If I understand you, at the place you were fused C5-6, with rods etc, this is now getting compressed to narrow your forminal canal, correct? Was there any mention of bone spurs?. Usually with that surgery, the forminal canal is opened so you don't get any more compression. Disk is romoved 100% and then replaced with doner bone, or a segment from your hip. All of mine were replaced with doner bone.
If you are not getting a good response to answer your issues with your current doctor, go get another opinion if you can. I did not stick with my origional surgeon as I wasn't happy with him leaving the rest for later and not telling me anything. sometimes these neuros don't want to admit when a proceedure didn't turn out exactly like they wanted. If you are in some pain, you need to get that doctor to talk to you. I would hate to think, that it is possible for compression to happen, to those verterbre, that are fused with rods and plates. That is scarry. No wonder you are worried. You don't want to have to do a re-do if you can help it. How are all the other verterbre above your fusion site? All mildly hernited? Does it say "severe" anywhere in the MRI records? This is an indicator. Using the word "mild" the surgeons usually don't do the surgery. If it is severe, and narrowing takes place, they recommend so you don't continue to get shocks up and down your arms.
All and all I do not regret having the second fusion, but I do wonder how long the ones below will last and I do have a concern about that. I hope both of us do OK. Please ask your doctor these very questions you have, he owes you a truthful answer. ginnie