Need more "filter" info

Hi Guys: I need some more info on filters used to prevent blood clots. One doctor absolutely won't do surgery without it if your bmi is over 50. Another doctor says that just the process of inserting the filter presents a big risk of causing blood clots. HHmmmmm that gives me a warm fuzzy feeling. I'm a very healthy male at 395 lbs. I will be having the DS surgery in Mexico or Spain just as soon as I can make it all happen. Been told I'm considered "low risk" (if a fat person can be considered low risk) because I don't have other co-morbidities. But, if the filter is as wonderful as they say it is, then I'll have it inserted before I go to Mexico. I am having to pay for all of this myself, so, of course, cost is a big issue. Does anyone have the scoop on this? Is it painful-? I hear that there is one kind that stays in for life. What is the cost-? Thanks, Ray Bechtel