This is a rare kind of nerve disorder that can begin with numbness or weakness in the legs, or even one leg, and may have associated reflex losses. It could simulate nerve irritation from changes in the lower back, such as disc protrusion or spinal stenosis. I didn’t include it in my list of other conditions on this website. It’s relatively new and rare. If imaging of the lower back is normal, this condition should be thought about. You can’t make a diagnosis if you don’t think about it.
So if you have symptoms that have defied diagnosis you may want to Google CIDP and read about it.