Among other things I do planks daily - but I have found that side planks do not agree, so I don't do them. I am currently doing a couple of 100 second planks every day (don't sag your butt). Then I do bridges - using a fitness ball to raise my heels higher. I do 2 legged and 1 legged bridges. I use a bosu ball for more core work - I found a great video on the internet on bosu ball and core exercises.
Beyond that, I have a daily stretching routine and a whole variety of resistance exercises, rotating through various exercises, including body dips, pushups, lat and overhead exercises, back and pecs, etc.
I am pleased that I have made significant improvement in reduced back - and hip - pain this past year. I also take Celebrex.
I had an L-4; L-5 fusion about 18 months ago.
I would suggest you contact a good PT or personal trainer for a series of exercises just for you.