hi KBC

It sounds like the neurologist is trying to find the cause of headaches and dizziness rather than looking for the SCC in the spinal fluid (CSF).

We used to do spinal taps or lumbar punctures, to get CSF for to check for infection. The fluid was taken and sent to the lab for testing in exactly the same way blood is tested for various greeblies. We also used it to check pressure in the brain. The wrong pressure might cause headaches.

You can also administer medicines this way although I doubt your neurologist has this in mind.(think epidural during child birth)

The dizziness does sound like hypotension though and is very common as we advance in years (and also after radiation to the head and neck, I have learned). Does your husband experience this most often when getting out of bed or from a lying down position? I personally spent many hours on night shift "saving" our elderly who had got up too quickly in the middle of the night to go to the loo, and then collapsed in the cubicle up against the door making it very difficult for us to get them out. For a while they installed outward opening doors in toilet cubicles, until they realised the possibility of decking the unsuspecting nurse walking past as the patient was exiting was an even bigger hazard .

Let us know what the doctor said