I don't know but for me and I have not allowed a doctor to take them lately cause it causes too much pain mine seem to vary. I think it is from being so tense as I can't relax when I know it is going to hurt. I am not saying this is you and who knows with me. It may not be from tension. I am glad your doctor ordered another mri. What about emg/nc does that test again to see progression?I wish I had more ansers for you. Have you ever tried pool therapy or been suggested it? I just suggest that cause I have been thinking of it again and out of all the PT type things I hear the best about the pool. Of course go with your doctor suggestion and your body. Sending thoughts