FDA recommends that you develop a schedule of key interventions and time points for your study, based on your knowledge of the known risks and predicted outcomes of use of the device. These timepoints typically include:

• full characterization, implantation, and intermittent examination of device performance and/or animal response
• explanation of the device (if an implant)
• full analysis of any explanted tissue; preparation of the tissue
• preparation and sign-off of the final written reports

FDA recommends that the QAU be aware of these key scheduling objectives so that interim study monitoring and inspections can be arranged. Because medical devices may involve some degree of invasiveness and predictable variability in animal survival, any anticipated change in the duration of study may necessitate adjustment of these parameters, depending on the interim data. For example, if adverse outcomes are detected at earlier time points than expected, you should consider enhancing the timetable for observation and device explanation so that useful terminal data are not lost. Also, FDA believes that the responsible use of animals optimizes the use of all animal tissue, and therefore recommend that complete gross and microscopic organ and tissue evaluations be performed on all animals and that tissue be freshly studied to avoid the potential for erroneous interpretation.