@helenr, @bernese53 : to both of you Helens – I did not have a herniated disc, but one of the discs between two of my vertebrae has completely collapsed and dried out, the facing vertebrae surfaces look like serrated knives, very rough. Also caused significant sciatica. Had 2 guided cortisone injections, simultaneously started daily (and I mean daily!) back exercises. Some flare ups from time to time, but otherwise under control since spring 2016, and counting. Without the PT intervention I might have been headed for surgery sooner or later.