The IVC filter (or they have been calling it a Greenfield filter) is a little thing like an umbrella without the material attached. Picture is on wikipedia >>
The surgeon is going to insert it through an incision in her leg (about 1" incision very small) and then work it up to her inferior vena cava below the heart. This is the most typical type of filter used for people with Pulmonary Embolisms/PE's/clots in the lungs. I think that this is going to be a permanent thing... no one has said anything about retrieving it after a certain period of time (and I forgot to ask) but apparently people have had them in for years and have had no complications.