Scoliosis and Ab workouts

I was told by a Chiro when I was younger that I had scoliosis. No indication that I need a brace but now I am trying to do Ab workouts but I’m not getting good results and I feel it is due to the fact that the scoliosis made me very sway back.
I therefore can’t keep my lower back on the ground when doing the exercises the way they say to. Are there any exercises you know of that I could do for my Abs since I have the curvature of the spine??????