unlikely to cause any adverse health effect. In 2009, FDA reported that there were 160 Class I recalls, over 500 Class II recalls, and 172 Class III recalls (FDA 2010a). Not all the recalled products were in clinical use, so the recalls may have prevented additional future exposures.
Many recalls of implanted medical devices are based partly on postmarket surveillance data. A universal, one-size-fits-all system for medical-device reporting and postmarket surveillance has not yet reached the level of success that FDA would like. The existing FDA medical-device reporting systems—Manufacturer and User Facility Device Experience (MAUDE) and Medical Device Reporting (MDR)—contain a great deal of information that cannot be reliably analyzed, and the agency is studying new approaches to postmarket surveillance under the Sentinel Initiative.
Under MDR requirements, manufacturers of medical devices are required to report deaths and serious injuries caused by malfunctions of medical devices to FDA. User facilities are required to report serious injuries associated with medical devices to their manufacturers and to report deaths to both the manufacturers and FDA (FDA 2009a). Data from 1991 through 1996 are in the MDR database, and data from various sources from 1991 to the present are in the MAUDE database (manufacturer and user-facility reports since 1996 are included in MAUDE) (FDA 2010b). Although the systems include useful information on the number and types of adverse events associated with medical devices, they do not include clear information on the number of people who use the devices, and that makes it difficult to estimate the rate of such adverse events and therefore difficult to detect changes in the rate.
Medical-device registries have some appeal, but it is probably not possible to implement them for all medical implants that are in general clinical use. There is a device registry in place for ventricular assist devices (VADs): INTERMACS® (Interagency Registry for Mechanically Assisted Circulatory Support) is a national registry for patients who are receiving mechanical circulatory-support device therapy to treat advanced heart failure. This registry was devised as a joint effort of the National Heart, Lung, and Blood Institute, the Centers for Medicare and Medicaid Services, and FDA and was formed to analyze clinical outcomes, device durability, adverse-event rates, and costs. Analysis of the data collected is expected to facilitate improved patient evaluation and management and aid in better device design and development. Registry results are also expected to influence future research and system design and facilitate appropriate regulation of VAD implants. About 85% of all VAD implants are enrolled in the registry (D.C. Naftel, University of Alabama at Birmingham, personal. commun., March 7, 2011).
This case study focuses on medical implants that make direct contact with tissues other than the skin. They constitute a pool of about 20,000 medical im-