You have two relatively large herniated discs at L4-5 and L5-S1 which have appeared to compress the right sided nerve roots. The typical presentation of numbness, pins and needles and pain accompanied the nerve compression. I will assume you have no motor weakness of the foot dorsiflexors and plantar flexors (you can walk on your heels and toes for some distance without fatigue or weakness).
You have participated in physical therapy for the last six weeks and have improved significantly. The symptoms now are annoying but not disabling. Again- assuming you have no motor weakness, you can try to continue conservative treatment.
You have a genetic predisposition for herniations based upon the 2 levels and the large size of the herniations. If the herniations stay the same size and do not enlarge (recurrent herniations), the chance of cauda equina syndrome is remote. Over time, these herniations will shrink down and become less inflamed. There is a chance of recurrent herniation with or without surgery and no one knows the exact incidence of that possibility in your particular case.
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.