Hi Steff,
Im sorry but I cannot help you with this block. But I have had a Bier Block which did not help at all - it made me worse. Most doctors can make a diagnosis without you having to go through the all the stress of having a block.
If I was you I would talk to your doctor or consultant about what he/she suggests. If you do decide to have a nerve block ask your doctor about the side effects and also ask for a percentage of the success rate
Sorry I cant help
Alison