I have chronic lbp, post scoliosis reduct surg, numerous fusions. When I need to have bowel movement, there is always lbp w/pressure. Ideas why?

Degenerative disc. Below fusion forces transfer to other levels dd accelerates bad disc aroind fusion whichvlevels did you have done pain withbm is a disc symptom.
Bowel problems. If you have been taking pain medication for a while for your low back pain, the most likely explanation is that you have excessive stool back up from the use of pain medication. The simple treatment to try for this theory is to take an otc product called miralax, (polyethylene glycol) a white powder. Pour the powder into the cap to fill it, then dump the cap into a glass of water or juice. Take 1 capful a day to see.