You have had a unilateral (one-sided) spondylolisthesis for years. I am unclear about the location of the spina bifida occulta (split in the back of the lamina) but this does not matter if it is in S1. The spit would have to be in the L5 lamina to make a difference in treatment.
If your disc is still intact and you have no slip, the pars can generally be repaired surgically. If you have any substantial slip or you have a degenerative disc at L5-S1, you would need a TLIF fusion. You could then reestablish yourself in sports after recovery from a successful surgery.
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.