There are past posts about blocks , you can use the search link to find them. I don't know of anyone has posted about block much in the last year so it might be back in history a bit..
I never got to that point so can't give any first hand info..
Since you have the cervie ribs and they have bothered you for many years, why not get them removed?
Usually that has good results , as there is actually a cause of the compression, not a guesswork thing like with unclear causes. Of course if the nerve has been compromised recovery may take longer than is mainly vascular.. But the sooner you get the pressure off the nerve .....

Oh Now I see at the bottom you are heading to surgery this summer..