Traing lower abs with herniated discs

Any help would be greatly appreciated! I have been training for aprox 20 years now and about 6 years ago i injured my back, the outcome l4, l5 herniated discs. I have come along way since then and have been training hard esp over the last 4 monthes. I lost 30 lbs with a strict diet, weight training and two cardio sessions daily. During the last 4 monthes i have been training abs but basic staion exercises, ab rollers, ball crunches and a few machines you can add weight to. I now want to do a physique show in Nov and need to train my abs harder so they pop more. I started a new routine this week which was windshield wipers, leg raises and decline leg curls. I feel crippled now and i know it has to be from these exercises. The question is can i develope great abs with a herniated disc? If so, what exercises can i do to get these and compete without injuring myself?