Coming from someone with fairly significant low back problems...
There are thearapeutic things you can do for you back but doing and of course you are going to want to strengthen your lower back but doing any other movements for any length of time is not suddenly going to make your proficient on the deadlift. If you want good form you have to learn good form even if that mean you start out with only the bar.
But let me tell you...I deadlift a shitload now but I've never progressed without form following. I've always adhered to that. Deadlift doesn't agravate my back as such as long as I concetrate. It is other things that do it. Bent over rows have a much better chance, for instance. Other variations of the deadlift also.
Here's my little speal on deadlift. It is not a spinal erector dominant execise and so is not really a "back exercise" as far as that. You entire back gets the hell worked out of it but as soon as your lower back is actually "doing" the lift you've fucked it up. I know some people dl like that all the time. But you want see them doing it when their my age
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It is a hip-flexor dominant exercise, imo. That means if you do it right the hams, the glutes (I feel it big time in the ass) and the erectors must work in concert to pull it off. No one muscle shoulders the entire load but the entire posterior chain. If you learn to do it correctly it actually becomes a lot safer for you lower back than some of the other common exercises we do.