Natalizumab (Tysabri) is a treatment for people with relapsing forms of MS. It makes flares happen less often and keeps physical disabilities from getting worse quickly.
Tysabri works in a different way from other multiple sclerosis drugs. It keeps the white blood cells of the immune system from entering the brain and spinal cord, which doctors think plays an important role in the damaging effects of MS.
The results of the procedure can help doctors see whether your body’s immune system is attacking itself, which is what happens in multiple sclerosis. If you have the condition, your CSF (spinal fluid) will have higher amounts of certain proteins.
If someone’s CSF doesn’t have these proteins, though, they might still have multiple sclerosis -- 5% to 10% of people with the condition never show signs in their spinal fluid.
Also, these signs can show up in a number of other diseases, too. So a spinal tap by itself can't confirm or rule out a diagnosis of multiple sclerosis. It must be part of the total picture of testing for the disease.
How Do I Prepare for a Spinal Tap?
You don’t have to do anything to get ready, unless your doctor gives you special instructions.
In most cases, you’ll need to stop taking any blood thinner medicines, including aspirin, for a few days beforehand. And if you're allergic to latex or any medications, tell your doctor.
What Happens During a Spinal Tap?
To start, you’ll lie on your side with your knees drawn as close to your chest as possible. Or you'll sit with your arms and head resting on a table.
After the skin around your lower back is cleansed and covered, you’ll get medicine to numb that part of your body. Your doctor will put a long, thin hollow needle in your low back between two bones in your lower spine and into the space filled with CSF. He’ll take 1-2 tablespoons of fluid and remove the needle. The procedure doesn’t touch your spinal cord.
What Happens Afterward?
You’ll need to lie on your back or stomach for a few hours. You also may need to give a sample of your blood for testing, too.
Avoid intense exercise for a day or so after the procedure.