At L4-5, there is mild disc height loss, disc desiccation, and a small diffuse disc bulge with posterior central annular tear. This results in only minimal effacement of the ventral thecal sac and inferior bilateral neural foramina without nerve root displacement or compression. Mild bilateral facet arthrosis is visualized. At L5-S1, there is redemonstration of grade 1 anterolisthesis and bilateral late subacute to chronic pars interarticularis defects. There is only mild posterior uncovering of the posterior disc space but no significant central spinal canal stenosis. There is mild bilateral facet arthrosis. There is mild bilateral neural foramina narrowing in a right greater than left distribution with suggestion of mild mass effect on the exiting right L5 nerve root. (Image 3 series 7) The visualized upper sacral levels are unremarkable. WHAT DOES THIS MEAN??