Fig. 1.
A, Changes in original devices between 1980 and 2018. B, PMA supplements approved between 1980 and 2018.
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.