The present invention is an occlusion device having a collapsible frame which allows the occlusion device to be more easily centered in a defect and retrieved in situ. The occlusion device comprises a first post configured to be located on a first side of a defect, a second post configured to be located on a second side of the defect, and a fixation device connected to the first and second posts. The fixation device is used to hold the occlusion device in place across a defect, and comprises several segments. The segments are shaped so that each segment comprises a loop, causing the fixation device to resemble a "daisy design."