The medical device industry (at least in the US) is very special. It does not have retailers
per se, but there are a lot of middlemen who take varying, often enormous cuts. Medical device manufacturers make enormous amounts of money though. I am not sure how much of this is specific to the internal US market vs. carries over to US exports.
For a good treatment of this and many other aspects of US healthcare costs, see An American Sickness by Elisabeth Rosenthal.