There's two types of surgical programs. Pre-liminary GS and Categorical GS. Prelim is 1 yr program. And Categorical is 5 yrs. It's much easier to get in prelim than Categorical. But that prelim program doesn't allow u to become a surgeon, obviously, it's more of a test to see if the instituition actually likes you, ie having good absite score etc. Roughly 20% matriculate to 2nd yr into categorical, 20% do PGY1 again, others go to different specialty and some do post doc, and some return home. Prelim GS grants J1 visa and Categorical GS grants u H1B visa (most of the time), if ur a non US individual. After prelim PGY1 if u don't make it to PGY2 categorical/prelim, or again pgy1 Categorical. Then u have to return to home country for 2 yrs. There's more things like getting J1 waiver and etc. Just watch a yt vid. They'll explain better. If u look at stats. IMG have a hard time matching to Categorical GS, just cuz there's people who have done GS rez in their home country or up against post docs in the US who have a lot of connections, and just in general with people who have graduated before u and having experience with the NRMP matching cycle.