Anything invasive has a risk of causing damage to the body, but having gone through a spinal tap before it is safe to say that the risk of damage is quite low. They puncture the lumbar with a tiny instrument quite low on the spine so they dont run the risk of damaging anything major. The worst part of the spinal tap is the recovery and the headaches which last about 4-5 days. I don't usually drink coffe, but coffe really helped to aleviate the migranes. I was fine and up to my usual self on the 5-6th day after. Good Luck with everything!