Re: disc implants
Currently in the US we are restricted to 1 artificial disk in the cervical area. You have Harrington rods which attach to the sides of your spine to hold the spine in proper alignment so you aren't fused...are you? Do you know?
If not, you may be able to get an ADR(artificial disk replacement) except that you might already have screws in C6-7 from the Harrington rods. And if you are fusing from the Harrington rods, that would exclude you. You'd be better off with an anterior ACDF to fuse C6and 7 together with plates.
Usually, ADR's are only used when there is no other pathology then 1 bad disk.