Electrosurgery Active Accessory Q: 60601-2-18 applicability? "Applied Parts"?

[Tidge]

I'm reviewing a test plan for monopolar ACTIVE ACCESSORY (with the ACTIVE ELECTRODE)... so not an ESU, not a NEUTRAL ELECTRODE, neither a power cable nor control mechanism. The active accessory will have no (electrical) energy within it except that provided by an ESU. This is new to me, so I have questions.

The particular IEC 60601-2-2:2017 A1:2023 is applicable, specifically it looks like this testing is appropriate:

• 201.8.8.3.101 Active Accessory insulation
• 201.8.8.3.102 Active Accessory HF leakage
• 201.8.8.3.103 Active Accessory HF dielectric strength
• 201.8.8.3.104 Active Accessory mains frequency dielectric strength

Per the FDA Premarket Notification (510(k)) Submissions for Electrosurgical Devices for General Surgery Guidance (March 2020) references IEC 60601-2-18:2009 in a couple of places:

XII. Electrical Safety and Electromagnetic Compatibility:
Additionally, endoscopic/laparoscopic electrosurgical instruments should demonstrate compliance with IEC 60601-2-18, Medical electrical equipment – Part 2-18: Particular requirements for the basic safety and essential performance of endoscopic equipment. [...]
In addressing EMC, please be aware that according to IEC 60601-2-2, high frequency surgical instruments are intentional emitters of electromagnetic energy and, therefore, emissions testing to IEC 60601-1-2 is only needed for power generators in the idle state (i.e., powered on but surgical energy not activated). However, even during idle testing, particular attention should be paid to the effects of connected accessories and instruments, such as cord length (for resonant frequency) and instruments that contain electronics. For instruments with different cord lengths, connection types, or electronic components, it may not be appropriate to use a single “representative” instrument model for testing purposes.
If your submission is for a specific component of the electrosurgical device, you are still expected to evaluate your component while connected to other components of the electrosurgical device system. This should be performed consistent with how

Question: Aside from some consideration in the risk management file, is there any sort of OE (i.e. any meaningful test) for a monopolar accessory to demonstrate "consideration"? As a practical matter, there is a wide and deep pool of ESU that such a device could be connected to.

As an aside, the test plan includes testing for compliance to IEC 60601-1-2... Any suggestions what that would actually look like? I'm thinking that these sorts of accessories don't all of a sudden become troublesome antennae (in the 60601-1-2 sense) simply when connected... but this is new to me. If the ACTIVE ACCESSORY (not the cable) is covered in the ad hoc examples of Annex BD of 60601-2-2... I missed it. Is it that I am supposed to imagine a test where my non-energized ACTIVE ACCESSORY is (potentially) being energized by another, separate active acessory? If so, I feel like I can "risk amanagement file" my way out of such a circumstance.

The FDA guidance is equally clear and cloudy in XI. Performance Data E. System Testing. In particular:

1. Thermal Effects on Tissue
Per 60601-2-2 clause 201.11.1.2.1 APPLIED PARTS intended to supply heat to a PATIENT: ACTIVE ELECTRODES are considered to be APPLIED PARTS intended to supply heat to a PATIENT as part of their intended clinical effect (CUTTING and COAGULATION). Disclosure of temperatures and clinical effects is not required.... so this looks like the submission guidance asking for something that the standard explicitly doesn't want. I think a reasonable plan for submission (based on later text of the guidance doc) would be to do a like-for-like comparison on a variety of ex vivo animal tissues using representative modes of operation, yet I don't know how hard the regulatory reviewers would look at these analyses. Any suggestions? (I don't want to bring this up in a presub being completely uninformed!)

also 4. Capacitive Coupling
If the proposed device design includes monopolar electrosurgical electrodes for use in minimally invasive surgery, we recommend you test for active coupling resistance between the subject device and a conductive cannula/trocar device under simulated normal use conditions. This testing should be performed as recommended by the currently FDA-recognized versions of IEC 60601-2-18, Medical electrical equipment – Part 2-18: Particular requirements for the basic safety and essential performance of endoscopic equipment and IEC 60601-2-2. For electrosurgical electrodes and accessories, we also recommend you address the risks of leakage currents through insulation as well as capacitive coupling with other surgical equipment (e.g., pulse oximeter probes, invasive blood pressure transducers, temperature probes camera systems) as a part of your risk management process (e.g., cross-coupling between different HF patient circuits).

Question: Is there any testing (supplimental or otherwise) in 60601-2-18 that is relevant for a device already being tested to 60601-2-2's 201.8.8.3.101 through 201.8.8.3.104? Obviously I don't want an ACTIVE ACCESSORY charging up a trocar, or anything else in the area (or patient!) that could be contacting a patient or user... I worry that I could be missing an important test in this area.

Another place 60601-2-18 is mentioned in the guidance:

XIV. Labeling
This appears pretty straightforward. but I have some confusion on the B. Device Labels section:
In your submission, we recommend that you provide illustrations to show how each component of your device is labeled to demonstrate that all controls, switches, and connections (including those for hand switched active electrodes and foot switches) are clearly, concisely, and permanently labeled to identify their function and other important information (e.g., Type BF Applied Part).

The nature of the device has me confused about whether or not the (monopolar) ACTIVE ACCESSORY (which fits the definition of an APPLIED PART) requires any of the following?

• Testing beyond what is identified in 60601-2-2's 201.8.8.3.101 through 201.8.8.3.104 (I'm associating some of those tests with the conditions where the instrument NON-electrode portions are in contact with a patient and/or trocar, wether or not the accessory is energized)
• 60601-2-2 has this addition via clause 201.7.2.10 for APPLIED PARTS: The relevant symbols required for marking DEFIBRILLATION-PROOF APPLIED PARTS shall be attached to the front panel, but are not required on the APPLIED PARTS. Should the active accessory be labeled as a BF (or CF) part?... and if so what testing specifically demonstrates conformance?
  

 

[Search&Comply]

1. I suggest checking with your NRTL on applicability of IEC60601-2-18, which is an Endoscope standard, to your device. The test lab will not issue an IEC 60601-2-18 test report for a device that is not an endoscope. The only FDA recommended test which normally applies for laparoscopic electrosurgical devices is Capacitive Coupling.
2. Reviewers will go over your Thermal Effects on Tissue test report in detail. You need to determine worst-case generator modes (Cut, Coag) and select low, medium and high power levels to create coagulation zones on the three tissue types described in the Guidance. Follow the recommendations in that section explicitly for your protocol. The comparison must be between the cutting or coagulation performance of the selected predicate and your device. Using a histology lab for tissue analysis is expensive and time consuming, however FDA allows using 'measurement under magnification' to analyze the width and depth of coagulation zones. ImageJ is a popular software available for free download from the NIH. This is not a Pass-Fail test. FDA is looking for data comparison showing your device can effectively treat tissue.
3. Capacitive Coupling test reference to IEC 60601-2-18 is mainly for one clause and the test equipment layout figure. If your device is not an endoscope, the rest of the standard will not apply. Rely on IEC 60601-2-2 for pertinent information.
4. Labeling includes your Instructions for Use. Find IFU examples of either your predicate or similar devices online for reference. A Type BF or CF indication depends on the leakage current of the power supply in the electrosurgical generator you identify for use with your device. Again, your NRTL can specify these classifications and applicable tests.

 

[Tidge]

w.r.t. BF/CF, since 60601-2-2 explicitly calls out that the APPLIED PARTS don't need to be labeled (as BF/CF), I'm not going to sweat that. While I don't think anyone would make the following argument this way: Since the active electrodes for electrosurgery are literally used to deliver harmful energy (in a controlled way) to a patient... it would be a tortured sort of argument to pretend that they have a risk profile commensurate with other types of medical electrical devices such that the concerns for BF/CF for those would be applicable to ACTIVE ELECTRODES.

As for the 60601-2-18... having reviewed both -2-2 and -2-18 (and their informative annexes), and communicating with a NRTL... I'm convinced that this part of the guidance (for electrodes) is a sort of "historical" leftover in the FDA guidance, as the basic safety for active electrodes in -2-2 is more-or-less what the proposed NRTL test is for "-2-18". If I had to guess: There were probably a number of patient injuries related to coupling between active electrodes and endoscopes... speculation follows: I think injuries are more likely to occur from direct coupling between the instruments (including possible intentional touching if the surgeon touched the electrode to the scope to cool the electrode)... but that because capacitive coupling is real, and an error-free surgery would be the active electrode only being used on tissue, that there was a confluence of factors that got "capacitive coupling for -2-18" called out in the guidance. I simply don't believe that an active electrode that passes the basic safety tests of -2-2 would ever capacitively couple to an endoscope.