions you may have regarding the procedure.
- Risks and benefits anticipated in your case.
During the test
- The radiologist and technologist will be in the room with you.
- Pre-medication, although rarely needed, may make you feel drowsy and relaxed.
- You will wear a hospital gown during the examination.
- You will either:
- Lie on your side with your knees drawn as close to your chest as possible and your chin
toward your chest; or
- Lie on your stomach with a small pillow beneath your lower abdomen.
- Your back will be cleaned with an antiseptic and sterile cloths (called drapes) will be placed around the area.
- A local anesthetic (pain-relieving medication) will be injected into the
area on your back. You may feel a slight burning sensation.
- When the area is numb, a hollow needle is inserted in the lower back
between the two lumbar vertebrae. This sometimes causes pressure.
- The spinal canal is penetrated, and fluid is collected or medication is
injected. The spinal cord is not touched by the needle during the test.
- You may feel some discomfort or have a minor headache.
- The needle is removed after the medication has been injected or fluid is
removed. The area will be cleaned with an antiseptic and covered with a small bandage.
- You will lie on your back or stomach for about an hour.
- A blood sample may be taken from a vein in your arm and tested, along with the spinal fluid, in the laboratory.
After the test
You will be monitored in Radiology Recovery for a few hours. At that time, the Radiology nurse will discuss post-procedure instructions with you. You will
be provided with a written form of these instructions -- please follow these at home.
The results of your study will be discussed with your referring physician within 24 hours.
Please call the Division of Radiology at 216.444.6640 if you have any questions.
For the first 24 hours after the test
- Remain flat on your back as much as possible.
- Drink at least 2 1/2 quarts of fluid.
- Notify the Division of Radiology if you experience any drainage from the puncture site, or headache.
National Institute of Neurological Disorders and Stroke. Neurological Diagnostic Tests and Procedures.
www.ninds.nih.gov Accessed 3/15/2011
American Academy of Orthopaedic Surgeons. Spinal Injections.
orthoinfo.aaos.org Accessed 3/15/2011
© Copyright 1995-2011 The Cleveland Clinic Foundation. All rights reserved.
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 8/20/2011...9252