I'm in your boat however have had the infection for 6 years in my left frontal sinus. I've had 10 lots of surgery includling 2 lothrops. Surgery is no longer an option as not much left to take out. I have osteitis of the skull base which seems to be cause of the prob which has come about by a mis diagnos of the frontal sinus being infected. I'm now onto my 4th professor who is having a go at trying to solve. Like you my skull base was infected and they have drilled the intected bone out before it got to the fluid round the brain (can;t recall medical term).
We are now trying to treat the pseudmonas infection with ciprofloxacin, tobramyacin soaks, washes with johnson and johnson baby shampoo mixed with pulmicort and doxycline. All IV treatments in hospital have failed...
This bug is a nightmare, but i'm still figting it, albeit with stuff all sucess but have to stay positive. Keep positive and keep me in the loop om your treatment and if you have any wins. Will ensure if we hit the jackpot that i let you know.