my doctor wants to do this because he wants to see which disc is causing the pain... L-4 or L-5 S-1. Is this really necessary? i'm confused. i realize that they want to narrow it down and avoid any un-necessary surgeries, but it seems like they aren't listening to me. i say the pain is coming from L-5, S1. they also mentioned disc replacement. ha! yea right. like that's ever going to happen...i'm afraid and in loads of pain daily.Can anyone offer any advice?