the lumbar puncture to test spinal fluid is not too bad. I have had one done by my neurologist, and it was painless. The last one, also done by a doctor, was a machine guided puncture...that one was more painful, but nothing worse than a needle type pain. It also failed to seal, so I had to return to the hospital to have a "blood patch"...in which the same doctor injected blood back into the original site, to stop the leaking, and to stop the headache. And that went very well.