Skeye sorry to hear that your having such a time. I can imagine with all the med changing you are certainly have some w/ds thrown in ontop of trying to treat the pain.
I have thru the years seen folks who seem to be opiate resistant and whether Docs actually acknowledge this can and does happen I just dont know.
Like Tony in those I have known methadone has been their only choice and turned out to be a blessing as well. It most likely has to do with the fact it hits on a totally differing receptor then anyother opiate.
I have known more then a few who no matter what they were given or how high the dose absorption was a factor in its failure.
I have seen some success in the ketamine trials but not alot of maint. use for some reason and likely the danger of the med and its side effects.
I dont know if you have tried methadone as of yet and I am NOT an advocate of doing so until all else fails due to its potential to be most difficult to adjust to and near to impossible to ever get off of but it may be your last resort and blessing as well.
Good luck to you and I certainly hope they find something that works soon for you.