Deb - So sorry to hear about your Dad's recurrence. A flap is a piece of tissue that is completely removed from its donor site wih an artery and a vein and will be connected to an artery and a vein at the recipient site. If you go here:
http://web.utk.edu/~aalix/abbreviations.html
- there is a list of abbreviations in case you need to look them up. It is really hard to get things 2nd hand. It does help if more than one person can meet with the doctors or cancer team. Did anyone else go with your Dad? Some even bring a tape recorder if it's ok with the doctor. My son's experience is slightly different from your Dad's, but I'm sure there will be others here than can help you with suggestions or information. My son had lymph nodes removed to make sure the cancer had not spread to them. Until other posters get to you, if you do a search from the home page or at the top of this one, you'll find lots of info on lymph nodes. You're right, knowledge is power and the more you know the easier it is to ask the right questions and be informed and ready to fight.