How do I prepare for a lumbar puncture (spinal tap)?
- Maintain your regular eating schedule. There are no dietary or fluid restrictions before the test.
- Ask your doctor for specific guidelines about discontinuing , aspirin products, clopidogrel (Plavix®) or anticoagulant medications before the procedure.
- Tell your doctor if you are allergic to povidone-iodine (Betadine®) or procain (Novocain®).
- Please make arrangements for transportation, as you should not drive immediately after the test.
What happens during the lumbar puncture (spinal tap)?
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 sit with your arms and head resting on a table.
After cleaning your skin with an antiseptic, 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 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 has been removed. The area will be cleaned with an antiseptic and covered with a bandage.
You will lie on your back or stomach for about an hour.
A blood sample will be taken from a vein in your arm and tested, along with the spinal fluid, in the laboratory. NOTE: if the procedure was done to inject medication, a blood sample may not be taken.
Are there any risks or complications from a lumbar puncture (spinal tap)?
- Approximately 10% to 20% of people develop a spinal headache (one that worsens when sitting or standing).
- The risk of infection/epidural bleed is extremely low.
- Occasionally a small blood vessel is pierced, causing bloody discharge. No treatment is needed.
- The procedure is usually not painful, but momentary twinges of pain may be felt if the needle brushes against nervous tissue.