(267 days)
The geko™ T-1 Neuromuscular Stimulator is intended for:
- Increasing local blood circulation, and
- Immediate post-surgical stimulation of the calf muscles to prevent venous thrombosis.
The geko™ T-1 (geko™) Neuromuscular Stimulator is a disposable, fully integrated unit composed of a constant current pulse generator with embedded software and 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. A single button controls the On/Off function and the intensity level of the device, which is achieved through changes in the delivered pulse width. The geko™ 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.
Here's an analysis of the provided text regarding the acceptance criteria and study for the geko™ T-1 Neuromuscular Stimulator.
It's important to note that the provided document is a 510(k) summary for a medical device, which focuses on demonstrating substantial equivalence to a predicate device rather than outright proving effectiveness through a traditional clinical trial designed around specific acceptance criteria like those for a new drug. Therefore, some of the information requested might not be explicitly stated in the context of typical "acceptance criteria" but can be inferred from the equivalence arguments.
Acceptance Criteria and Reported Device Performance
The document does not explicitly present a table of "acceptance criteria" for performance metrics in the way one might see for a diagnostic AI. Instead, it demonstrates substantial equivalence to a predicate device (SYS*STIM ME 208) by comparing various technical and functional parameters, and by showing that the device achieves similar physiological effects (increased blood flow).
The substantial equivalence argument is built around the idea that the geko™ T-1 is as safe and effective as the predicate. The "acceptance criteria" in this context are implicitly that the geko™ T-1's performance is either similar to or better than the predicate device, especially in its indicated uses.
Table of "Acceptance Criteria" (Inferred from Substantial Equivalence Comparison) and Reported Device Performance:
| Parameter / Aspect of Performance | "Acceptance Criteria" (Inferred from Predicate Equivalence, or desired outcome) | Reported geko™ T-1 Performance |
|---|---|---|
| Intended Use | Subset of predicate's uses: Increasing local blood circulation, preventing venous thrombosis. | Meets this subset of indications. |
| Clinical Application | Prescription use in clinical/home setting, safe for single patient use. | Prescription use in clinical/home setting, single patient use for up to 30 hours (replacement recommended after 24 hours). |
| Electrical Safety | Compliance with IEC 60601-1, IEC 60601-2-10, IEC 60601-1-2. Patient leakage current within acceptable limits. | Complies with IEC 60601-1, IEC 60601-2-10, IEC 60601-1-2. Patient leakage current: < 20μA (Normal Condition), < 20μA (Single Fault Condition) - Better than predicate (<100μA, <300μA respectively). |
| Biocompatibility | Contact materials safe for prolonged skin contact (up to 30 days). | Hydrogel and adhesive strip tested per ISO 10993-1 for cytotoxicity, dermal sensitization, dermal irritation (including repeat irritation). All tests passed. |
| Software Verification & Validation | Software documentation consistent with moderate level of concern, all requirements met, hazards mitigated. | Software documentation provided, system validation demonstrated all software requirement specifications met and hazards mitigated to risk level 1 (Accept). |
| Device Output Waveforms | Net charge is zero. | Oscilloscope tracings at various loads (500Ω, 2kΩ, 10kΩ) and pulse widths (70-560 µs) demonstrated net charge is 0. |
| Shelf Life | Maintains performance for labeled shelf life. | Real-time shelf life testing at 30°C for 27 months showed device operational within specifications after 24 hours of operation, supporting a 24-month labeled shelf life. |
| Physiological Effect: Increased Venous Blood Velocity (Thromboprophylaxis) | Significant increase in venous blood velocity, comparable to or better than established alternatives. | Warwick et al. study: Peak venous velocity significantly higher (p<0.05) when geko™ was active in all postural positions, with and without plaster cast. Median discomfort rating was "minimal discomfort." Jawad et al. study: Significantly higher (p<0.001) venous and arterial blood volume flow and microcirculatory blood velocity compared to two commercial Intermittent Pneumatic Compression (IPC) devices. Ranges from "minimal sensation" to "mild discomfort." Unpublished THR study: Significantly increased venous blood velocity compared to no treatment; greater blood flow increase than Thromboembolism Deterrent Stockings (TEDS) group. |
| Patient Comfort / Adverse Events | Well-tolerated, minimal discomfort, no device-related adverse events. | Tucker et al.: 1 Hz frequency well tolerated by subjects. Warwick et al.: Median discomfort rating of 2 ("minimal discomfort"). Jawad et al.: Ranged from "minimal sensation" to "mild discomfort," no safety concerns reported. Unpublished THR study: No device-related adverse events reported. |
Study Details:
-
Sample size used for the test set and the data provenance:
- Tucker et al.: Not explicitly stated, described as "subjects." (This study was foundational, not directly for geko™ T-1 validation).
- Warwick et al.: 10 healthy volunteers.
- Jawad et al.: 10 healthy volunteers.
- Unpublished THR study: 40 patients undergoing elective unilateral total hip replacement.
Data Provenance:
- All studies appear to be prospective clinical investigations.
- The "Unpublished study conducted at the Harbour Hospital in Poole, Dorset, UK" indicates United Kingdom as the country of origin for that specific clinical data. The provenance of the Tucker, Warwick, and Jawad studies is not explicitly stated, but their citation format (Journal/authors) might lead back to UK-based research groups given the device manufacturer's location.
-
Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
This information is not applicable in the context of this device and studies. These are physiological measurements (blood flow velocity, volume, etc.) and patient perception, not interpretations requiring expert consensus for "ground truth" like in imaging diagnostics. The measurements themselves are the "ground truth" for the physiological effect.
-
Adjudication method (e.g. 2+1, 3+1, none) for the test set:
This information is not applicable. The studies involve objective physiological measurements (e.g., Doppler ultrasound) and subjective patient ratings (e.g., verbal rating scale, VAS), not an adjudication process of expert interpretations.
-
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:
This information is not applicable. This device is a neuromuscular stimulator, not an AI-powered diagnostic imaging tool. It does not involve "human readers" or "AI assistance" in the sense of image interpretation. The performance is the device's direct physiological effect.
-
If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
This information is not applicable. The geko™ T-1 is a powered muscle stimulator, a physical device, and not an algorithm or AI. Its performance is always "standalone" in the sense that it directly stimulates the muscle as intended, but it's used by a human (the patient or caregiver) who applies it and adjusts settings for comfort. The studies evaluate the device's effect without needing human interpretative input in the measurement process.
-
The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
The "ground truth" in these studies is primarily:
- Objective physiological measurements: Venous blood flow velocity, blood volume, microcirculatory flux/velocity (measured via Doppler ultrasound, ultrasound imaging).
- Subjective patient perception: Discomfort ratings (verbal rating scale, visual analog scale).
- Clinical outcomes (implied): For the THR study, the primary outcome measured was DVT prophylaxis efficacy parameters (blood flow increase), rather than direct DVT incidence, demonstrating the physiological mechanism to achieve the stated indication.
-
The sample size for the training set:
This information is not applicable. The geko™ T-1 is a physical medical device, not a machine learning model that requires a "training set." The design and engineering of the device are based on scientific principles and previous research (like the initial Tucker et al. study) but not a "training set" in the AI sense.
-
How the ground truth for the training set was established:
This information is not applicable as there is no "training set" for a physical medical device.
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Image /page/0/Picture/1 description: The image is a black and white logo for the U.S. Department of Health & Human Services. The logo features a stylized design of three human profiles facing right, with flowing lines suggesting movement or connection. The words "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" are arranged in a circular pattern around the design.
Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002
August 21, 2014
Firstkind Limited c/o Sheila Hemeon-Heyer, JD, RAC Radcliffe Consulting, Inc. 231 Fairbanks Street West Boylston, MA 01583
Re: K133638
Trade/Device Name: geko™ T-1 Neuromuscular Stimulator Regulation Number: 21 CFR 890.5850 Regulation Name: Powered Muscle Stimulator Regulatory Class: Class II Product Code: IPF Dated: July 25, 2014 Received: July 25, 2014
Dear Ms. 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 801); medical device reporting (reporting of medical device-related adverse events) (21 CFR 803); good manufacturing practice requirements as set
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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.
If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), please contact the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address
http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm. Also, please note the regulation entitled. "Misbranding by reference to premarket notification" (21CFR 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.
You may obtain other general information on your responsibilities under the Act from the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address
http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.
Sincerely yours,
Felipe Aquel -S
for Carlos L. Peña, Ph.D., M.S. 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) K133638
Device Name geko™ T-1 Neuromuscular Stimulator
Indications for Use (Describe)
The geko™ T-1 Neuromuscular Stimulator is intended for:
-
Increasing local blood circulation, and
-
Immediate post-surgical stimulation of the calf muscles to prevent venous thrombosis.
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)
PLEASE DO NOT WRITE BELOW THIS LINE - CONTINUE ON A SEPARATE PAGE IF NEEDED.
FOR FDA USE ONLY
Concurrence of Center for Devices and Radiological Health (CDRH) (Signature)
te: 2014.08.21 32 -04'00'
FORM FDA 3881 (9/13)
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510(k) Summary
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: Rachel Fallon Chief Technology Officer
+44 (0) 1494 572045 Tel: Email: rachel.fallon@firstkindmedical.com
B. Date Prepared: July 25, 2014
C. Device Name and Classification Information:
| Trade Name: | geko™ T-1 Neuromuscular Stimulator (geko) |
|---|---|
| Common/usual Name: | Powered Muscle Stimulator |
| Classification Name: | Stimulator, Muscle, Powered |
| Product Code, CFR: | IPF, 21 CFR 890.5850 |
| Panel code: | 89 |
| Class: | II |
- SYS*STIM ME 208 (K031017) D. Predicate Device:
Device Description: ய்
The qeko™ T-1 (qeko™) Neuromuscular Stimulator is a disposable, fully integrated unit composed of a constant current pulse generator with embedded software and 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. A single button controls the On/Off function and the intensity level of the device, which is achieved through changes in the delivered pulse width. The geko™ is applied so that the electrodes lie over the common peroneal nerve behind
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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 geko stimulus intensity varies with the pulse width, which can be set to one of seven levels to produce the appropriate muscle contraction within the patient comfort zone (70μs, 100μs, 140μs, 200μs, 400μs, and 560μs). 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 leg and foot muscles with a cadence and energy similar to that of walking.
Electrical contact is made with the patient through a hydrogel layer applied during manufacture to the integrated electrode. The patient contacting materials have been tested per the requirements of ISO 10993-1 and shown to be biocompatible for prolonged (up to 30 days) contact with intact skin. There are no separate electrode leads or electrodes.
F. Indications for Use:
The geko™ T-1 device is a Neuromuscular Stimulator and is intended for:
- Increasing local blood circulation, and .
- Immediate post-surgical stimulation of the calf muscles to prevent ● venous thrombosis.
G. Contraindications
Powered muscle stimulators should not be used on patients with cardiac demand pacemakers.
Powered muscle stimulators should not be used on patients with recently diagnosed deep vein thrombosis.
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| Parameter | geko™ T-1 | SYS*STIM ME 208(K031017) | SubstantialEquivalence |
|---|---|---|---|
| Intended Useand Indicationsfor Use | The geko T-1 is aneuromuscularstimulation device and isintended for:Increasing local bloodcirculation Immediate post-surgical stimulation ofthe calf muscles toprevent venousthrombosis | 1. Symptomatic relief ofchronic intractable pain,acute post traumatic painor acute post-surgical pain2. Temporary relation ofmuscle spasm3. Prevention of post-surgical phlebo-thrombosis throughimmediate stimulation ofcalf muscles4. Increasing local bloodcirculation5. Prevention orretardation of disuseatrophy6. Muscle re-education7. Maintaining orincreasing range of motion | The indications foruse of the geko™ T-1are a subset of theindications for use ofthe predicate device(see #3 and #4 forthe SYS*STIM 208) |
| Clinicalapplication | Prescription use only foruse in a clinical or homeuse setting.Single patient use for upto 30 hours (replacementrecommended after 24hours) | Prescription use only foruse in a clinical or homeuse setting.The device is reusable butthe electrodes are singleuse, disposable. | Substantiallyequivalent. Bothdevices are forprescription use in aclinical or homeenvironment. |
| AnatomicalSites | The electrodes areapplied to the posterioraspect of the knee onlyfor stimulation of theperoneal nerve. | Electrodes can be appliedto multiple anatomicalsites, including theposterior aspect of theknee only for stimulation ofthe peroneal nerve. | Substantiallyequivalent. Bothdevices can be usedfor stimulation of theperoneal nerve. |
| Parameter | geko™ T-1 | SYS*STIM ME 208(K031017) | SubstantialEquivalence |
| Basic Unit Characteristics | |||
| Power source | One CR2032 primarylithium coin cell. Notreplaceable by user | Mains (line) voltage | Substantiallyequivalent. Bothdevices meetelectrical safetystandards. |
| -Method of LineCurrentIsolation | N/A | Transformer isolation | |
| -PatientLeakageCurrent | Substantiallyequivalent. | ||
| -NormalCondition | < 20μA | <100 μA | Leakage current ofgeko is less than |
| -SingleFault Condition | < 20μA | <300 μA | predicate device. |
| Number ofoutput modes | Single mode with sevendiscrete stimulationsettings corresponding tothe seven pulse widths. | Three output modesThe "Pulse" mode has a200 μs pulse width | Substantiallyequivalent to "Pulse"mode of predicate. |
| Number ofoutputchannels | Single channel | Single channel | Same |
| -Synchronousor alternating | N/A (single channel) | N/A (single channel) | Same |
| -Method ofchannelisolation | Capacitor | Transformer | Substantiallyequivalent. Bothmethods are effectivemethods of channelisolation. |
| Regulatedcurrent orregulatedvoltage | Current regulated | Voltage regulated | Substantiallyequivalent. Bothmethods comply withelectrical safetystandards. |
| Microprocessorcontrolled? | Yes | Yes | Same |
| Parameter | geko™ T-1 | SYS*STIM ME 208(K031017) | SubstantialEquivalence |
| Automaticoverload trip | Yes | No | Substantiallyequivalent or better. |
| Automatic no-load trip | Yes | No | Substantiallyequivalent or better. |
| Automaticshut-off | Yes | Yes | Same |
| Patient over-ride control | Yes | Yes | Same |
| Indicatordisplay | |||
| - On/Off status | Yes | Yes | Same |
| - Low battery | Yes (device switches off) | N/A | Substantiallyequivalent |
| -Voltage /current level | N/A (device has fixedconstant current) | Yes (intensity control) | Substantiallyequivalent. |
| -Charge level(pulse width) | Yes (pulse width varies tochange deliveredcharge), The stimulationlevel (pulse width) isindicated by the flashingof the LED The numberof times LED flashes insequence indicates thelevel of stimulation, withlevel 1 (a single flash)equating to 70 μs beingthe lowest stimulationlevel and level 7 (7flashes in sequence)equating to 560 μs, thehighest. stimulation level | N/A (device has fixedpulse width (200 μs)). | Substantiallyequivalent. |
| Timer range inminutes | 1800 minutes maximum(device is disabled after30 hours battery run time) | 60 minute timer can bereset indefinitely | Substantiallyequivalent. |
| Parameter | geko™ T-1 | SYS*STIM ME 208(K031017) | SubstantialEquivalence |
| Compliancewith voluntarystandards | YesIEC 60601-1:1998 A1, A2IEC 60601-2-10:1987, A1EN 60601-1-2:2007ISO 10993-1 | YesUL 2601-1CAN/CSA-22.601.2.10-92 | Substantiallyequivalent |
| Compliancewith 21 CFR898 | N/A (electrodes areintegral with the device,there are no separateleads) | Yes | Substantiallyequivalent |
| Weight | 18 g | 1.4 pounds (636g) | Substantiallyequivalent. Bothdevices are smalland lightweight. |
| Dimensions | 6" x 1.6" x 0.43" | 2.75" x 6.1" x 8" | Substantiallyequivalent |
| Housingmaterial andconstruction | Plastic injection molding | Plastic injection molding | Substantiallyequivalent |
| Output Specifications | |||
| Waveform-Pulsedmonophasic orbiphasic- Shape | Biphasic (asymmetricalbiphasic with zero netDC)Rectangular, with chargebalancing second phase | Biphasic (asymmetricalbiphasic with zero net DC)Rectangular, with chargebalancing second phase | Same |
| Maximumoutput voltage | 13.5 V @ 500 Ω54 V @ 2000 Ω110 V @ 10,000 Ω | 92 V @ 500 Ω (measured)144 V @ 2000 Ω166 V @ 10,000 Ω | Substantiallyequivalent. Geko canoperate at lowervoltage as intensity isincreased byincreasing pulsewidth. |
| Maximumoutput current | 27 mA @ 500 Ω27 mA @2000 Ω11 mA @ 10,000 Ω | 184 mA @ 500 Ω72 mA @2000 Ω17 mA @ 10,000 Ω | Substantiallyequivalent for samereason as above. |
| Parameter | geko™ T-1 | SYS*STIM ME 208(K031017) | SubstantialEquivalence |
| Pulse width | 70, 100, 140, 200, 280,400, 560 µs | 200 µs | Substantiallyequivalent. Predicatevaries intensity byincreasingvoltage/current infixed pulse width. |
| Frequency | 1 Hz | 1 to 80 Hz | Substantiallyequivalent. Lowfrequency used toincrease circulation. |
| Forinterferentialmodes only:-beatFrequency (Hz) | N/A | N/A | Same |
| Multiphasicwaveforms | |||
| -Symmetricalphases | No | No | Same |
| -Phase duration | 70-560 µs for positivephase, second (negative)phase is an exponentialdecay with a 0.1 s timeconstant. | 200 µs | Substantiallyequivalent. Reasonspreviously discussed. |
| Net charge | 0 µC at 500 Ω | ~0 µC at 100 Ω | Same |
| -How achieved | Capacitor coupling | Transformer coupling | Methods aresubstantiallyequivalent. |
| Maximumphase charge | 18.3 µC at 500 Ω | 33.5 µC at 500 Ω | Substantiallyequivalent or better |
| Maximumcurrent density | 6.67 mA/cm² | 9.12 mA/cm² | Substantiallyequivalent or better. |
| Maximumpower density | 0.000044 W/cm² | 0.012 W/cm² | Substantiallyequivalent or better. |
| Parameter | geko™ T-1 | SYS*STIM ME 208(K031017) | SubstantialEquivalence |
| Burst modea) Pulses perburstb) Bursts persecondc) Burstduration(seconds)d) Duty Cycle[Line (b) xLine (c)] | N/A (single pulse, nopulse train or burst) | N/A when used in PULSEmode (single pulse) | Same. |
| ON Time(seconds) | N/A Stimulation isdelivered at 1 Hz, withsingle pulses of 70µs to560µs | N/A Stimulation isdelivered at 1 Hz, withsingle pulses of 200 µs | Same. |
| OFF Time(seconds) | N/A Stimulation isdelivered at 1 Hz, withsingle pulses of 70µs to560µs | N/A Stimulation isdelivered at 1 Hz, withsingle pulses of 200 µs | Same. |
| Additional Features | |||
| - On/Off status | Yes | Yes | Same |
| - Low battery | Yes (device switches off) | N/A (mains powered) | Substantiallyequivalent |
| -Voltage /current level | Yes. Fixed constantcurrent (pulse widthvaries to changedelivered charge) | Yes Continuously variableusing un-calibrated dial | Substantiallyequivalent |
| -Low stimcurrent | Yes. Unit turns off after 4minutes below lowcurrent threshold | No | Substantiallyequivalent or better |
| -High stimcurrent | Yes. Unit turns offimmediately | No | Substantiallyequivalent or better |
| Parameter | geko™ T-1 | SYS*STIM ME 208(K031017) | SubstantialEquivalence |
| Electrodes | Hydrogel applied to silverelectrode.Biocompatibility for thehydrogel has beenestablished. | Conductive adhesive gel | Substantiallyequivalent. Bothcomply with FDArecognizedstandards. |
| Cables/connectors | Integrated device: noseparate cables | Separate cables,assembled by user | Substantiallyequivalent or better. |
| Patient-contact | Contact is made throughintegrated self-adhesiveelectrodes. The geko™ T-1 is a single channeldevice. | Contact is made throughadhesive electrodes. TheSYS*STIM ME 208 is asingle channel device | Substantiallyequivalent |
H. Technical Comparison with the Predicate Device and Discussion of Differences
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-Nonclinical Data:
The following nonclinical testing was provided in this 510(k):
Shelf Life Testing - Real-time shelf life testing was conducted. Devices in their final packaging were stored under controlled conditions at 30°C for 27 months then subjected to full technical performance testing following 24 hours of operation. The results of this testing confirmed that the device remains fully operational in accordance with its performance specifications after 27 months of aging, and support a labelled shelf life of 24 months.
Biocompatibility Testing - The patient contacting materials of the device (hydrogel and adhesive strip) were subjected to biocompatibility testing per ISO 10993-1:2009, "Biological Evaluation of Medical Devices - Part 1: Evaluation and Testing," for devices in contact with intact skin, including cytotoxicity, dermal sensitization, and dermal irritation. In view of the potential for repeated sequential use of the device, repeat dermal irritation testing of the hydrogel was also conducted. All tests passed.
Software Verification and Validation - Software documentation consistent with a moderate level of concern was submitted in this 510(k). Latent software design flaws or faults would not be expected to result in user or patient injury. System validation testing presented in this 510(k)
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demonstrated that all software requirement specifications were met and all software hazards were mitigated to risk level 1 (Accept).
Electrical Safety and Electromagnetic Compatibility Testing - The geko™ T-1 has been certified by Intertek to comply with the applicable clauses of the following standards:
- IEC 60601-1: Medical Electrical Equipment Part 1: General ● Requirements for Safety, 1988; +A1:1991-11, +A2, 1995
- IEC 60601-2-10: Medical electrical equipment Part 2-10: Particular . requirements for the safety of nerve and muscle stimulators: 1987: +A1 2001
- IEC 60601-1-2: Medical electrical equipment Part 1-2: General . requirements for basic safety and essential performance - Collateral standard: Electromagnetic compatibility - Requirements and tests, 30 edition, 2007.
Engineering Bench Testing - In addition to the full system validation testing, the 510(k) also included testing in accordance with the recommendations of FDA's Guidance Document for Powered Muscle Stimulator 510(k)s, Attachment II, Section 1 - Output Waveforms. Oscilloscope tracings were obtained of the device output waveforms at each pulse width (i.e., intensity settings 1 through 7) under loads of 500Ω, 2 kΩ and 10kΩ. These tracings demonstrated that the net charge in the geko output waveform at all settings is 0.
J. Clinical Data
The safety and effectiveness of the geko™ T-1 has been evaluated in independent clinical studies. The work of Tucker et al." established that a 1 Hz frequency electrical stimulus applied at the common peroneal nerve resulted in significant increases (p<0.01) in venous volume flow, blood flow velocity, and microcirculatory flux in the stimulated leg as compared to the non-stimulated control leg. The changes in blood flow parameters were comparable amongst all stimulus frequencies (1 Hz to 5Hz); however, the highest amplitude/frequency programs reached a moderate discomfort level on the subject verbal rating scale, while the lowest frequency of 1 Hz was well
1 Tucker AT, Maass A, Bain DS, Chen L, Azzam M, Dawson H, Johnston A. Augmentation of venous, arterial and microvascular blood supply in the leg by isometric neuromuscular stimulation via the peroneal nerve. Int J Angiol 2010; Spring 19(1): e31-7.
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tolerated by all subjects. This work formed the basis for developing the geko™ T-1 device.
Subsequently, three independent investigations studied the safety and efficacy of the geko™ T-1: two in healthy subjects and one in patients undergoing elective unilateral total hip replacement. Warwick et al.2 applied the geko™ T-1 to the common peroneal nerve of 10 healthy volunteers, setting the simulation level to elicit a palpable twitch of the foot, according to the manufacturer's instructions. Assessments of blood flow velocity, volume and average velocity using Doppler ultrasound, and vessel diameter using ultrasound imaging were made with the subjects in four positions: 1) lying supine, lower limb horizontal; 2) supine, lower limb elevated at 25 to 35 degrees hip flexion; 3) standing, non weight-bearing (weight on contralateral leg only); and 4) standing, weight-bearing (weight evenly distributed on both legs). Assessments were made after 10 minutes in each position with the geko™ T-1 turned off, then repeated in each position during active stimulation. A plaster cast was then applied to the lower limb of each subject, and the assessments were repeated, first with the geko™ T-1 inactive and then with the device active.
In all postural positions, both with and without the plaster cast, peak venous velocity was significantly higher (p<0.05) when the geko™ was active. There were no significant effects on blood flow due to the presence of the plaster cast or change in postural position for the active geko™ measurements. The median discomfort rating for all positions while the geko™ was active was 2, corresponding to "minimal discomfort."
Jawad et al.3 compared the effectiveness of neuromuscular electrostimulation using the geko™ to two commercially available intermittent pneumatic compression (IPC) devices in 10 healthy volunteers. Measurements of lower leg blood flow, blood volume, and microcirculatory velocity were taken after 30 minutes of supine rest and then following 30 minutes of active application of each device type applied bilaterally in a predefined randomized pattern. The geko™ T-1 was applied at both the
2 Warwick D, Shaikh A, Gadola S, Stokes M, Worsley P, Bain D, Tucker A, Gadola SD: Neuromuscular electrostimulation via the common peroneal nerve promotes lower limb flow in a below-knee cast: a potential thromboprophylaxis. Bone Joint Res, Sep 2013, 2(9):179-85. 3 Jawad H, Bain DS, Dawson H, Crawford K. A comparative study investigating the effectiveness of neuromuscular electrostimulation versus intermittent pneumatic compression in enhancing
lower limb blood flow in healthy subjects. Submitted for publication to J Thrombosis and Haemostasis.
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subject's threshold level for muscle twitch and a setting three levels above the threshold.
The authors reported that neuromuscular stimulation using the geko™ T-1 resulted in significantly higher (p<0.001) venous and arterial blood volume flow measures and microcirculatory blood velocity at both settings as compared to both of the IPC devices. There were no safety concerns reported for any of the devices used. Subject perception ratings evaluated using a visual analog scale (VAS) and a verbal rating scale (VRS) ranged from "minimal sensation" to "mild discomfort." The authors concluded that the geko™ T-1 was superior to the IPC devices in enhancing blood flow in the lower limbs, even when used at the subject's threshold setting.
The geko™ T-1 device was also studied in a group of 40 patients undergoing elective unilateral total hip replacement (THR) who were randomized to receive post-surgical DVT prophylaxis treatment with either the geko™ T-1 or Thromboembolism Deterrent Stockings (TEDS).4 The intervention was worn from immediately post-surgery to hospital discharge, which was 4 days for most subjects (the geko™ T-1 was changed every 24 hours). The study results demonstrated that: 1) use of the geko™ T-1 significantly increased venous blood velocity as compared to no treatment; and 2) the blood flow increase seen in the geko™ group was greater than in the TEDS group. There were no device-related adverse events reported in this study. Given that the performance of prophylactic interventions for DVT is conventionally measured in terms of venous flow augmentation, this study demonstrated that the geko T-1 is both safe and effective for use in post-surgical prevention of DVT.
I. Conclusions
The information and testing presented in this 510(k) demonstrated that that the geko™ T-1 performs as designed and intended and is substantially equivalent to the predicate device, the SYS*STIM ME 208, for the indications of neuromuscular stimulation of the peroneal nerve to increase local circulation and for immediate post-surgical prevention of DVT.
4 Unpublished study conducted at the Harbour Hospital in Poole, Dorset, UK.
§ 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).