What is a Lumbar Puncture (Spinal Tap)?
A lumbar puncture (also called a spinal tap) is a minimally invasive, image-guided diagnostic test that involves the removal of a small amount of cerebrospinal fluid (CSF) —the fluid that surrounds the brain and spinal cord—or an injection of medication or other substance into lumbar (or lower) region of the spinal canal.
Why is a lumbar puncture performed?
A lumbar puncture is typically performed to:
- collect a sample of cerebrospinal fluid to be analyzed in a laboratory
- measure the pressure of fluid in the spinal canal using a manometer.
- remove some cerebrospinal fluid to decrease pressure in the spinal canal
The lumbar puncture procedure helps physicians diagnose:
- bacterial, fungal and viral infections, including meningitis, encephalitis and syphilis.
- bleeding around the brain (subarachnoid hemorrhage)
- cancers involving the brain and spinal cord
- inflammatory conditions of the nervous system, including Gullain-Barre syndrome and multiple sclerosis.
What do I need to do to prepare for this exam?
Our Radiologists suggest having an MRI or CT of the brain within 3 months of the exam if you have a history of cancer or within 6 months if no history of cancer. If you have not had this exam done prior to your appointment, we can provide that exam same day prior to your appointment with a doctors order.
If you take a blood thinner like Aspirin, Warfarin, Heparin, Lovenox or Plavix, please advise upon scheduling your exam.
Please plan to be in our office for 90 minutes and have a driver.
How is a spinal tap performed?
- You will be positioned lying face down on your stomach on the examining table.
- The area of your body where the catheter is to be inserted will be sterilized and covered with a surgical drape.
- The Radiologist will numb the area with a local anesthetic. This may briefly burn or sting before the area becomes numb.
- Guided by real-time x-ray images fluoroscopy, the physician will insert the needle through the skin between two lumbar vertebrae and into the spinal canal. Once the needle is in place, you may be asked to change your position slightly while fluid pressure in the spinal canal is measured.
Depending on the reason for your lumbar puncture:
- a small amount of fluid may be withdrawn through the needle to be tested in a laboratory
- cerebrospinal fluid may be removed to relieve pressure in the spinal canal
- chemotherapy or other medication may be injected into the spinal canal as prescribed by your physician
- The needle is then removed.
- Pressure is applied to prevent any bleeding and the opening in the skin is covered with a bandage. No sutures are necessary.
What will I experience during the procedure?
- Most of the sensation is at the skin incision site. This is numbed using local anesthetic. You may feel pressure when the catheter is inserted into the spinal canal. However, you will not feel serious discomfort.
- You will be asked to remain very still during the procedure.
- You should plan to lay on your back and rest the day following your procedure.
- Some patients develop a headache after a lumbar puncture that begins several hours or up to two days after the procedure. The headache may be accompanied by nausea, vomiting and dizziness and can last from a few hours to a week or more. You also may feel pain and tenderness in your lower back, which may radiate down your legs.
- A pain-relieving medication such as acetaminophen can help reduce headache or back pain following the procedure. If your headache is severe, you should contact your doctor.