Congratulations on making the decision to tell your parents. It sounds like you've put considerable time into contemplating your reasons for wanting to tell them, plus you've pondered how you will tell them. This is a big step in your recovery, and in some ways it's the hardest step. I recently told my parents, and it was a very positive experience. I'm very glad I did so. I realize not everyone will have the same experience, but I'm glad I did. Only you know the type of people your parents are, and what relationship you have with them. Prior to telling my family, I had the very same questions that you have. You only need to reveal what you're comfortable with. You are not responsible for your parents' reactions. They will be hurt, without a doubt, but they are also adults who, theoretically can handle this. It is admirable that you are taking into consideration their feelings, but they don't have the right to go through life without ever experiencing hurt and pain. It's not necessary for you to endure unneeded stress and anguish to ease their psyches. It's a good idea to plan how much hurt you'd be able to handle should you experience a bad reaction from them, and limit yourself to stating only that much of your story.
You don't need to name names initially. You can always tell more of your story later, but you can't go back and undo it if you say too much too soon. Actually, when I told my mom, I did just say " Mom, there's something I need to tell you. In my past, I was abused." It worked and if you decide that's how you want to tell them, do it. The simplicity and candor of just blurting it out makes it easy for you to get it out, and almost impossible for them to mis-interpret. If you can think of a different way, you can do it too. There's pretty much no way to screw it up.
Good luck Buffalo. I wish you well and I hope you have a positive outcome. Please let us know how it goes.