treatment for low back pain? had mri and discograph?

resulting in degenerative disc at L5-S1 with central disc protrusion with contrast tracking from nucleus to posterior annulus in midline. Not resulting in nerve root commpression or highgrade foraminal encroachment. also no spinal stenosis or highgrade thecal sac compression.Tried all types of therapy ie;facet and various injections and physical therapy. wanting to know if I'm cadidate for surgery if so what type and or any other methods of treatment