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.