I Have A 2 Finger Long Indentation In My Spine

I have a 2 finger long indentation in my spine on my lower back it's about an inch long and maybe a quarter to half inch deep ... I have a history of degenerative disc disease joint disease and I feel arthritis as well as some spinal stenosis in my cervical and lumbar spine. I just noticed this indentation and didn't have it couple of weeks ago. I have had some intermittent weakness of my legs but not even every day maybe once or twice a week but didn't have it checked out