A solid fusion at L5 S1 would preclude having any subsidence of the cage. Popping and cracking noises are typically facet generated pain and noise. I would initially assume adjacent segment disease (L4-5) as you’re 5 years out of surgery but it’s a possibility that L5 S1 could be generating some noise. however, that would indicate that you didn’t have a solid fusion. There are very rare circumstances that the sacroiliac joint can create these noises but that would be unusual. I would 1st start off with standard x-rays including flexion extension for diagnosis.
Donald Corenman MD DC
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.