Like you, I had big-time back surgery, over 27 years ago. (1.5" of the T-5 vertabra and a rib were removed. I recommend this procedure to all my enemies....) Eventually, my homemade rehab program was extremely successful, but it took years and years to get back into competition powerlifting and pull my best deadlifts.
Start EXTREMELY light, with very high repetitions (15+) in all of your lower-body work. By now, you know the difference between "muscle/tendon stress pain" and "skeleton in danger pain." At the VERY FIRST MINOR TWINGE of the latter, STOP! Then, experiment with other (extremely light) exercises that target the same muscle groups. Add more weight, VERY gradually, as you get stronger.
It's a common misconception, that you can you can "spot reduce" the fat overlying a muscle, by exercising that muscle. If you burn 40 fat calories, and if, for instance, a quarter of your total bodyfat is in your love handles, you might have burned, roughly, 10 fat calories out of the love handles. You can make 'em much smaller, by reducing total bodyfat, but it's a lifetime project. Learn all you can about nutrition. You may find that what works best for you is changing WHAT you eat, not HOW MUCH you eat.