I have the same information as the others. My Dr. also said they would not be able to tell if there was a fusion, for at the minimum of 12 weeks. Even then, when i was not fused at 12 weeks, my Dr. said it could take up to 6 mo. for some to show up. So, I'd say not to worry at this point.
I did use an external bone stimulator after my 2nd fusion, but only because my 1st fusion failed. I'd say the best thing you can do is not put yourself at any additional risks of breaking a fusion. Be careful driving, not only becasue of accidents, but because you twist so often when you don't even realize it. Make sure you are not bending, twisting, lifting, reaching, etc. I was told that doing these things before a fusion was seen, could hinder a fusion from forming. I don't know if you are planning on going back to work at any point soon, be careful to stick to your restrictions...until there is a fusion seen.
As for what happens if you don't fuse, my Dr. told me after my 1st faild fusion, that eventually, he would have to go back in to at least change out the hardware...since he used small screws that were meant to only assist the fusion. W/o a fusion, they were not strong enough to support the spine on their own. However, until they started to cause me a problem, he would nto recommend going back in for that reason. He also said that if because of the failed fusion, my pain cont. to worsen and it got to the point of me not being able to live any kind of life, then he would go back in and try to re-fuse me with BMP. BMP, being a special fusing material that hardens faster and more often.
I wish you the very best,
Lorie:angel: