Well, Kurt did admit about the neck problem at the WM XIX when asked by a journalist about the rumor. It was after that, Cole/Tazz mentioned it on SD.
Kurt was then interviewed by WWE RAW Magazine later on and said he risked paralysis or death by toughing it, but didn't want to miss out on Wrestlemania (finally working to the top by main eventing it and missing it because of bad luck)? He was concerned about that experimental surgery and said that if it didn't work out, he wanted to give 100% percent in his thought to be last WWE match.
I'm glad he went through with it. He certainly deserved to have the spot and he did help put on a outstanding match.