What is a lumbar puncture (spinal tap)?

A lumbar puncture, also known as a spinal tap, is a procedure to remove a small amount of cerebrospinal fluid (CSF) from around the spinal cord. The CSF is tested for infections and other conditions of the brain and spinal cord. A lumbar puncture is also used to inject medications and to measure and relieve pressure around the brain and spinal cord.

CSF is a clear fluid that surrounds the brain and spinal cord. It acts like a cushion to protect the brain and spinal cord. Your provider will evaluate CSF test results to diagnose many types of brain and spinal cord conditions, including meningitis and multiple sclerosis. Lumbar puncture can also be used for the injection of medications into the spinal cord, including chemotherapy and spinal anesthesia.

A lumbar puncture is only one method used to diagnose or treat a variety of diseases, disorders and conditions of the brain and spinal cord. Discuss all of your options with your provider to understand which options are right for you.

Why is a lumbar puncture (spinal tap) performed? 

Your provider may recommend a lumbar puncture to diagnose or treat many types of brain and spinal cord conditions. Conditions diagnosed using a lumbar puncture include:

  • Cancer of the brain or spinal cord
  • Encephalitis, inflammation and swelling of the brain due to a viral infection or other causes
  • Guillain-Barré syndrome, an autoimmune nerve disorder
  • Headaches that are not diagnosed by less invasive tests
  • Meningitis, infection or inflammation of the sac around the brain and spinal cord
  • Multiple sclerosis, a disease that affects the brain and spinal cord causing weakness, lack of coordination, balance difficulties, and other problems
  • Pressure or bleeding within the spinal column
  • Reye’s syndrome, an illness involving brain and liver damage that is linked to giving aspirin to children
  • Transverse myelitis, a neurological disorder causing inflammation of the spinal cord

A lumbar puncture is also used to:

  • Inject contrast to take an X-ray test including myelogram
  • Inject medications into the spinal cord including chemotherapy for cancer, spinal anesthesia for surgery, and muscle relaxants for severe muscle spasms
  • Measure or relieve pressure in the brain and spinal cord for conditions including hydrocephalus 

Who performs a lumbar puncture (spinal tap)?

A doctor, nurse practitioner (NP), nurse anesthesiologist, or physician assistant (PA) performs a lumbar puncture. The following types of doctors perform lumbar puncture:

  • Neurologists specialize in caring for people with diseases and conditions of the brain and nervous system, including the spinal cord, nerves, muscles, and related blood vessels.
  • Emergency medicine doctors and pediatric emergency medicine doctors specialize in emergency care of people with serious and life-threatening illnesses and injuries. Pediatric emergency medicine doctors further specialize in caring for infants, children and adolescents.
  • Anesthesiologists specialize in relieving pain and providing total medical care for patients before, during and after surgery.

How is a lumbar puncture (spinal tap) performed?

Your lumbar puncture will be performed in a hospital or clinic. It generally includes these steps:

  1. You will remove your clothing and dress in a patient gown.
  2. You will lie on your side on the examination table with your knees pulled up to your chest. As an alternative, you may sit on the edge of an examination table with your head and arms draped over a table in front of you. These positions allow the best access to your spine. 
  3. Your provider will clean a small area on your lower back and place sterile drapes on your back to help maintain a sterile procedure. 
  4. Your provider will inject a small amount of numbing medication under the skin.
  5. When the skin is numb, your provider will insert a very thin needle into your spinal canal and allow about a tablespoon of cerebrospinal fluid (CSF) to drip out of the needle into test tubes for testing. You must remain very still during this process.
  6. Your provider may attach a syringe of medication to the needle in your back to inject medication.
  7. Your provider may attach a device to the needle to measure pressure around the brain and spinal cord.  
  8. Your provider will remove the needle and clean and bandage the area.
  9. Your provider will send the CSF to the laboratory for testing.
  10. You will need to lie flat for about an hour to prevent a headache.