please help me understand my ct lumbar

Question

I have a grade 1 retrolisthesis of both L1 on L2 and L2on L3 noted. The intervertebral disc spaces mild to modertely narrowed throughout the lumbar spine. Prominent disc bulge noted in the lower lumbar levels. There is suspected moderate to severe central canal stenosis at L4-L5 secondary to disc bulg and ligamentum flavum hypertrophy.