i have had a fusion c5-6 in 2005 and they diagnosed me with 20 % disability. I have been dealing with pain off and on since then but dealt with it. in 2009 i was in a car accident where i was rearendeed by 2 cars. i had man things checked and said i had c6-7 barely pushing out but didnt need any other treatment. No i have been having pain and numbness in my left side. alt of pain. i had another mri done withing the last week that showed i have bulging disc that is pushing against my spinal cord causing the pain and numbness. then they said i have thinning or narrowing of my spinal cord . They said i will have to get with neurologist and another dr to see what can be done.
Getting a disc, instability, subluxation and spinal cord impingement at level adjacent to previous fusion is a possible phenomenon at the rate of 2.5 % per year chances.  You Would need to be had surgical if a conservative treatment Has failed or there is weakness or loss of balance. You should see a spine surgeon for this.