A lumbar puncture, or spinal tap, is a procedure used to obtain a sample of cerebrospinal fluid (CSF) for testing. CSF acts like a cushion, protecting your brain and spine from injury. The fluid is normally clear. The test is also used to measure pressure in the spinal fluid.
A lumbar puncture is also used to administer some chemotherapy drugs. The medications are injected directly through the lumbar puncture and into the cerebrospinal fluid where they flow freely to the brain and spinal cord.
Before the Test
Tell your doctor or nurse practitioner if you are taking any type of prescription or over-the-counter medications, vitamins, or herbal supplements that may affect your blood’s ability to clot. This would include aspirin, warfarin/Coumadin®, Lovenox®, heparin, Plavix®, ibuprofen/Advil®, and naproxen/Aleve®. Your doctor may want you to stop these medications a few days before your procedure.
How is the Test Done?
- You will need to lie on your side, with your knees pulled up toward your chest, and your chin tucked downward. Sometimes, the test is done while you are sitting up and bending forward.
- After your back is cleaned, a local numbing medicine (anesthetic) is injected.
- When the area is numb, a small spinal needle is inserted.
- Once the needle is properly positioned, spinal fluid pressure is measured, and fluid is collected.
- The needle is removed, the area is cleaned, and a bandage is placed over the needle site.
Occasionally, special x-rays are used to help guide the needle into the proper position. This is called fluoroscopy.
How Will I Feel During the Test?
The position may be a little uncomfortable, but it is extremely important that you remain in this position and stay very still. If you move, you may cause the needle to move, which could possibly injure the spinal cord. The anesthetic is likely to sting or burn when first injected. Once the area is numb, you will only feel a hard pressure sensation when the needle is inserted. There is usually some brief pain when the needle goes through the tissue surrounding the spinal cord but it should stop in a few seconds. Overall, the discomfort is minimal to moderate. The actual pressure measurements and fluid collection only take a few minutes.
After the Test
Your doctor may ask you to increase your fluid intake and to lie flat for 2-4 hours after the procedure to help prevent a spinal headache. (A spinal headache gets worse when you sit up or move around but lessens or goes away when you lay down.) You can remove the bandage over the insertion site after 24 hours.
Are There Any Risks?
Spinal headaches may occur in some people up to 12 hours after the procedure. Lying flat and drinking extra fluids may help prevent or lessen these headaches. Please call us if your headache lasts more than 1 day. Less common risks include allergic reaction (to the anesthetic), bleeding, damage to the spinal cord (particularly if you move during the procedure), and infection.
For the quickest recovery, and to help avoid a spinal headache:
- Lay down flat for the rest of the day and have someone else do the household chores
- Drinks lots of fluids for the rest of the day (unless you are on a fluid restricted diet)
- Avoid heavy physical activity for a few days
- Take acetaminophen (Tylenol®) for back pain or headache
When to Call Us
Call your doctor if you have:
- a spinal headache that lasts longer than 1 day
- a fever over 99°F
drainage from the needle site or if the skin around the needle site feels spongy or swollen