Zinnia,
I had a big problem with CSF and hydrocephalus but it was taken care of before the tumor resection. The shunt installation took place one month before the tumor resection. Excess fluid puts pressure on the brain and compromises equilibrium.
I'm a runner. When I was jogging downhill (before the shunt surgery) I could not stop running or even slow down unless I grabbed on to something like a sapling or a street sign to break my forward momentum; I'd stagger around like a drunk and could not, for the life of me, walk a straight line. If I stopped short on a downward incline even when walking, I'd start to fall forward and could not stop from falling flat on my face. Also, my hand writing deteriorated (I'm left-handed). Although I was still very sick and not out of the woods yet—after the shunt surgery and during the month in-between the main event surgery—I noticed a dramatic improvement in my gait. I was more sure-footed.
I still have the shunt and will have it the rest of my life. It doesn't hurt at all. However, the appearance of a shunt can be rather unnerving. I have this weird protrusion under the skin on the crest of my forehead with the indentation of a hole drilled through my skull and a catheter that runs across the side of my head, down the side of my neck, across my right pectoral, that disappears into the abdominal cavity where the fluid is absorbed. My hairline has receded which doesn't help. If you have a full head of hair you'll have no problem hiding it. This sounds a lot worse than it really is.
That you have CSF build-up after the tumor has been removed seems unusual. Hopefully it will be taken care of without additional surgery.
Best regards.....