Help with insurance appeal for surgery

I’m stuck in a loop and do not know what to do from here.

4 years ago I had a 2 level fusion in my neck.

It still hurts radiating pain. 3 MRI’s and the join did not fuse. Almost zero % has fused together.

I’ve also been to 3 different doctors who all recommend a revision surgery.

I did 2 months of PT which actuate the pain worse.

The insurance company keeps saying we do not see any evidence that you need a revision surgery.

Yet 3 different doctors who do not know each other have all said “this is pretty bad, it’s not fused and needs to be fixed”

3 doctors: he’s in pain he needs surgery Insurance: No he’s not we’re not paying for it

What do I do? Do I get a lawyer? I feel stuck and no one can give me a specific answer.