As far as I know, the only regulation is
21 CFR 822 which is a mandated postmarket surveillance; i.e., the FDA calls up and says do this. Of course, with your normal risk management activities, you should be continually assessing postmarket data (complaints, AEs, similar products, etc.) to ensure your risk file is up to date and your device is meeting safety and performance requirements. I just don't think there are any specific reporting requirements (unless mandated). (There may be annual reports and such, I believe, but not like the CER or PSUR.)