Before you go for the surgery make sure to ask all this to your surgeon.
There is nothing wrong about any of your Q? As long as they are the things that may bother you. Again it will be one on one, if you can ask this on iternet when billion of people can see these Qs? then you should be able to get correct answers from your Dr. Based on those, you may want to even cancel postpone the surgery.
It is a kind of support they can show you some pictures of the device. It does limits certain movements but not all. It may not be used or use all the time!
If they do not have the pictures then volunteer yourself to be use to show this divice to future participants.