A CT scan is the gold standard for fusion determination. X-rays are easier to obtain so I generally start there but if you can get a CT scan, that would be helpful. Surgery can be permanent at that level if you have a fusion and it heals solidly. An artificial disc replacement can be helpful in the correct circumstances but will eventually one day wear out (after all, it is a mechanical device) and need to be revised.
For lower back pain, if massage helps, then use that therapy as long as it works and is not too frequent.
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.