Classifying Medical Devices - Medical Device Design: Innovation from Concept to Market - page 11

CHAPTER 2
Classifying Medical Devices
2.1 Introduction: Why Classify?
There are a number of reasons why classification is important. The first concerns the patient.
Clearly the more risk a given device poses to the patient the greater the reassurance that needs
to be given. Not all devices pose the same risk; consider for example a pacemaker compared
with a support bandage. It is quite clear that the pacemaker poses the greater risk and, thus,
should have more stringent controls attached to its design, manufacture, and eventual sales.
The second reason concerns the manufacturer; why should the registration process be as
stringent for the support bandage as compared with the pacemaker? The third reason concerns
the regulatory bodies; the classification indicates to them the level of risk to the patient and
the nature of the beast they are dealing with, and hence the amount of effort they need to put
into the control . After all, governments have limited budgets too and they need to target their
resources at the devices that pose the greater risk.
It is obvious that the prime importance is safety . Although patient safety is a priority, one
must not forget the users; their safety is just as important. All devices have to obey the prime
criteria do no harm . But it is also clear that, for some devices, to achieve a clinical goal some
harm is inevitable. The question posed is, “Is the risk acceptable?” Consider, for example,
a hypodermic needle. Which is the greater harm, producing a small puncture wound in the
skin, or not receiving a vaccination? Risk and doing no harm is a balancing act. Classification
allows all participants in the regulatory process to understand the risk the device poses. In
general, the higher the classification the more chance that the device could do some harm.
Hence it should come as no surprise that things such as replacement heart valves are high
classification and inserts for shoes are low.
Table 2.1 attempts to illustrate how risk and classification are interlinked. Both the USA and
EU classifications are illustrated (do not use this for cross-referencing, it is only indicative).
The table demonstrates that low risk devices are Class I, and high risk Class III (note in
Canada there is also Class IV).
2.2 Classification Rules
Each regulatory authority has its own set of classification rules. In the USA these are
stipulated within 21 CFR Part 860 - Medical Device Classification Procedures ( FDA, 2010 ).