I have to disagree with Peter. Many American doctors perform nerve-sparing surgery that enable patients to have an erection after their RC.
Of course sometimes the nerve--because of the patient's situation--can't be spared and must be removed. That was what happened in my case. But it wasn't because American doctors can't or don't perform nerve-sparing surgery, it was because I wasn't a proper candidate for it.
But as you can see below, my surgeon frequently does nerve-sparing surgery:
www.usc.edu/schools/medicine/departments/urology/about/profile.php?PersonIs_ID=2733