According to Article 2, point 6 of Regulation (EU) 2017/745, an invasive medical device is a device that, in whole or in part, penetrates inside the body through a body surface or through a body orifice. The definition is deliberately broad and thus also includes products that do not require surgical intervention. It must be distinguished from the narrower definition of a surgically invasive device in Annex VIII, Chapter I, Section 2.2, which requires penetration by means of or in conjunction with a surgical procedure, or penetration other than through a body orifice. The risk class is determined by the combination of the type of invasiveness, the access route, and the duration of application.
Types of Invasiveness and Access Routes
The Regulation practically distinguishes three constellations. First, penetration through a natural body orifice, such as in the oral cavity, ear canal, nasal cavity, gastrointestinal tract, or urogenital tract. Second, surgically invasive penetration through the body surface, including the mucous membranes of body orifices, i.e., as part of or in connection with a procedure, or penetration other than through a body orifice, which also includes needle puncture. Third, permanent residence in the body, which, according to Article 2, point 5, leads to classification as an implantable device.
In addition, there is the time axis: Annex VIII, Chapter I defines the duration of application as transient, short-term, and long-term. These categories directly affect the classification because the same type of invasiveness leads to a higher class with longer contact. The decisive factor is the uninterrupted duration of application specified by the manufacturer, not the actual residence time in individual cases.
Classification of Invasive Devices according to Annex VIII
Rule 5 concerns invasive devices in connection with body orifices that are not surgically invasive: Class I for transient use, Class IIa for short-term use, and Class IIb for long-term use, with downgrades for use in the oral cavity up to the pharynx, ear canal up to the eardrum, and nasal cavity. If such devices are intended to be connected to an active device of Class IIa, IIb, or III, they belong to Class IIa. Rule 6 generally classifies surgically invasive devices for transient use as Class IIa, with upgrades, among other things, for direct contact with the heart, central circulatory system, or central nervous system, and with the special rule that reusable surgical instruments fall into Class I.
Rule 7 deals with surgically invasive devices for short-term use, again generally Class IIa, with upgrades up to Class III for contact with the heart, central circulatory or nervous system, biological effect, complete absorption, or chemical change in the body. Rule 8 covers implantable and long-term surgically invasive devices, generally Class IIb, with numerous upgrades to Class III, for example, for active implantable devices, breast implants, surgical meshes, joint prostheses, and devices with contact to the spine.
Distinction from Surgically Invasive, Implantable, and Non-Invasive
The general term ‘invasive’ includes surgically invasive devices but is broader: a catheter inserted through a natural body orifice is invasive but not surgically invasive. Conversely, every surgically invasive device is invasive. The implantable device is a temporal specification, as it remains in the body after the procedure or remains partially inserted for at least 30 days.
Non-invasive devices are those that only come into contact with intact skin or body surface, such as dressings, electrodes on the skin, or imaging systems without body contact; Rules 1 to 4 apply to them. The activity of a device also does not constitute invasiveness, as active and invasive are independent characteristics that lead to different rule groups. If several rules are applicable, the rule leading to the higher class applies according to Annex VIII.
Relevance for clinical trials
Invasiveness shapes the benefit-risk assessment, study design, and ethical evaluation. Procedure-related risks such as bleeding, perforation, infection, and tissue damage, the experience of the user, the conditions of the study site, and suitable control strategies must be considered if blinding is not possible due to the procedure. Safety reporting must be able to distinguish between procedure-related events and product-related events to ensure the reliability of the assignment in the report.
In addition, there is the material aspect: for invasive devices, tissue contact, including its type and duration, is crucial for the biological evaluation, the results of which are incorporated into the clinical evaluation. Full-service CROs like Mediconomics support manufacturers in translating invasiveness-related risks into study plans, safety definitions, and follow-up periods, and in maintaining consistent chains of evidence between technical documentation, clinical investigation, and clinical evaluation.
Frequently Asked Questions (FAQ)
Is every invasive device surgically invasive?
No. Invasive, according to Article 2, point 6, is any device that penetrates through the body surface or through a body orifice. It is only surgically invasive if, according to Annex VIII, Chapter I, Section 2.2, it penetrates through the body surface as part of a procedure or other than through a body orifice.
What role does the duration of application play?
A decisive one. Annex VIII distinguishes between transient, short-term, and long-term application; the same type of invasiveness regularly leads to a higher risk class with longer contact.
Why are reusable surgical instruments only Class I?
Rule 6 explicitly excludes them. Their risks primarily lie in reprocessing, which is why Article 52, paragraph 7 provides for the limited involvement of a Notified Body restricted to cleaning, disinfection, sterilization, maintenance, and functional testing.
Regulatory References
- Regulation (EU) 2017/745, Article 2, point 6 – Definition of an invasive device.
- Regulation (EU) 2017/745, Annex VIII, Chapter I, Section 2.2 – Definition of a surgically invasive device.
- Regulation (EU) 2017/745, Annex VIII, Chapter III, Rules 5 to 8 – Classification of invasive devices.
- Regulation (EU) 2017/745, Article 2, point 5 – Implantable device as a temporal specification of invasiveness.
- Regulation (EU) 2017/745, Article 52, paragraph 7 – Limited involvement of the Notified Body for reusable surgical instruments.
