ABSTRACT
One of the most significant developments in medical device regulation has been the emergence of an appreciation that pre-market approval processes cannot eliminate all possibility of problems. Some of the problems which have gained world-wide attention in recent years, such as polyurethane pacemaker leads (Stokes 1998), the Bjork-Shiley heart valve (Lindblom et al. 1989), silicone gel breast implants (Snyder 1997) and several kinds of artificial hip joint, have become apparent many years after implantation.
