Risks

Although infrequent, several complications can occur as a result of a spinal tap.

• Headache
  
  
  • About 5-30% of people who have a spinal tap get what is commonly referred to as post-lumbar puncture headache.
    
    
  • Your headache may start up to 48 hours after the procedure and usually lasts for 2 days or less.
    
    
  • The headache typically worsens when you are in an upright position and lessens when you lie flat.
    
    
  • The cause of the headache is leakage of the spinal fluid from around the puncture site.
    
    
  • Younger people and males have an increased risk of headaches after lumbar puncture compared with older people and females.
    
    
  • You reduce your chance of getting one of these headaches by drinking plenty of fluids, especially caffeine products such as tea, coffee, and cola.
    
    
  • Occasionally, a blood patch is needed. An anesthesiologist or pain management specialist injects a small amount of your own blood at the site where the spinal tap was performed. You usually experience relief within 30 minutes after this procedure.
  
  
• Herniation
  
  
  • A herniation can occur if an abscess (pocket of infection) or increased intracranial pressure (ICP) is present during your spinal tap.
    
    
  • If the pressure in your brain is elevated when the spinal tap is performed, the flow of fluid from the brain down the cord may cause the brain to get squeezed down into the direction of the spinal cord. This is extremely rare and occurs only with elevated intracranial pressure.
    
    
  • If a person has signs and symptoms consistent with meningitis (fever, headache, and stiff neck), then the spinal tap may be performed immediately. In some people, a CT scan of the brain is performed first, however, to rule out the possibility of bleeding or other causes that may increase the pressure within the skull or around the brain.
    
    
  • If increased intracranial pressure is suspected, great caution is taken and your condition is carefully discussed before a spinal tap is performed, if it is performed at all.
  
  
• Bleeding
  
  
  • Injury to the blood vessels that surround the covering of the spinal canal may occur when the needle is being inserted. Frequently referred to as a traumatic tap, this may cause a small amount of localized bleeding.
    
    
  • Sometimes this can affect the results of the procedure, which would mean that the doctor would have to re-insert the needle into another area of the back, frequently an inch or so away from the first site. Proper numbing medicine, if needed, is injected to decrease any pain.
    
    
  • The spinal cord ends at the level of the first or second lumbar vertebrae, and the needle is usually inserted at a level between the third and fourth or the fourth and fifth lumbar vertebrae, keeping the spinal cord completely out of danger.
  
  
• Epidermoid cyst
  
  
  • Rarely, certain tissues (epidermoid) are accidentally implanted into the spinal canal when the spinal tap is performed.
    
    
  • The likelihood of an epidermoid cyst is much greater when a needle without a stylet is used, and this almost never occurs today. All spinal tap kits used today have needles with stylets.