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Applicability of IEC 62366-1 usability to resorbable bone substitutes

#1
Dear members,
I'm on the final stage of obtaining the CE mark for a bioceramic bone substitute. In a preliminary analysis of the technical file our notified body has raised a non conformity stating "No usability file seen".
The problem is that IEC 62366-1 defines “usability” has “a characteristic of the user interface” which in turn can be defined has a way to communicate with a device. Taking into account that the medical device is a ceramic, it has no measuring functions, it does not extract or displays any kind of information, it has no ergonomic features and it is not possible to establish any kind of communication with the device (it does not receive inputs and/or gives outputs). Moreover it will be resorbed by the body and will disappear in a few months.
Thus, it is my understanding that the device has no “user interface” and by definition no “usability”. It is obvious that some "communication" is established through the labelling but those risks are under the risk management process.

Do you think IEC 62366-1 applies to 3D resorbable bone substitutes (blocks, wedges, granules)?
If so, can you provide an example?
If not, how can I explain that to the notified body? (they did not accepted the above interpretation...)

Thank you
 

indubioush

Involved In Discussions
#2
Dear members,
Do you think IEC 62366-1 applies to 3D resorbable bone substitutes (blocks, wedges, granules)?
Thank you
Of course it does. Your device comes in a package with a label, right? That is a user interface. The doctor manipulates the device and places it in the body, right? That is a user interface. You will need to determine foreseeable use errors, determine the associated risks, and mitigate them. Example: Let's say you have two devices that look similar and have similar packaging, but if you use the wrong one, there is an associated risk. Using the wrong device is a use error. You may need to make changes to your device user interface to prevent this from happening. There may be only one foreseeable use error associated with your device. You still need to document it, and if there is serious risk involved, do the formative and summative analyses required by ISO 62366.
 
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#3
The doctor manipulates the device and places it in the body, right? That is a user interface.
Thank you for replying.
With the label part I agree. Although it is already covered within the risk management process, I understand that these two standards are complementary and information will be shared between them.
But I liked the other two examples.
Wouldn't you say that using the wrong medical device is a user error and not a "use error"? IEC 62366-1 scope is "to assess and mitigate risks associated with correct use and use error, i.e., normal use.". If surgeons use a wrong device they are making an abnormal use and thus making a user error.
On the other hand, we may think that when a surgeon asks for a block, support staff can get a wedge because boxes are very similar. I can use this, but it seems so far-fetched as surgeon will so easily detect the mistake... Nevertheless I think I can understand what you meant here.
Regarding manipulation: I understand that this is an interaction (however small it may be). What I'm unable to foresee is an use error within the scope of IEC 62366-1, that is, to make a use error within the normal use of the device. The medical device is to be implanted in contact with patient bone. Which use error can the manipulation of a block, wedge or granule induce?
 

Ronen E

Problem Solver
Staff member
Super Moderator
#4
If surgeons use a wrong device they are making an abnormal use and thus making a user error.
I'm not familiar with the term "user error" as an act distinctly different from "use error". Abnormal use is a situation where users knowingly and intentionally go against instructions, so I don't think it's relevant here (it's not really an "error" in the everyday meaning).

Which use error can the manipulation of a block, wedge or granule induce?
A nice way to identify some foreseeable use errors is to go over the stated intended use (except for the contraindications part), and for each item reverse the statement to say the opposite. These "reversed items" will all be potential use errors or at least point you to some.
(The reversal of explicit contraindications in this manner will highlight abnormal use.)
 
#5
I'm not familiar with the term "user error" as an act distinctly different from "use error".
From the IEC 62366-1:
"This International Standard uses the concept of USE ERROR. The term was chosen over the more commonly used terms of “user error” or “human error” because not all errors associated with the use of a MEDICAL DEVICE are the result of oversight or carelessness on the part of the USER of the MEDICAL DEVICE. Much more commonly, USE ERRORS are the direct result of poor USER INTERFACE design."
(Note: big caps are the ones used on the IEC)

To me it seems that "user error" is an error that is imputable to the user while "use error" is imputable to the device interface.

"reversed (intended use) items" will all be potential use errors.
Our intended use is "bone substitution and repair in orthopaedic, trauma and dental surgeries". If a surgeon uses the medical device not for bone substitution it seems to me that it is knowingly and intentionally going against instructions. The medical device is similar to bone (resistance and structure) and it has nothing that can be confused with any other kind of human tissue. It is very hard to think on use errors induced by the medical device...
I can however reverse some of the "how to apply" statements and get things like "do not check expiry date"... So, thank you for that idea. (y)
 

Tidge

Involved In Discussions
#6
I'm not familiar with the term "user error" as an act distinctly different from "use error". Abnormal use is a situation where users knowingly and intentionally go against instructions, so I don't think it's relevant here (it's not really an "error" in the everyday meaning).
I'm sure Ronen is aware of this, but this comment is for others who may not be aware: There has been a strong push (last ten years? maybe longer) to explicitly NOT use the term 'user error' as this has several negative implications. One negative implication is that complaints about the medical device could be blamed on the user/patient when it would be possible to reduce the risk of the device by considering the circumstances of use and the types of users. Including instructions for use (IFU) is not recognized as means of reducing risk. I believe in the modern parlance, IFU can still be factored into a risk-benefit acceptability analysis even if it is not considered legitimate to reduce the risk of a device with IFU.

Ultimately, the goal of a recognized/regulated medical device manufacturer is to market safe and effective medical devices. The scenarios of use of a device can contribute to the risk profile, so the NB may have felt that the absence of a usability file was evidence of an incomplete risk analysis.

I have found that a practical approach to beginning a usability analysis (for design teams which have never done this before and/or don't have a prescribed/mature methodology) is to start backwards from what are the sort of complaints that your team are tempted to brush off as 'user (sic) errors'. The trick is to resist simply casting aside such complaints and to think about how you (as the manufacturer) can reduce risks related to these scenarios. This is a very crude approach, but it helps get the ball rolling.
 

indubioush

Involved In Discussions
#7
It is also helpful to do a use FMEA (UFMEA) in which you determine the foreseeable use errors associated with each task performed by the user. You say that some situations are "far-fetched." Instead of disregarding these far-fetched situations, you should document them in an FMEA and record your estimated low probability of occurrence. The resulting risk will also be low. This proves to your Notified Body that you have done your due diligence.
 

Tobias_HF

Starting to get Involved
#8
Hi
I`d like to point out that the "accompanying documentation" or IFU / manuals... is also part of the user interface. This also includes the training, which the users will receive, to work with the device.
@Ventura so from a NB persepctive they might ask you for a
- formative study of the IFU and training
- summative study of IFU and training. This might be done with an actual use study, in my opinion.

As you need to build your IFU based on your user profile / use spec, and address the most likely / severe use errors, a uFMEA (as suggested) will definitely help.
 
#9
Thank you all for the inputs.
I've decided to treat labelling as the interface and make several tests like type and size of fonts in order to access legibility as well as asking several physicians to read and comment on the sentences used to test for misleading descriptions, etc.
 

Tobias_HF

Starting to get Involved
#10
Thank you all for the inputs.
I've decided to treat labelling as the interface and make several tests like type and size of fonts in order to access legibility as well as asking several physicians to read and comment on the sentences used to test for misleading descriptions, etc.
Thats definitely a good start.
What might help also is a "cloze test" with parts of your IFU. Well basically you select a couple of paragraphs that are "typical" for your IFU, and delete words according to the cloze method. And then ask the users to fill the blanks in.
In a formative test, this gives you a good indication if your writing style is understandable for the users.
Font size / legibility I would typically exclude, as long as you keep a tandard in mind, should be good.
The tricky part is writing for users, when the author is not a user...
 
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