This document discusses investigational device exemption (IDE) and post marketing surveillance. IDE allows investigational devices to be used in clinical studies to collect safety and effectiveness data, requiring approval by an institutional review board and FDA for significant risk devices. Post marketing surveillance monitors the safety of medical devices after market release using approaches like spontaneous reporting databases and patient registries to identify potential safety issues and provide long-term monitoring of effects. Both are important parts of ensuring device safety during development and after approval.