I had an interthecal Medtronic pain pump implanted for over 18 years until I had t removed. It worked very well for my chronic pain , with no side effects at all that I noticed (important to consider). Clear minded, no constipation, etc. This is not a simple issue for there are many variables. Something to consider, with the large morphine dosage (massive really, if you are correct) some pain relief should have been noticed! That leads me to believe that the catheter placement is not correct. It seems it may not be positioned at the exact location of the pain generation. I have much experience and there might be others issues to consider, but I just noticed your post and quickly wanted to alert you to that option (maybe you already knew).