Well, so long as she's given the clear, I would just ... be careful.
I think that bounces would be really good for her overjumping, but I don't think they would be ideal for her back AT ALL. So I would steer clear untill the back problems were completely cleared. Maybe you could start with lines? But big lines - 3 or 4 minumum. I think putting ground poles down for 4 or 5 strides before the jump would be awesome! Just trot everything (trot poles 3 steps apart, 6 steps right before the jump). Start with small jumps, and build up slowly.