Some people choose to have surgery before their hearing is lost, in hopes to keep it. I don't think there is a lot of good data with for example, hearing quality pre-surgery, and post-surgery 1 week, 6 months, 2 years etc. I think some folks can hear post-op but maybe not that great, and not sure if it holds up well down the road.
I was hoping they could save my hearing (retrosig in july) - I had 90% word discrimination pre-op but I lost 100% / am SSD post op. I knew I had only like a 50/50 or maybe somewhat better chance to keep it, but lost it. The surgery can cut off blood flow the auditory nerve, so even if the nerve is intact, you can still lose hearing.
i've seen quite a few other people post that their hearing was preserved post op, usually small and midsize tumors only - chance to save is worse as the tumor gets bigger.
If the tumor is still in there, some research shows it can damage hearing even when it's not growing because it secretes toxic byproducts. Not all AN tumors do this apparently.
I'm finding SSD to be pretty tolerable, it's hard in some situations with lots of people and bad acoustics around you. Most of the time it's not an issue for me.