Mr.Bad : I have to tell you the longer I'm on this site the more I think the L4-L5-S1 area is just bad news.
To help based on my understanding he disc protrusion is probably where your disc ruptured and hardened outside the disc wall. In my case this is the area where the pain shooting down my legs comes from. At each level I have part of the disc pushing on a nerve. I have no clue what central canal stenosis is.
As far as surgery - thats a choice that you have to make. I waited 3 years for surgery after I hurt my back. I got a year and a half if that of pain relief from it, and the pain is now worse than it was pre-surgery. BUT I would do the surgery again in a heart beat given the choice. Because the relief I got from it was worth it. If he says he's referring you to a surgeon ask him about
his relationship with the surgeon prior to going, and do some research about
the surgeon. I know the surgeon who did my fusion had a couple arguing with him about
his refusal to operate based on the medical tests he preformed. He was basically telling them that based on the tests surgery was not going to fix the problem and they were not happy about
it. It made me feel good knowing that he would rather not operate if it wasn't going to help.