I had a fusion with instrumentation at the L4-L5 and L5-S1 levels. I had the surgery and then found out that the nerve damage was permanent. I am taking Lyrica (which is for diabetic nerve pain) but it works just the same. The back pain is better but still there and nerve pain is not as bad. The medicine seems to help but we are still playing with the dose but it is better. If the nerve damage is permanent they can put you on medication. From what I read alot of people have the nerve pain after surgery and then it finally goes away. I think the risk is low that it is permanent. We almost knew mine would be permanent when going in to surgery because I had lost complete feeling in my right leg and had bladder problems due to the damaged nerves. It is possible but I don't think it happens often alot of times it just take a while the the nerves to heal.