Generally, it is rare for a degenerative level to fuse. I have seen auto-fusion but probably only one in every 100 severe degenerative change discs. What I think happens with pain loss over time in a degenerative disc is a cartilage endplate adhesion which acts like a fusion reducing motion and therefore pain. Fibrosis also occurs which “stiffens” the disc space. In addition, age brings reduced activity level and therefore less stress on the disc space.
Many patients have no pain with a severe degenerative disc (I call IDR or isolated disc resorption) until a stress force (a fall, impact or strain-lifting injury) actives the level and causes pain. It seems that these levels can stabilize sometimes for years (or forever) until some action destabilizes the disc. I see this all the time in the office.
Dr. Corenman
Donald Corenman, MD, DC is a highly-regarded spine surgeon, considered an expert in the area of neck and back pain. Trained as both a Medical Doctor and Doctor of Chiropractic, Dr. Corenman earned academic appointments as Clinical Assistant Professor and Assistant Professor of Orthopaedic Surgery at the University of Colorado Health Sciences Center, and his research on spine surgery and rehabilitation has resulted in the publication of multiple peer-reviewed articles and two books.