I think you may have misunderstood what Dr. Lasich meant when she said that degenerative disc disease is not a disease. Technically, that's correct. It would be more accurately defined as a condition rather than a disease. But it very definitely does exist. In fact, DDD is one of the most common causes of low back pain.
I haven't had the surgery you're going to have, so I can't give you any personal experience, but hopefully others here who have had the surgery will share their experiences with you.
I wish you the best with your surgery. I hope you'll keep us updated and let us know how you're doing.