For what its worth, my father had fusion done. He was 66. He was a large man(not fat) and suffered from degenerative back issues most of his life. He always worked through the pain, until he couldn't. The injections stopped working. It was hard to watch. He got the surgery, and it was a huge success. About a year recovery time with pt. My point is, the surgeon after the procedure discussed the operation and what he saw. When they were correcting the real estate, they uncovered his sciatic nerve from a destroyed disc. When they did this, the nerve immediately started to fill/flow blood. That was the first thing he noticed when he woke up was the strange feeling of no pain in his left hip/leg.