This MRI report was written very poetically. This indicates that the “tracks” are the surgical scar tract that is always visualized after a lumbar spine surgery. The L4-5 disc has some degenerative changes. The L5-S1 disc where the previous surgery occurred obviously has some degenerative changes and the “altitude” changes are the narrowing of the disc space after the herniation.
There apparently is a recurrent herniation at that level that causes some compression of the S1 nerve root in the lateral recess.
Your doctor is correct. Without motor weakness, you have two options: to wait or to have surgery. This is a value judgement that only you can address. Benefits of waiting are that you avoid another surgery and the benefits of surgery are that a direct decompression of the nerve root has a good chance to give you relief of your buttocks pain.
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.