DAnn (Diane?), Similar to Jeff I had a C5-6 fusion ages ago, but when I had a lower back problem I ended up with prodisc-L at L4-5.
I was refused by my health cover (Bupa), but I wrote back and complained. I was helped a lot by the UK Financial Ombudsman's website (they are the regulators for Bupa) and I got tips there on what they can and cannot refuse.
You should ask you health fund for a detailed reason for their refusal. Bening a researcher you'll then be able to look up the successful ways to beat their refusal. In this day and age ADR shouldn't be treated as experimental Bupa initially took this take with me (verbally) and I found another UK organisation called NICE (National Institute for Clinical Excellence
Welcome to the National Institute for Health and Clinical Excellence).
They specifically state that ADR is NOT an experimental technique and is the same technology as hip replacement. Health funds just don't want to pay if they can avoid it.
Good luck!