(78 days)
- Increasing local blood circulation
- Edema reduction
The geko™ W-2 neuromuscular stimulator is a disposable, fully integrated unit composed of a constant current pulse generator with embedded software, a lithium coin-cell battery enclosed in an over-molded plastic casing, and a silver electrode with a hydrogel coating which provides a means of attachment of the device and electrical contact with the patient. Two buttons are used to control the On/Off function and increase or decrease the intensity level of the device output, which is achieved through choosing one of 10 stimulus settings. The geko™ W-2 is applied so that the electrodes lie over the common peroneal nerve behind the knee. Stimulation of the common peroneal nerve causes contraction of the calf muscles through the direct activation of the motor neurons, resulting in increased blood flow. The pulse rate is fixed at a frequency of 1 Hz and is used to isometrically stimulate the calf and foot muscles with a cadence and energy similar to that of walking. Each geko™ W-2 provides two 6-hour treatments with a 6 hour minimum rest period between treatments. Two optional accessories are available to hold the geko W-2 in place during treatment, if needed: a knee strap and an adhesive tape.
The geko™ W-2 device is a neuromuscular stimulator intended for increasing local blood circulation and edema reduction. The following information outlines its acceptance criteria and the study conducted to demonstrate equivalence to a predicate device.
1. Table of Acceptance Criteria and Reported Device Performance
The FDA 510(k) summary focuses on demonstrating substantial equivalence to a predicate device (geko™ Plus R-2, K180082) rather than defining specific numerical acceptance criteria for clinical performance. Instead, acceptance is based on the device meeting established performance standards for safety and fundamental operational characteristics, and showing that any differences from the predicate do not raise new questions of safety or effectiveness.
| Parameter | Acceptance Criteria (Demonstrated) | Reported Device Performance (geko™ W-2) |
|---|---|---|
| Biocompatibility | Device materials in contact with intact skin must be biocompatible according to ISO 10993-5 (Cytotoxicity) and ISO 10993-10 (Sensitization and Irritation). The new hydrogel (KM40A) must meet these standards. | KM40A hydrogel demonstrated biocompatibility for intended use contact. |
| Electrical Safety | Must comply with relevant electrical safety standards. (Implied: No changes from predicate, hence predicate compliance assumed to cover the geko™ W-2). | Not tested, as there are no changes in electrical hardware compared to the predicate (geko™ Plus R-2). |
| Electromagnetic Compatibility (EMC) | Must comply with IEC 60601-1-2:2014. This includes requirements for a non-rechargeable, battery-powered medical device regarding electromagnetic disturbances. | All tests were passed based on IEC 60601-1-2:2014, with testing conducted in continuous operating mode at the highest stimulus setting. |
| Hardware/Firmware Functionality | The device's hardware and firmware must function correctly, including accurate output waveform characteristics across various loads and overall device functionality. | All tests were passed, verifying output waveform characteristics via oscilloscope tracings (at 500Ω, 2kΩ, and 10kΩ) and validating all geko™ W-2 hardware and firmware functionality. |
| Performance (Durability/Adhesion) | Device durability must be maintained over multiple uses, including resistance to application/removal cycles and adequate adhesion for intended use. | All test samples passed all repeat test cases for: 1) device operation when applied and removed from a test substrate 100 times; and 2) device adhesion when applied and removed for a total of 10 use cycles. |
| Indications for Use Consistency | The device's indications for use must be a subset of or equivalent to the predicate device, or any differences must be justified and not raise new safety or effectiveness concerns. Specifically, for increasing local blood circulation and edema reduction. Must not be indicated for prevention of venous thrombosis due to shorter treatment duration. | The indications for use (increasing local blood circulation and edema reduction) are a subset of the predicate, as the geko™ W-2 is not indicated for venous thrombosis prevention due to its limited 6-hour treatment duration. Otherwise, the indications are consistent. |
| Technical Specifications (Comparison to Predicate) | Any differences in technical specifications (e.g., number of stimulus levels, treatment duration, hydrogel type) must be adequately explained and supported, and not compromise safety or effectiveness. | The geko™ W-2 has 10 stimulus levels (vs. 8 in predicate, with two lower pulse widths added), two 6-hour treatments with a 6-hour rest (vs. single 30-hour run time), and uses KM40A hydrogel (vs. KM10T). These changes are justified for patient comfort/sensitivity. |
2. Sample Size and Data Provenance for Test Set, and Training Set Sample Size
The document primarily describes design validation activities rather than a study with a traditional "test set" for clinical performance. The focus is on engineering verification and validation.
- Test Set Sample Size: Not explicitly stated as a separate clinical test set. The validation activities involve discrete hardware, software, and material tests. For example, durability testing involved multiple (100 and 10) application/removal cycles on test samples. Biocompatibility testing typically involves a set number of samples for in vitro and in vivo assessments as per ISO standards but is not quantified in this summary.
- Data Provenance (Test Set): Data is generated through internal laboratory testing and external accredited lab testing (e.g., for biocompatibility and EMC) conducted as part of the device's design validation. The country of origin for these tests is not specified, but the submitter is Firstkind Limited in the UK.
- Sample Size for Training Set: This device is a hardware neuromuscular stimulator, not an AI/ML-based algorithm. Therefore, there is no "training set" in the context of machine learning.
3. Number of Experts and Qualifications for Ground Truth Establishment (Test Set)
This is not applicable to the information provided. The ground truth for the engineering tests is based on established scientific principles, medical device standards (e.g., ISO, IEC), and the functional specifications of the device. Expert clinicians are not typically involved in establishing "ground truth" for electrical safety or biocompatibility tests.
4. Adjudication Method (Test Set)
Not applicable. The validation activities are based on meeting pre-defined objective criteria in engineering and material performance tests, not on expert adjudication of subjective outcomes.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
Not applicable. This device is an electrical stimulator, not an imaging or diagnostic AI device. There is no AI component that assists human readers.
6. Standalone (Algorithm Only) Performance Study
Not applicable. This device is a physical neuromuscular stimulator. It is not an algorithm that operates in a standalone manner.
7. Type of Ground Truth Used (for Test Set)
The "ground truth" for the validation activities are:
- Objective Engineering Standards: Compliance with ISO (biocompatibility), IEC (EMC), and internal validated specifications for electrical characteristics (waveform, current, voltage, pulse widths, frequency), software functionality, and mechanical durability.
- Predicate Device Specifications: The predicate device's established safe and effective technical parameters serve as a baseline for demonstrating substantial equivalence for the core functional aspects.
8. Sample Size for Training Set
As mentioned in point 2, this is not an AI/ML device, so there is no "training set."
9. How Ground Truth for Training Set was Established
Not applicable, as there is no training set.
§ 890.5850 Powered muscle stimulator.
(a)
Identification. A powered muscle stimulator is an electrically powered device intended for medical purposes that repeatedly contracts muscles by passing electrical currents through electrodes contacting the affected body area.(b)
Classification. Class II (performance standards).