What does it mean to have mild dextro scoliosis of the lumbar spine with mild degenerative changes l5-s1?

If you are not having back problems these are not significant. Scoliosis is a twisting of the spine and a mild amount is common. L5-S1 is the lowest portion of the spine and compression of the nerves in that region is unlikely with only mild degeneration.

Your films are reassuring and do not reveal any significant or "surgical" pathology. At age 66, mild wear and tear arthritic changes are not unusual. If you suffer chronic back pain, some physical therapy and back exercises should help.