I am highy nervous about having spinal decompression and fusion surgery. mostly about not waking up and fusion failure. why shouldn't i be?

You are not alone: These are major surgeries which will take many hours and complications can occur, thus your emotion/fear is not uncommon. I am sorry to hear that this is something you are about to endure. I assume you have been suffering pain/disability for quite some time now? Talk to your family/friends. Discuss your concerns/fear with doc. There is no shame in doing that. I wish you the best of luck.