A lumbar puncture (spinal tap) test drains a small sample of cerebral spinal fluid from the lower spine. A needle is inserted between the vertebrae (backbones) in the lower back and into the space containing the spinal fluid.
What is it?
- a procedure to remove a small sample of cerebral spinal fluid from the lower spine
- this fluid surrounds and cushions the brain and spinal cord
How long does it take?
- about 20 to 30 minutes
- there is a possible 2-hour recovery period after the test, which will take place here at the Neurology Clinic
Why is the lumbar puncture test performed?
- to determine the spinal fluid pressure
- to obtain a specimen for testing (for either infection or bleeding)
- to relieve pressure around the brain by removing fluid
- to inject medications around the spinal cord
Does it hurt?
- you may experience pressure when the needle is inserted. You may also feel some fleeing leg pain while the needle is positioned because it may briefly touch a floating nerve ending.
Where is it conducted?
- the Neurology Clinic Treatment Room
- 2nd floor Carver Pavilion
How many lumbar puncture tests are conducted each year?
- several hundred
What should you do to prepare for the test?
- eat normal meals
- if you are an outpatient, please bring a relative or friend who can drive you home
- continue taking prescribed medications unless your doctor gives other instructions
How is it performed?
- you will lie on your side with your knees drawn up toward your chin as far as possible
- the doctor will cleanse the skin over your spinal column with iodine
- an injection of local anesthetic may be given at the puncture site
- a needle is inserted into your spinal fluid space
- a long, thin tube called a manometer is attached to the needle to measure the fluid's pressure
- spinal fluid is collected into specimen tubes for laboratory testing
Frequently asked questions
Q: What if I'm unable to flex my back and legs?
A: The test can be done without bending or while sitting.
Q: Is the entire needle put into my back?
A: No, but the needle must be long enough to pass through the muscles of the lower back.
Q: Can I be paralyzed if the needle hits the spinal cord?
A: No, there is no need to worry about spinal cord damage. The needle is inserted well below the spinal cord.
After the test
- you will be asked to lie on your stomach for about 30 minutes
- after that, you will be asked to lie on your back or side for 15 to 90 minutes
- your nursed will check the puncture site periodically for swelling or leakage of spinal fluid. They will also ask you to wiggle your toes and move your legs.
- report any of the following symptoms to the doctor or nurse:
- numbness or pain in your lower back and legs
- problems with urination
- you may return to your hospital room or home, unless given other instructions from the doctor
- if you are being driven home, you should lie down in the vehicle, if possible
- you will learn the test results either from the doctor before you leave, or from a copy of the letter sent to your personal physician
Instructions to follow at home
- drink 8 to 12 glasses of fluid (no alcohol) in the next 12 hours, unless your doctor indicates otherwise
- remain quiet for the next 24 hours
- avoid any strenuous physical activity for 48 hours
- if you develope a headache, lie flat for the next 12 to 24 hours or until the headache goes away. Remember to drink plenty of fluids.
- if your headache persists, call your home physician or the physician at the hospital who performed the lumbar puncture test.
Neurology clinic hours
- during regular hours: call the nurses' station at (319) 356-2957
- after hours and on weekends: neurology resident on-call at (319) 356-1616
University of Iowa Department of Neurology