Currently, minimally invasive cardiac surgery (MICS) has been developing and has been largely approved for mitral valve surgery. The more development of MICS, the more the entire surgical setup needs to be appropriate. We developed a homemade tool for mitral annular sizing that is simple and fits the mini surgical access. It is a plastic-based foldable paper that can be easily inserted through the minithoracotomy, using a surgical forceps.
