The geko™ T-3 Neuromuscular Stimulator (geko™ T-3) is single-patient use and disposable, with fully integrated electronics composed of a constant current pulse generator with embedded software and a lithium-ion battery enclosed in a 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 changes in the delivered pulse width. The geko™ T-3 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 stimulus intensity varies with the pulse width, which can be set to one of 11 levels: 35, 50, 70, 100, 140, 200 or 280 at 27 mA; 280 or 400 at 38 mA; and 400 or 560 at 54 mA. The asymmetric biphasic waveform results in a net charge of zero to the patient during each pulse cycle. 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.

AI/ML Overview

Here's a breakdown of the acceptance criteria and the study proving the device meets them, based on the provided FDA 510(k) summary for the geko™ T-3 Neuromuscular Stimulator:

This document is a premarket notification (510(k)) submission, which aims to demonstrate that a new medical device is substantially equivalent to a legally marketed predicate device. For devices seeking 510(k) clearance, the "acceptance criteria" are primarily established by showing that the new device has the same indications for use and similar technological characteristics to a predicate device, and that any differences do not raise new questions of safety and effectiveness.

The core "study" proving the device meets the acceptance criteria in a 510(k) context is a comparative analysis with predicate devices and verification/validation testing of the device's adherence to relevant performance and safety standards.

1. Table of Acceptance Criteria and Reported Device Performance

For the geko™ T-3 Neuromuscular Stimulator, the "acceptance criteria" are largely met by demonstrating substantial equivalence to its predicate devices (geko™ T-2 and geko™ Plus R-2). The reported device performance is shown by its adherence to technical specifications and compliance with recognized electrical safety and electromagnetic compatibility standards.

Acceptance Criteria (Demonstrated Equivalence to Predicate Devices)	Reported Device Performance (geko™ T-3)
Indications for Use:	Same Indications for Use:
- Increasing local blood circulation	- Increasing local blood circulation
- Immediate post-surgical stimulation of the calf muscles to prevent venous thrombosis	- Immediate post-surgical stimulation of the calf muscles to prevent venous thrombosis
- Edema reduction	- Edema reduction
Technological Characteristics:	Demonstrated Characteristics:
- Number of output modes: 1	- 1
- Number of output channels: 1	- 1
- Method of stimulus regulation: Current regulated	- Current regulated
- Microprocessor controlled? Yes	- Yes
- Automatic overload trip: Yes	- Yes
- Automatic no-load trip: Yes	- Yes
- Automatic shut-off: Yes	- Yes
- Patient over-ride control: Yes	- Yes
- Indicator displays (On/Off, Low battery, Stimulus level)	- Yes (device switches off for Low battery)
- Waveform: Asymmetrical, biphasic, rectangular waveform with charge balancing second phase	- Asymmetrical, biphasic, rectangular waveform with charge balancing second phase (uses different method of charge balancing, but net charge remains essentially zero)
- Maximum output voltage: (Ranges depend on impedance; similar or within range of predicates)	- 27.0 V @ 500 Ω, 108 V @ 2000 Ω, 255 V @ 10,000 Ω (All voltages ±10%) - Matches geko™ Plus R-2 and encompasses geko™ T-2
- Maximum output current: (Ranges depend on impedance; similar or within range of predicates)	- 54 mA @ 500 Ω, 54 mA @ 2000 Ω, 54 mA @ 10,000 Ω (All currents ±15%) - Matches geko™ Plus R-2 and encompasses geko™ T-2
- Pulse widths ($\mu$s): (Ranges similar or encompassing predicates)	- 35, 50, 70, 100, 140, 200, 280 (@ 27 mA); 280, 400 (@ 38 mA); 400, 560 (@ 54 mA) - More stimulus levels (11) available; includes one additional shorter pulse width (35 µs) not on predicates, but current levels are within predicate ranges.
- Frequency: 1 Hz, fixed	- 1 Hz, fixed
- Net charge: 0 µC at 500Ω, capacitor coupled (for predicates)	- +/- 0.1 µC at 500Ω, phase balancing (demonstrates essential zero charge)
- Maximum phase charge: (Similar or within range of predicates)	- 40 µC at 500 Ω - Matches geko™ Plus R-2 and encompasses geko™ T-2
- Maximum current density: (Similar or within range of predicates)	- 13.3 mA/cm² - Matches geko™ Plus R-2 and encompasses geko™ T-2
- Maximum power density: (Similar or within range of predicates)	- 0.000088 W/cm² - Matches geko™ Plus R-2 and encompasses geko™ T-2
- Timer range: 1800 min max (30 hr run time)	- 1800 min max (30 hr run time)
- Power source: One 3V lithium coin cell	- One 3V lithium coin cell
- Weight: 10 g	- 10 g
- Dimensions: 7.8" x 1.2" x 0.4"	- 7.8" x 1.2" x 0.4"
- Patient contacting materials: Hydrogel (KM10T)	- Hydrogel (KM10T)
- Housing material: Polypropylene Plastic injection molding	- Polypropylene Plastic injection molding
Safety and Performance Standards Compliance:	Demonstrated Compliance:
- Electrical Safety (e.g., IEC 60601-1)	- Certified to comply with IEC 60601-1:2005 +A1(2012)
- Electromagnetic Compatibility (e.g., EN 60601-1-2)	- Certified to comply with EN 60601-1-2:2015
- Specific Stimulator Standards (e.g., IEC 60601-2-10)	- Certified to comply with IEC 60601-2-10:2012 +A1(2016)
- Home Healthcare Environment (e.g., IEC 60601-1-11)	- Certified to comply with IEC 60601-1-11:2015
- Correct functioning of hardware/firmware, accurate output waveform characteristics	- Verified via oscilloscope output tracings at 500Ω, 2kΩ, and 10kΩ; All hardware and firmware functionality validated.

Study Description (for 510(k) Substantial Equivalence)

The "study" in this context is a series of verification and validation activities conducted by the manufacturer to demonstrate substantial equivalence to predicate devices and adherence to regulatory standards.

2. Sample Size Used for the Test Set and Data Provenance:

Sample Size: Not applicable in the conventional sense of a clinical trial patient sample size. For this 510(k) submission, the "test set" consisted of the geko™ T-3 device itself and its components. The document describes verification and validation testing (e.g., electrical safety, EMC, hardware/firmware functionality). The sample size for these tests refers to the number of devices or components tested to ensure they meet specifications and standards. This typically involves testing a sufficient number of units to ensure reliability and compliance, though the exact number of units tested is not specified in this summary.
Data Provenance: The testing was conducted as part of the company's design change procedures. The manufacturer, Firstkind Limited, is based in High Wycombe, UK. This suggests the testing data originates from the UK. The document doesn't specify if the testing was retrospective or prospective, but typically design verification and validation testing is prospective to the submission.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts:

This type of information is generally not required for a 510(k) submission that relies on technical equivalence and performance testing rather than clinical data interpretations by experts (like for imaging AI).
The "ground truth" here is adherence to engineering specifications and international safety standards. The "experts" would be the certified testing bodies and internal quality/regulatory engineers with expertise in electrical engineering, medical device standards, and quality management systems (e.g., IEC standards, ISO 13485). Their qualifications are typically implied by their accreditation and certifications to perform such tests.

4. Adjudication Method for the Test Set:

Not applicable as this is not a study involving human readers or interpretations of complex data like medical images. The "adjudication" is compliance with documented test procedures and objective measurements against established engineering and safety standards.

5. If a Multi Reader Multi Case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:

No, an MRMC comparative effectiveness study was not done. This device is a neuromuscular stimulator for physical indications, not an AI imaging diagnostic tool. Therefore, MRMC studies and human reader improvement metrics are not relevant to this submission.

6. If a standalone (i.e. algorithm only without human-in-the loop performance) was done:

This concept is typically relevant for AI/ML algorithms. For this device, the "standalone" performance refers to the device's ability to operate according to its specifications and comply with safety standards independent of human intervention in its function. The Hardware/Firmware Testing section mentions "Verification of output waveform characteristics via oscilloscope output tracings" and "Validation of all geko™ T-3 hardware and firmware functionality." This is essentially "standalone performance" testing for a hardware device with embedded software.

7. The type of ground truth used:

The ground truth for the device's "performance" and "safety" is established by:
- Engineering Specifications: The defined output parameters (current, voltage, pulse width, frequency, net charge, etc.) and physical characteristics.
- International Standards: Compliance with recognized medical electrical equipment (IEC 60601-1, IEC 60601-2-10, IEC 60601-1-11) and electromagnetic compatibility (EN 60601-1-2) standards.
- Comparison to Predicate Devices: The established safe and effective design and performance of the legally marketed predicate devices (geko™ T-2 and geko™ Plus R-2).

8. The sample size for the training set:

Not applicable. This device is hardware with embedded software, not an AI/ML device that requires a "training set" of data in the common sense for model development. The software capabilities are validated through traditional software verification and validation activities (e.g., unit testing, integration testing, system testing).

9. How the ground truth for the training set was established:

Not applicable for AI/ML training data. Any "ground truth" for the device's design and embedded software was established through engineering design principles, risk analysis, and adherence to performance specifications and relevant international standards.

Summary

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Image /page/0/Picture/0 description: The image shows the logo of the U.S. Food and Drug Administration (FDA). On the left is the Department of Health & Human Services logo. To the right of that is the FDA logo, which consists of the letters "FDA" in a blue square, followed by the words "U.S. FOOD & DRUG" in blue, with the word "ADMINISTRATION" underneath in a smaller font.

Mav 23, 2018

Firstkind Limited % Sheila Hemeon-Heyer President Heyer Regulatory Solutions LLC 125 Cherry Lane Amherst, Massachusetts 01002

Re: K181059

Trade/Device Name: geko™ T-3 Neuromuscular Stimulator Regulation Number: 21 CFR 890.5850 Regulation Name: Powered muscle stimulator Regulatory Class: Class II Product Code: IPF Dated: April 23, 2018 Received: April 23, 2018

Dear Sheila Hemeon-Heyer:

We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.

Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part

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801); medical device reporting of medical device-related adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.

For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/) and CDRH Learn (http://www.fda.gov/Training/CDRHLearn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (http://www.fda.gov/DICE) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).

Sincerely,

Vivek J. Pinto -S

for Carlos L. Peña, PhD, MS Director Division of Neurological and Physical Medicine Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

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Indications for Use

510(k) Number (if known) K181059

Device Name

geko™ T-3 Neuromuscular Stimulator

Indications for Use (Describe)

Increasing local blood circulation
Immediate post-surgical stimulation of the calf muscles to prevent venous thrombosis
Edema reduction

Type of Use (Select one or both, as applicable)
X Prescription Use (Part 21 CFR 801 Subpart D)	Over-The-Counter Use (21 CFR 801 Subpart C)

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510(k) Summarv

This summary of 510(k) safety and effectiveness information is being submitted in accordance with the requirements of 21 CFR 807.92.

A. Submitter:	Firstkind LimitedHawk HousePeregrine Business ParkHigh Wycombe, UKHP13 7DL
Contact:	Neil BuckleyHead of Quality and Regulatory Affair
Tel:Email:	+44 (0) 845 2222 921neil.buckley@firstkindmedical.com

B. Date Prepared: May 23, 2018

Device Name and Classification Information: C.

Trade Name:	geko™ T-3 Neuromuscular Stimulators
Classification Name:	Stimulator, Muscle, Powered
Product Code, CFR:	IPF, 21 CFR 890.5850
Panel code:	89
Class:	II

D. Predicate Devices: K180082 for geko™ T-2 and geko™ Plus R-2

Device Description: ய்

The geko™ T-3 Neuromuscular Stimulator (geko™ T-3) is single-patient use and disposable, with fully integrated electronics composed of a constant current pulse generator with embedded software and a lithium-ion battery enclosed in a 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 changes in the delivered pulse width. The geko™ T-3 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 stimulus intensity varies with the pulse width, which can be set to one of 11 levels: 35, 50, 70, 100, 140, 200 or 280 @ 27 mA; 280 or 400 @ 38 mA; and 400 or 560 @ 54 mA. The asymmetric

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biphasic waveform results in a net charge of zero to the patient during each pulse cycle. 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.

F. Indications for Use:

Increasing local blood circulation ●
Immediate post-surgical stimulation of the calf muscles to prevent venous . thrombosis
Edema reduction ●

G. Technical Comparison with the Predicate Device and Discussion of Differences

The geko™ T-3 Neuromuscular Stimulator device incorporates the stimulus output levels of the geko™ T-2 and geko™ Pus R-2 into a single device.

Parameter	Predicategeko™ T-2	Predicategeko™ Plus R-2	Proposedgeko™ T-3
Indications for use	• Increasing local blood circulation• Immediate post-surgical stimulation of calf muscles to prevent venous thrombosis• Edema reduction	• Increasing local blood circulation• Immediate post-surgical stimulation of calf muscles to prevent venous thrombosis• Edema reduction	• Increasing local blood circulation• Immediate post-surgical stimulation of calf muscles to prevent venous thrombosis• Edema reduction
Number of output modes	1	1	1
Number of output channels	1	1	1
- Synchronous or alternating?- Method of channel isolation?	N/A	N/A	N/A
Method of stimulus regulation	Current regulated	Current regulated	Current regulated
Microprocessor controlled?	Yes	Yes	Yes
Automatic overload trip	Yes	Yes	Yes
Parameter	Predicategeko™ T-2	Predicategeko ™ Plus R-2	Proposedgeko™ T-3
Automatic no-loadtrip	Yes	Yes	Yes
Automatic shut-off	Yes	Yes	Yes
Patient over-ridecontrol	Yes	Yes	Yes
Indicator displays- On/Off status
- Low battery	Yes	Yes	Yes
- Stimulus level	Yes (device switches off)	Yes (device switches off)	Yes (device switches off)
	Yes. Stimulation level(pulse width) is indicatedby the number of timesthe LED flashes insequence, e.g., a singleflash for Level 1 (50$\u03bcs$ /27 mA) up to 7flashes for Level 7 (400$\u03bcs$ /27 mA)	Yes. Stimulation level(pulse width) is indicatedby the number of timesthe LED flashes insequence, e.g., a singleflash for Level 1 (50$\u03bcs$ /54 mA) up to 8 flashesfor Level 8 (560 $\u03bcs$ /54mA).	Yes. Stimulation level(pulse width) is indicatedby the number of timesthe LED flashes insequence, e.g., a singleflash for Level 1 (35$\u03bcs$ /27 mA) up to 11flashes for Level 11 (560$\u03bcs$ /54 mA).
Waveform	Asymmetrical, biphasic,rectangular waveformwith charge balancingsecond phase	Asymmetrical, biphasic,rectangular waveform withcharge balancing secondphase	Asymmetrical, biphasic,rectangular waveformwith charge balancingsecond phase
Maximum outputvoltage	14.0 V @ 500 Ω53.5 V @ 2000 Ω255 V @ 10,000 ΩAll voltages (±10%)	27.0 V @ 500 Ω108 V @ 2000 Ω255 V @ 10,000 ΩAll voltages (±10%)	27.0 V @ 500 Ω108 V @ 2000 Ω255 V @ 10,000 ΩAll voltages (±10%)
Maximum outputcurrent	27 mA @ 500 Ω27 mA @2000 Ω25.5 mA @ 10,000 ΩAll currents (±15%)	54 mA @ 500 Ω54 mA @ 2000 Ω25.5 mA @ 10,000 ΩAll currents (±15%)	54 mA @ 500 Ω54 mA @ 2000 Ω54 mA @ 10,000 ΩAll currents (±15%)
Pulse widths ( $\u03bcs$ )(@ currentsetting)	50, 70, 100, 140, 200,280, 400 (@ 27 mA)	50, 70, 100, 140, 200,280, 400, 560 (@ 54 mA)	35, 50, 70, 100, 140,200, 280 (@ 27 mA);280, 400 (@ 38 mA);400, 560 (@ 54 mA)
Frequency	1 Hz, fixed	1 Hz, fixed	1 Hz, fixed
Net charge	0 µC at 500Ω, capacitorcoupled	0 µC at 500Ω, capacitorcoupled	+/- 0.1 µC at 500Ω,phase balancing
Maximum phasecharge	18.3 µC at 500 Ω	40 µC at 500 Ω	40 µC at 500 Ω
Parameter	Predicategeko™ T-2	Predicategeko™ Plus R-2	Proposedgeko™ T-3
Maximum currentdensity	6.67 mA/cm²	13.3 mA/cm²	13.3 mA/cm²
Maximum powerdensity	0.000044 W/cm²	0.000088 W/cm²	0.000088 W/cm²
Timer range inminutes	1800 min max (30 hr runtime)	1800 min max (30 hr runtime)	1800 min max (30 hr runtime)
Power source	One 3V lithium coin cell	One 3V lithium coin cell	One 3V lithium coin cell
Weight	10 g	10 g	10 g
Dimensions	7.8" x 1.2" x 0.4"	7.8" x 1.2" x 0.4"	7.8" x 1.2" x 0.4"
Patient contactingmaterials	Hydrogel (KM10T)	Hydrogel (KM10T)	Hydrogel (KM10T)
Housing material	PolypropylenePlastic injection molding	PolypropylenePlastic injection molding	PolypropylenePlastic injection molding

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The differences between the proposed geko™ T-3 and the predicate geko models are:

More stimulus levels are available to the user: 11 in the geko™ T-3 as . compared to 7 in the geko™ T-2 and 8 in the geko™ Plus R-2.
The qeko T-3 offers three constant current levels: 27 mA, 38 mA, and 54 mA; . however, these are within the ranges available on the predicate models.
. The geko T-3 offers one additional short pulse width (35 µs) that is below the lowest pulse width available on the predicate models.
. The geko™ T-3 uses a different method of charge balancing; however, the net charge to the user remains essentially zero.

Otherwise, as can be seen from the Technical Comparison Table, the indications for use and technical specifications for the geko™ T-3 are the same as for the predicate models. None of the changes are associated with any new risks, nor do they change the risk levels previously identified in the geko risk analysis.

H. Design Validation Activities

The device changes described in this Special 510(k) were implemented under the company's design change procedures. A risk assessment of the changes resulted in the following verification and validation activities:

Electrical Safety and Electromagnetic Compatibility Testing - The geko™ T-3 has been certified to comply with the applicable clauses of the following standards:

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. IEC 60601-1:2005 +A1(2012) Medical electrical equipment - Part 1: General requirements for basic safety and essential performance
. IEC 60601-1-11:2015 Medical electrical equipment - Part 1-11: General requirements for basic safety and essential performance - Collateral Standard: Requirements for medical electrical equipment and medical electrical systems used in the home healthcare environment
. IEC 60601-2-10:2012 +A1(2016) Medical electrical equipment - Part 2-10: Particular requirements for the safety of nerve and muscle stimulators
. EN 60601-1-2:2015 Medical electrical equipment - Part 1-2: General requirements for basic safety and essential performance - Collateral standard: Electromagnetic disturbances - Requirements and tests

Hardware/Firmware Testing - The geko™ T-3 hardware and firmware were tested together in order to verify the correct functioning of the device. Testing included the following:

. Verification of output waveform characteristics via oscilloscope output tracings at 500Ω, 2kΩ and 10kΩ
Validation of all geko™ T-3 hardware and firmware functionality

Conclusion l.

The information and testing presented in this 510(k) demonstrated that the geko™ T-3 is substantially equivalent to the predicate geko devices, models T-2 and Plus R-2, for the intended uses of increasing local circulation, immediate post-surgical prevention of venous thrombosis, and edema reduction.

Regulation Number and Section

§ 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).