fibrous union in c1

Hello, i wonder if someone could help me or put my mind at rest please.
Im a 30 year old man and I had an accident while on holiday and broke my neck in 2 places.I fractured c5, and c4 was unstable so i now have those two fused together and all is well with them.
The main problem i have is that i also fractured c1 and was fitted in a halo traction vest which i have now been wearing for 3 months.I went to the hospital yesterday to have my halo taken off but have been told by the doctors that the fracture is not showing on the ct scan as uniting and so i have to go back in a few days time to have my halo taken off (as its loose and cant be tightened any more) and will have a series of tests, where the doctors will move my neck and see on the images if c1 is moving or not.
If c1 moves i will have surgery ( which i really dont want)  and if it doesn't i will be fitted with a hard collar.
My main question is, How likely is it that the fracture is healed but not showing on the ct scan, i have been advised it could be a fibrous union and wonder how likely this is .  Please can anyone advise . many thanks