Hi Liza, i think the ortho or neuro surgeon that done your back operation should be playing a more active part in all of this, if its above him then he should be reffering you to someone that can deal with it properly, loose screws is very concerning in an area that is so sensitive, i can't understand why that surgeon isn't doing something about it for you, you should not be left like this, its very unprofessional in my book.
Can't they implant a stimulator to accelerate the fusion or something ?
I hope things improve for you soon.

Brian