If you are concerned about your procedure, you said are going to ask your doc the? Here, so couldn't you call the hospital and ask them about it and someone there inform you of the process of the procedure, I would suggest looking into that, After all it's you getting operated on. I don't know if they will, but why not ask about and see what they say.

If I recall correctly they often secure a patient to the operating table because there narrow. When they do so they'll place a strap across an individuals abdomen and the thighs or legs. 🤷‍♂️

It really depends on what they're doing.

I think they had a couple screws in my head as well.
I wouldn’t be surprised.