Classifying Medical Devices - Medical Device Design: Innovation from Concept to Market - page 15

But we must wait till later to check if other rules cause the classification to change.
I will not go through each rule one by one as this would make the text really boring. But you
need to read the rules completely and follow them through. It is important to note that it is
the rule that classifies the device that we need to concern ourselves with. The rules that do not
apply are, ultimately, of little concern. However, we will see later that monitoring this process
and recording our judgment is very important.
Rules 2, 3, and 4 are concerned with how noninvasive devices are used. Rule 2 is about
storing blood, etc.; rule 3 is about modifying body fluids; and rule 4 concerns contact with
injured skin (wound treatment for example). I think you will all appreciate the risk of storing
blood for transfusion! The bone drill is invasive so these rules do not apply (are you getting
the idea?). The orthotic insert is noninvasive but its use does not fall into any of the three rules
so it is still Class I.
Rules 5 and 6 are concerned with how invasive devices are inserted. Rule 5 concerns entry
via normal body orifices (e.g., a proctoscope); rule 6 concerns entry via a surgically produced
entry window (e.g., an arthroscope). Clearly the orthotic shoe insert does not enter an orifice;
but the drill does. Rule 6 (modified by 2007/47/EC) states:
All surgically invasive devices intended for transient use are in Class IIa unless they are:
- intended specifically to control, diagnose, monitor or correct a defect of the heart or of
the central circulatory system through direct contact with these parts of the body, in which
case they are in Class III,
- reusable surgical instruments, in which case they are in Class I,
- intended specifically for use in direct contact with the central nervous system, in which
case they are in Class III,
- intended to supply energy in the form of ionising radiation in which case they are in
Class IIb,
- intended to have a biological effect or to be wholly or mainly absorbed in which case
they are in Class IIb,
- intended to administer medicines by means of a delivery system, if this is done in a
manner that is potentially hazardous taking account of the mode of application, in which
case they are in Class IIb
Is the drill surgically invasive? Yes. Is it transient use (<60 min)? Yes. Does it fall into any
of the other five subrules? Yes. Could it be classed as a reusable surgical instrument? Well
logic suggests that drills are sharp when used the first time and get blunt after a few uses, but
they can be washed, resterilized and are reusable until blunt, broken, or bent. Our drill bit is