Hi ~ Did you have a CT Scan in December?? If not, you had better have a new one done to see what exactly is happening in there. In fact even if you did, you still might better have another one done. It might not be anything, but you just never know.
Unfortunately having these other levels rupture or unstable is common after a fusion. This happens all the time, because these other levels have to take more of the load after a fusion or even just a regular surgery without fusion. It's called the "domino effect." Just about everyone you talk to that has had fusion or surgery has had other levels go bad on them.

You are not alone.
I had 2 open lumbar spinal surgeries without fusion, and now other levels have gone "bad." Trouble is, because of osteoporosis I'm deemed inoperable so nothing can be done about it.
Call your doctor and see what he has to say. Or make an appointment and see if he'll run another CT scan. Let us know how you come out. God bless. Hugs, Lee