Biomedical Engineering Reference
In-Depth Information
ankle contractures, tongue depressors, bedpans, bandages, examination gloves, grip
rest hand splints, hand-held surgical instruments, wheelchairs, and endoscopes.
11.5.2.2 Class II Medical Devices
Class II medical devices
are typically those where general controls are not sufficient
to assure safety and effectiveness, and existing methods/standards/guidance docu-
ments are available to provide assurances of safety and effectiveness. In addition
to compliance with general controls, class II devices are required to comply with
special controls including special labeling requirements, mandatory performance
standards (both internationally and in the United States), postmarket surveillance,
and FDA medical device specific guidance. Examples of class II devices include
physiologic monitors, X-ray machines, gas analyzers, blood pressure cuffs, oxygen
masks, infusion pumps, electrically powered wheelchairs, surgical needles and su-
ture material, acupuncture needles, and surgical drapes.
11.5.2.3 Class III Medical Devices
Class III Medical Devices
are those that cannot assure safety and effectiveness
through the controls of class I or II. Class III medical devices are those that support
or sustain human life, are of substantial importance in preventing impairment of
human health, or which present a potential, unreasonable risk of illness or injury
(21 CFR 814) [7]. The Federal Food, Drug, and Cosmetic Act (FD&C Act) section
515 requires device manufacturers to submit a PMA application to the FDA if they
intend to introduce a device into commercial distribution for the first time, or to
introduce or reintroduce a device that will be significantly changed or modified to
the extent that its safety or effectiveness could be affected. Under PMA regulations,
the FDA requires the submission and review of valid scientific evidence to deter-
mine whether a reasonable assurance exists that the device is safe and effective, and
has clinical utility. A scientific and regulatory review process is required to allow
marketing of a class III medical device unless an essentially equivalent device exists.
Class III medical devices need preclinical testing (conducting in vitro experiments
and in vivo animal experiments, obtaining preliminary efficacy, and determining
toxicity and pharmacokinetic information) and clinical trials (expensive, time con-
suming, and difficult to have concurrent controls for devices). Examples of class
III medical devices are replacement heart valves, silicone gel-filled breast implants,
pacemakers, defibrillators, vascular grafts, defibrillators, and drug-eluting stents.
PMA is the most stringent type of device marketing applications required by
the FDA. The PMA application approval is a private license granted to the appli-
cant for marketing a particular medical device. Recognizing the fact that to device
development companies, time and money are critical factors, the FDA has devel-
oped other types of applications which include:
Premarket notification
[Section 510(k) of the FD&C Act and popularly re-
ferred to as 510(k)] for devices similar to existing products already sold in
the United States.
