A surgeon's assistant (more commonly referred to as a surgical first assistant or surgical assistant) is a medical or allied health practitioner that provides aide in exposure, hemostasis, and visualization of anatomic structures during the course of a surgical operation. Professionals filling this role come from diverse backgrounds and include medical doctors, surgical residents, surgical physician assistants (PAs), advanced practice registered nurses (such as nurse practitioners), specialized registered nurses (such as registered nurse first assistants or RNFAs), and non-physician surgical first assistant practitioners (SFAs) -
http://en.wikipedia.org/wiki/Surgeon's_assistant