I don't have too much info but I hope this helps a bit.
The rather severe narrowing of the L4/L5 interspace with vaccum phenomenon basically to my understanding is that you have Degenerative Disk Disease and that is what causes disk place narrowing and endplate sclerosis. DDD means that there is a loss of water in your nucleous and that makes it collapse, then the two vertebrae above and below move closer to one another and that is what causes the narrowing of the disk space. As the shift occurs it affects the facet joints. I'm not 100% sure but I think that the moderate sclerosis of the facet joints is a bit of arthritis.
The Levoscoliosis means that you have scoliosis and your curve goes to the left.
Well I hope this helps a bit. I would talk to your doctor to get a better understanding of your diagnosis. Take care. Kristy.