I dunno, csf samples (and corresponding data) can be quite valuable. For example, I know someone who had a spinal cyst removed and learned that to this day the

I dunno, csf samples (and corresponding data) can be quite valuable. For example, I know someone who had a spinal cyst removed and learned that to this day they do not understand if the fluid is coming from inside or outside the cyst. We lack basic mechanistic information about these issues because there is so little data (then again the papers I looked at that did have such data only checked averages and otherwise weak/incorrect analysis).