Hi, just got this off the internet:

Here you go:
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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.


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Hope this explains it.

Take care,
Melody