Hello.... You have not mentioned the symptoms that you are experiencing. A reduction in disc space without any symptoms does not necessarily warrant treatment. It would also help if you could tell me your age since some disc space reduction can occur as a normal part of aging. A significant reduction at L5-S1 could suggest lumbar canal stenosis and would cause symptoms such a low back pain and radiating or burning pain along the back of the thigh and in the legs. If you are experiencing these symptoms please consult an orthopaedic surgeon who would guide you as regards the further course of action. You may need to take lumbar traction along with calcium and vit.d supplementation. Severe lumbar canal stenosis would require a surgical prrocadure known as laminectomy. Hope this helps... Regards,