I had an acoustic neuroma removed via translab in October 2011. I was back on the bike about 7 weeks later. However, I was just taking it really easy riding on local greenways. I took it really easy for a year, and some things I noticed in the first year was looking left and looking over my left shoulder (my acoustic neuroma was on my left side). I found this to be very hard. I also found that riding in a pace line was more difficult. I had a harder time holding my line. Finally, the biggest thing was SSD on my left side - it made hard to hear passing traffic.
I really picked up my riding a year after surgery. I am not sure if my body had adjusted, I have just gotten used to it, I have just 100% healed, or all of the above - but the only thing I really notice now is the SSD, and I am not quite as good has bike handler as I used to be. I always ride with a group now because I feel more comfortable having more than one ear on the road.
I have done some big century rides with mountain ascents/descents and am on pace to ride 5000+ miles this year. I am also back up to an "A" pace. It may take a while to get back, but you will get back.
My best advice is ease back into riding, make sure you are comfortable, and be safe.
Ride ON!