Mri: l3/l4-disc bulging abuts thecal sac, superimposed facet degenerative changes, loss disc height. could my l4-s1 fusion have made worse?

There is a condition: known as adjacent segment disease in which a fusion may lead to altered spine mechanics and place increased load on the next adjacent spine segment but there may also be a genetic basis for this -it may also be due to smoking as well as to being obese . May need to also focus on core strength ending exercises but talk to your surgeon too