Common Obstacles to a Great Medical Literature Review Under the EU MDR

By Published On: August 15th, 2023Categories: EU MDR, Literature Search and Literature Review

Medical device literature reviews are mandatory for any clinical evaluation under the EU MDR.

More importantly, they are essential for medical device manufacturers looking to establish or confirm their medical devices’ benefit/risk profile through clinical evaluation and clinical evidence.
Most medical device manufacturers can only produce clinical investigations if they manufacture higher-risk devices.
Clinical investigations are expensive, complicated to set up, complicated to get approved, and straight-up unnecessary for many devices.
So those medical device manufacturers need clinical data from other sources for their clinical evaluation.
This is where the literature review shines.
Literature reviews are perfect for evaluating the safety and performance of the medical device in question and similar devices and alternative therapies and treatments.
But what makes a great clinical evaluation literature review?
And what are the most common obstacles you’ll have to overcome to get there?

A systematic process for gathering clinical data

The most critical aspect of any medical device literature review, regardless of the clinical evaluation and type and risk classification of the medical device, is that it is performed systematically and organized.
It doesn’t matter how much outstanding clinical data you find for your medical device during your search – you will get your clinical evaluation into trouble with the notified body if there are inconsistencies in your planning.
For example, you want to search for safety and performance for three similar devices.
You establish the search term for two devices as the device name.
But for the third medical device, you use the manufacturer name as the search term.
Or, you search the manufacturer name for all three devices, but for one device, you also search the distributor/contract manufacturer name because the device is more commonly known under that entity name in a large market, such as the US.
Both of these examples highlight a process that needs to be more systematic.
You might know there won’t be any results if you search for the device name.
You’ve probably done these searches millions of times.
But you still need to show your notified body.
Establishing a systematic process where everything is done the same way every time will avoid problems with the regulatory authorities. More importantly, you will be sure you get the right results, the appropriate amount of clinical evidence, and that your literature search is as thorough as can be.

Literature search protocol for medical devices

Similarly to the systematic process, getting the literature search protocol right is the best way to ensure you get your literature review out of the gate correctly.
The more detailed you can make your literature review protocol, the better.
Like a recipe for your searches, an appropriate literature search protocol makes the subsequent literature search a walk in the park.
Stuff everything you can in there – search terms, inclusion/exclusion criteria, claims and benefits you are evaluating, templates for search results tables and data appraisal, who will be doing the searches and when, and anything else you can think of.
You can always document any changes you make to the literature search protocol later.
The important thing is getting it down on paper first, so you have a thorough and complete work plan.
The literature search protocol is also the perfect place to spot errors or inappropriate literature search plans for your clinical evaluation – when everything is gathered in one place, it is much easier to spot if your literature search terms are inconsistent or whether your exclusion criteria actually make sense.

Medical device equivalence

Many medical device manufacturer dream of claiming equivalence between their device and another on the market. Especially manufacturers coming from the US market where equivalence is the foundation of the 510(k) clearance scheme.
It seems logical that if you can find a device that is problem-free and doesn’t have any safety issues, you can claim that your device is equivalent to that device, and you will speed up your approval or clinical evaluation process.
However, equivalence in the EU differs from that for the 510(k).
Medical devices must be technologically, biologically, and clinically equivalent.
Even the most negligible differences in intended use, technology applied, or clinical indications will disqualify devices from being equivalent to one another.
Claiming equivalence in the EU is exceptionally difficult unless manufacturers own, or are otherwise related to, or subsidiaries of, the devices with which they want to claim equivalence.
We do not recommend claiming equivalence for clinical evaluations under the EU MDR – it is just too complicated.
Once you claim equivalence, the notified body will scrutinize your equivalence assessment which can significantly delay timelines.
They will often find faults with the equivalent device and reject the claim.
Using similar devices for your literature search and review is much easier, as any device with similar indications for use and technology can be applied.

Document your thought process

People can’t read thoughts, so documenting your thought process is the easiest way to ensure your clinical evaluation report is clear.
You cannot assume anyone knows anything, even when it might seem obvious.

Experience with clinical evaluation

With all that being said, the most common obstacle medical device manufacturers face when performing medical device literature reviews and clinical evaluation reports is more experience.
Literature reviews might seem simple from the outside, but many decisions are involved in almost every step of the evaluation.
Likewise, many aspects of the literature review require finesse and a deep understanding of clinical data, its relevance, and how to appraise it.
Unfortunately, literature reviews cannot be learned through online tutorials and downloading free templates. They help, of course, but the search and review itself requires experience.
Most regulatory professionals are not sufficiently versed in handling clinical data and formulating an appropriate evaluation of the benefit-risk profile of medical devices.
Even more importantly, most regulatory professionals are hard-pressed for time, to begin with, and will need more resources and time to train in clinical evaluations.
For many medical device manufacturers, hiring external consultants is the best option for presenting a great literature review to the notified body.
Consultants or medical writers will also have vast arrays of experience in notified body feedback and can rectify any issues or non-conformities quickly and painlessly.

Frequently asked questions

How can I optimize my literature searches?

The simplest way to optimize searches is to do preliminary searches before you have even written your literature review protocol. It’s a great way to estimate the amount of clinical data you can get, broaden or narrow search terms, and check your inclusion and exclusion criteria. Likewise, a preliminary search can help you check the relevance of your search terms and keywords and adjust your search strategy before starting.

How much clinical data is enough?

Sadly, there is no definitive answer. The appropriate amount of clinical data is the data available to adequately demonstrate the acceptability of the risk-benefit profile of your device.

How many databases should I search? 

Generally, 3-5 literature databases and 2-4 adverse event databases are sufficient. We recommend choosing literature databases and adverse event databases that account for different markets and sources to ensure diversity in your literature reviews. 

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