First of all, sorry to hear that your back problems have progressed to requiring surgery. I know it is both painful and frustrating.
Here is a tale of two surgeries...
My wife suffered with chronic back problems for 25 years. Her diagnosis was degenerative disc disease which, ultimately, caused her lower three discs to fail. Over the years, she went through numerous alternative treatments, including physical therapy, steroid injections in the back, and pain management. Her sciatic nerve began experiencing damage (she would collapse without warning while standing or walking), she was up to eight Advil per day, and her blood pressure was no longer treatable with normal medications. With all other alternatives exhausted, she agreed to consult with a very well respected surgeon in the area (Dallas/Fort Worth). He had the bedside manner of a potato, but was very honest in his assessment - she had a 55%-60% chance of success with surgery (which could improve if she followed the recommended physical therapy to the letter) and a 100% chance that she would be in a wheelchair within three years without surgery. His recommendation was to replace the lower three discs and fuse all three together using two titanium rods. Basically, she was to be put on a rotisserie where they replaced the discs from the stomach, then rotated her over and inserted the rods. He had developed a proprietary real-time monitoring technology that allowed him to test nerve response throughout her lower body during surgery, so he could verify the degree of success for all procedures taken during the surgery.
Upon awaking in recovery, she was in excruciating pain because the new discs and rods were stretching her back muscles back to their normal length. This was normal, but not explained to us prior to surgery. They treated the pain with codeine, but had to incrementally ramp her up so as not to over-medicate. She stayed in the hospital for two nights, then was released to my care. Once the back muscles stretched (and after she was off codeine) and relaxed, she could really feel the improvements. She had to wear a custom fit brace for several months after the surgery and had a very structured physical therapy regimen, which she stuck to religiously. I was in-between jobs and able to stay home with her for two months. You WILL need some home help. It took almost a full year for her to return to her "new" normal. I say "new", because she does have some restricted movement. Now, nine years later, she will tell you it was the best decision she's ever made. She plays tennis, rides on the back of my motorcycle, and leads a very normal life. She used to ride her own bike, but gave it up about five years before the surgery due to the back pain. She is capable of riding her own motorcycle today (strength-wise), but chooses to ride pillion instead. She's also the first to tell you that if you don't trust your surgeon or aren't willing to follow the physical therapy recommendations, don't bother even discussing surgery.
We had a friend who also had severe back problems that he'd been dealing with for +10 years. He was very active in sports and business, and just couldn't be burdened with the problem any longer. He went to the same doctor, but the doctor strongly recommended against surgery at this time - basically refused to operate. Our friend wouldn't take no for an answer and found another surgeon (from a different practice) that agreed to perform the surgery. The surgery went fine, but the friend didn't follow the recommended physical therapy regimen and, eager to return to his sports, pushed himself too hard, too fast. Needless to say, he suffers from worse pain today and has very few options remaining.
Bottom line, make sure you have a strong trust in your surgeon and have exhausted all alternative treatments. In the end, the success of the surgery is probably more about you than perhaps the surgeon's skill. Don't wait too long...those years of taking 8-10 Advil a day caused liver and colon damage that she deals with on a daily basis.
P.S. Just based on your post, it doesn't sound like you have discussed the surgery and recovery expectations in nearly enough detail with your surgeon...or didn't take enough notes!
P.S.S. The bonus in all of this is if she passes before I do, I have permission to melt her down and use the melted titanium rods to build a new custom driver for my golf club set.