I want a flatter stomach but I have limited back movement.

[echoing8whisper]

I really want to have a flatter stomach, but I have two metal rods in my back (scoliosis treatment) and I have limited back movement.

As a result I can't do things like stomach crunches; etc.

Is there anything exercises that you know of that someone who has a 100 percent straight back can do to flatten their stomach?

because of the rods, my back is now a curvy S-shape and I can't STAND my stomach jutting out anymore!

[since because pickles]

♡
You can try laying on your back and lifting your legs in the air. If you can do that comfortably, try moving them side to side like a metronome, or lift your legs to your stomach and do reverse crunches. Those are only ideas - I'm not much of a fitness buff. Good luck!

[John Dapper]

Well, the only thing abs do in your body, is to twist your spine... While ab exercises will help shape your stomach, it is 70% diet and your body fat/genetics.

That being said, reverse crunches from a captains chair will help some. You can get plastic surgery for your abs, but that isn't recommended...

[catnapgood]

I agree with leg lifting exercises, those will target your lower stomach even if you can't quite get your upper stomach.
You can also do exercises that allow you lay flat on your back on the ground, but make sure you have support around you to get up correctly.

You can also consciously tighten and relax your abdominal muscles, though this won't have the best effect.

Most people with physical complications have to rely on a diet to help with weight the majority of the time.

[Anyriss]

http://www.gearfire.net/10-reasons-to-use-an-exercise-ball-as-your-chair/

It's really easy and sounds like something that would work for you.

[AIoof]

I have never tried this, but I am aware that Pilates was started for soldiers in bed who were unable to exercise because of injuries?

I'd say give Pilates a try because its history sounds suiting to your problem.

[Sliding Shine]

Either you can try Pilates, or try this:

https://shine.yahoo.com/video/top-ab-exercises-women-210034001.html