I had Chronic sinusitis for many many years, although this was back before i was a pilot.
so by the time I applied for my medical, the situation was considered resolved.
I had FESS and a deviated septum corrected.
was the BEST thing ever for my sinusitis. No more sinus infections, can breathe again.
The only thing it didn't cure was the post nasal drip. I still get this, its a minor irritation.