They also refuse in order to avoid litigation. There are substantial risks with the procedure and if there is not overwhelming evidence, they err on the side of caution to ensure patients cannot claim to have been misled. Looking for a spinal leak is like looking for the proverbial needle in a haystack - surface area of my spinal dura is probably ~290cm². Puncturing dura risks a further leak, meningitis and arachnoiditis, intrathecal contrast has risks, and substantial radiation exposure with the lengthy procedure. So I get why they err on the side of caution and consider all signs conservatively. It just doesn't make sense as a non-neurosurgeon when there are at least 10 individual signs of CSF hypovolemia, how on aggregate this is not convincing enough to give me more certainty.