You don't even have to complete a surgery resdiency. As long as you have a medical license, you can do whatever you want. The license says you can practice medicine, it does not restrict you to any certain field. Now, that doesn't mean you can get hospital privleges, but you can work in your own surgery center.
I know of an internal medicine doctor, who did plastic surgery out of a day spa. Her husband (an EM physician) did her anesthesia. She went to a couple of courses to learn how to do liposuction and such and came back to do plastic surgery. She had a couple of complications that ended up in the hospital from acute blood loss anemia. Of course, she had no hospital privileges so the trauma service ended up with the patient. All of her assests were in someone else's name, or she had her company set up as an LLC, so I don't think she actually has lost any money secondary to law suits.
She does currently have her license suspended for narcotics abuse. I think she was prescribing Percocets to her patients, but she was getting the script. So, yes she is no longer practicing, no it is not as a result of her practicing surgery outside of the realm of her training.
