Linda, I was going to have an RFA done at L4-L5 bilaterally, but my PM said that the test to see if it (RFA) would work, was to do facet joint injections, to see if the injections relieved the pain. He said you get two sets of the injections (if the 1st one works). I did them, they did help, but then I chickened out on the procedure. I googled it, and found the success rate fairly low (I think it was about 33%, but that is a guess). Plus, I asked my OS about it, and he said he had patients come back to him where they did not work. But he also said, it doesn't mean that some of his patients had them, they worked, and did not come back to him. He did not advise me, because I had already decided I really did not want it.
There was a lot of info on BT, and I hope you can find the info you need.

I am 47, and my PM didn't mention a thing about age and long-term effects. So, I think even the doctors do not have the same opinions. Maybe a second opinion? Good luck, and I hope others come through with their experiences. I know there were alot on BT that they worked for, and alot that they didn't work for (I posted the question there, myself).
Carolyn